bevy/crates/bevy_reflect/src/lib.rs

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// FIXME(3492): remove once docs are ready
#![allow(missing_docs)]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![doc(
html_logo_url = "https://bevyengine.org/assets/icon.png",
html_favicon_url = "https://bevyengine.org/assets/icon.png"
)]
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! Reflection in Rust.
//!
//! [Reflection] is a powerful tool provided within many programming languages
//! that allows for meta-programming: using information _about_ the program to
//! _affect_ the program.
//! In other words, reflection allows us to inspect the program itself, its
//! syntax, and its type information at runtime.
//!
//! This crate adds this missing reflection functionality to Rust.
//! Though it was made with the [Bevy] game engine in mind,
//! it's a general-purpose solution that can be used in any Rust project.
//!
//! At a very high level, this crate allows you to:
//! * Dynamically interact with Rust values
//! * Access type metadata at runtime
//! * Serialize and deserialize (i.e. save and load) data
//!
//! It's important to note that because of missing features in Rust,
//! there are some [limitations] with this crate.
//!
//! # The `Reflect` Trait
//!
//! At the core of [`bevy_reflect`] is the [`Reflect`] trait.
//!
//! One of its primary purposes is to allow all implementors to be passed around
//! as a `dyn Reflect` trait object.
//! This allows any such type to be operated upon completely dynamically (at a small [runtime cost]).
//!
//! Implementing the trait is easily done using the provided [derive macro]:
//!
//! ```
//! # use bevy_reflect::Reflect;
//! #[derive(Reflect)]
//! struct MyStruct {
//! foo: i32
//! }
//! ```
//!
//! This will automatically generate the implementation of `Reflect` for any struct or enum.
//!
//! It will also generate other very important trait implementations used for reflection:
//! * [`GetTypeRegistration`]
//! * [`Typed`]
//! * [`Struct`], [`TupleStruct`], or [`Enum`] depending on the type
//!
//! ## Requirements
//!
//! We can implement `Reflect` on any type that satisfies _both_ of the following conditions:
//! * The type implements `Any`.
//! This is true if and only if the type itself has a [`'static` lifetime].
//! * All fields and sub-elements themselves implement `Reflect`
//! (see the [derive macro documentation] for details on how to ignore certain fields when deriving).
//!
//! Additionally, using the derive macro on enums requires a third condition to be met:
//! * All fields and sub-elements must implement [`FromReflect`]—
//! another important reflection trait discussed in a later section.
//!
//! # The `Reflect` Subtraits
//!
//! Since [`Reflect`] is meant to cover any and every type, this crate also comes with a few
//! more traits to accompany `Reflect` and provide more specific interactions.
//! We refer to these traits as the _reflection subtraits_ since they all have `Reflect` as a supertrait.
//! The current list of reflection subtraits include:
//! * [`Tuple`]
//! * [`Array`]
//! * [`List`]
//! * [`Map`]
//! * [`Struct`]
//! * [`TupleStruct`]
//! * [`Enum`]
//!
//! As mentioned previously, the last three are automatically implemented by the [derive macro].
//!
//! Each of these traits come with their own methods specific to their respective category.
//! For example, we can access our struct's fields by name using the [`Struct::field`] method.
//!
//! ```
//! # use bevy_reflect::{Reflect, Struct};
//! # #[derive(Reflect)]
//! # struct MyStruct {
//! # foo: i32
//! # }
//! let my_struct: Box<dyn Struct> = Box::new(MyStruct {
//! foo: 123
//! });
//! let foo: &dyn Reflect = my_struct.field("foo").unwrap();
//! assert_eq!(Some(&123), foo.downcast_ref::<i32>());
//! ```
//!
//! Since most data is passed around as `dyn Reflect`,
//! the `Reflect` trait has methods for going to and from these subtraits.
//!
//! [`Reflect::reflect_kind`], [`Reflect::reflect_ref`], [`Reflect::reflect_mut`], and [`Reflect::reflect_owned`] all return
//! an enum that respectively contains zero-sized, immutable, mutable, and owned access to the type as a subtrait object.
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//!
//! For example, we can get out a `dyn Tuple` from our reflected tuple type using one of these methods.
//!
//! ```
//! # use bevy_reflect::{Reflect, ReflectRef};
//! let my_tuple: Box<dyn Reflect> = Box::new((1, 2, 3));
//! let ReflectRef::Tuple(my_tuple) = my_tuple.reflect_ref() else { unreachable!() };
//! assert_eq!(3, my_tuple.field_len());
//! ```
//!
//! And to go back to a general-purpose `dyn Reflect`,
//! we can just use the matching [`Reflect::as_reflect`], [`Reflect::as_reflect_mut`],
//! or [`Reflect::into_reflect`] methods.
//!
//! ## Value Types
//!
//! Types that do not fall under one of the above subtraits,
//! such as for primitives (e.g. `bool`, `usize`, etc.)
//! and simple types (e.g. `String`, `Duration`),
//! are referred to as _value_ types
//! since methods like [`Reflect::reflect_ref`] return a [`ReflectRef::Value`] variant.
//! While most other types contain their own `dyn Reflect` fields and data,
//! these types generally cannot be broken down any further.
//!
//! # Dynamic Types
//!
//! Each subtrait comes with a corresponding _dynamic_ type.
//!
//! The available dynamic types are:
//! * [`DynamicTuple`]
//! * [`DynamicArray`]
//! * [`DynamicList`]
//! * [`DynamicMap`]
//! * [`DynamicStruct`]
//! * [`DynamicTupleStruct`]
//! * [`DynamicEnum`]
//!
//! These dynamic types may contain any arbitrary reflected data.
//!
//! ```
//! # use bevy_reflect::{DynamicStruct, Struct};
//! let mut data = DynamicStruct::default();
//! data.insert("foo", 123_i32);
//! assert_eq!(Some(&123), data.field("foo").unwrap().downcast_ref::<i32>())
//! ```
//!
//! They are most commonly used as "proxies" for other types,
//! where they contain the same data as— and therefore, represent— a concrete type.
//! The [`Reflect::clone_value`] method will return a dynamic type for all non-value types,
//! allowing all types to essentially be "cloned".
//! And since dynamic types themselves implement [`Reflect`],
//! we may pass them around just like any other reflected type.
//!
//! ```
//! # use bevy_reflect::{DynamicStruct, Reflect};
//! # #[derive(Reflect)]
//! # struct MyStruct {
//! # foo: i32
//! # }
//! let original: Box<dyn Reflect> = Box::new(MyStruct {
//! foo: 123
//! });
//!
//! // `cloned` will be a `DynamicStruct` representing a `MyStruct`
//! let cloned: Box<dyn Reflect> = original.clone_value();
//! assert!(cloned.represents::<MyStruct>());
//! assert!(cloned.is::<DynamicStruct>());
//! ```
//!
//! ## Patching
//!
//! These dynamic types come in handy when needing to apply multiple changes to another type.
//! This is known as "patching" and is done using the [`Reflect::apply`] method.
//!
//! ```
//! # use bevy_reflect::{DynamicEnum, Reflect};
//! let mut value = Some(123_i32);
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
//! let patch = DynamicEnum::new("None", ());
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! value.apply(&patch);
//! assert_eq!(None, value);
//! ```
//!
//! ## `FromReflect`
//!
//! It's important to remember that dynamic types are _not_ the concrete type they may be representing.
//! A common mistake is to treat them like such when trying to cast back to the original type
//! or when trying to make use of a reflected trait which expects the actual type.
//!
//! ```should_panic
//! # use bevy_reflect::{DynamicStruct, Reflect};
//! # #[derive(Reflect)]
//! # struct MyStruct {
//! # foo: i32
//! # }
//! let original: Box<dyn Reflect> = Box::new(MyStruct {
//! foo: 123
//! });
//!
//! let cloned: Box<dyn Reflect> = original.clone_value();
//! let value = cloned.take::<MyStruct>().unwrap(); // PANIC!
//! ```
//!
//! To resolve this issue, we'll need to convert the dynamic type to the concrete one.
//! This is where [`FromReflect`] comes in.
//!
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! `FromReflect` is a trait that allows an instance of a type to be generated from a
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! dynamic representation— even partial ones.
//! And since the [`FromReflect::from_reflect`] method takes the data by reference,
//! this can be used to effectively clone data (to an extent).
//!
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! It is automatically implemented when [deriving `Reflect`] on a type unless opted out of
//! using `#[reflect(from_reflect = false)]` on the item.
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//!
//! ```
//! # use bevy_reflect::{Reflect, FromReflect};
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! #[derive(Reflect)]
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! struct MyStruct {
//! foo: i32
//! }
//! let original: Box<dyn Reflect> = Box::new(MyStruct {
//! foo: 123
//! });
//!
//! let cloned: Box<dyn Reflect> = original.clone_value();
//! let value = <MyStruct as FromReflect>::from_reflect(&*cloned).unwrap(); // OK!
//! ```
//!
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! When deriving, all active fields and sub-elements must also implement `FromReflect`.
//!
//! Fields can be given default values for when a field is missing in the passed value or even ignored.
//! Ignored fields must either implement [`Default`] or have a default function specified
//! using `#[reflect(default = "path::to::function")]`.
//!
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! See the [derive macro documentation](derive@crate::FromReflect) for details.
//!
//! All primitives and simple types implement `FromReflect` by relying on their [`Default`] implementation.
//!
Refactor `path` module of `bevy_reflect` (#8887) # Objective - The `path` module was getting fairly large. - The code in `AccessRef::read_element` and mut equivalent was very complex and difficult to understand. - The `ReflectPathError` had a lot of variants, and was difficult to read. ## Solution - Split the file in two, `access` now has its own module - Rewrite the `read_element` methods, they were ~200 lines long, they are now ~70 lines long — I didn't change any of the logic. It's really just the same code, but error handling is separated. - Split the `ReflectPathError` error - Merge `AccessRef` and `Access` - A few other changes that aim to reduce code complexity ### Fully detailed change list - `Display` impl of `ParsedPath` now includes prefix dots — this allows simplifying its implementation, and IMO `.path.to.field` is a better way to express a "path" than `path.to.field` which could suggest we are reading the `to` field of a variable named `path` - Add a test to check that dot prefixes and other are correctly parsed — Until now, no test contained a prefixing dot - Merge `Access` and `AccessRef`, using a `Cow<'a, str>`. Generated code seems to agree with this decision (`ParsedPath::parse` sheds 5% of instructions) - Remove `Access::as_ref` since there is no such thing as an `AccessRef` anymore. - Rename `AccessRef::to_owned` into `AccessRef::into_owned()` since it takes ownership of `self` now. - Add a `parse_static` that doesn't allocate new strings for named fields! - Add a section about path reflection in the `bevy_reflect` crate root doc — I saw a few people that weren't aware of path reflection, so I thought it was pertinent to add it to the root doc - a lot of nits - rename `index` to `offset` when it refers to offset in the path string — There is no more confusion with the other kind of indices in this context, also it's a common naming convention for parsing. - Make a dedicated enum for parsing errors - rename the `read_element` methods to `element` — shorter, but also `read_element_mut` was a fairly poor name - The error values now not only contain the expected type but also the actual type. - Remove lifetimes that could be inferred from the `GetPath` trait methods. --- ## Change log - Added the `ParsedPath::parse_static` method, avoids allocating when parsing `&'static str`. ## Migration Guide If you were matching on the `Err(ReflectPathError)` value returned by `GetPath` and `ParsedPath` methods, now only the parse-related errors and the offset are publicly accessible. You can always use the `fmt::Display` to get a clear error message, but if you need programmatic access to the error types, please open an issue. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-07-30 19:17:07 +00:00
//! # Path navigation
//!
//! The [`GetPath`] trait allows accessing arbitrary nested fields of a [`Reflect`] type.
//!
//! Using `GetPath`, it is possible to use a path string to access a specific field
//! of a reflected type.
//!
//! ```
//! # use bevy_reflect::{Reflect, GetPath};
//! #[derive(Reflect)]
//! struct MyStruct {
//! value: Vec<Option<u32>>
//! }
//!
//! let my_struct = MyStruct {
//! value: vec![None, None, Some(123)],
//! };
//! assert_eq!(
//! my_struct.path::<u32>(".value[2].0").unwrap(),
//! &123,
//! );
//! ```
//!
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! # Type Registration
//!
//! This crate also comes with a [`TypeRegistry`] that can be used to store and retrieve additional type metadata at runtime,
//! such as helper types and trait implementations.
//!
//! The [derive macro] for [`Reflect`] also generates an implementation of the [`GetTypeRegistration`] trait,
//! which is used by the registry to generate a [`TypeRegistration`] struct for that type.
//! We can then register additional [type data] we want associated with that type.
//!
//! For example, we can register [`ReflectDefault`] on our type so that its `Default` implementation
//! may be used dynamically.
//!
//! ```
//! # use bevy_reflect::{Reflect, TypeRegistry, prelude::ReflectDefault};
//! #[derive(Reflect, Default)]
//! struct MyStruct {
//! foo: i32
//! }
//! let mut registry = TypeRegistry::empty();
//! registry.register::<MyStruct>();
//! registry.register_type_data::<MyStruct, ReflectDefault>();
//!
//! let registration = registry.get(std::any::TypeId::of::<MyStruct>()).unwrap();
//! let reflect_default = registration.data::<ReflectDefault>().unwrap();
//!
//! let new_value: Box<dyn Reflect> = reflect_default.default();
//! assert!(new_value.is::<MyStruct>());
//! ```
//!
//! Because this operation is so common, the derive macro actually has a shorthand for it.
//! By using the `#[reflect(Trait)]` attribute, the derive macro will automatically register a matching,
//! in-scope `ReflectTrait` type within the `GetTypeRegistration` implementation.
//!
//! ```
//! use bevy_reflect::prelude::{Reflect, ReflectDefault};
//!
//! #[derive(Reflect, Default)]
//! #[reflect(Default)]
//! struct MyStruct {
//! foo: i32
//! }
//! ```
//!
//! ## Reflecting Traits
//!
//! Type data doesn't have to be tied to a trait, but it's often extremely useful to create trait type data.
//! These allow traits to be used directly on a `dyn Reflect` while utilizing the underlying type's implementation.
//!
//! For any [object-safe] trait, we can easily generate a corresponding `ReflectTrait` type for our trait
//! using the [`#[reflect_trait]`](reflect_trait) macro.
//!
//! ```
//! # use bevy_reflect::{Reflect, reflect_trait, TypeRegistry};
//! #[reflect_trait] // Generates a `ReflectMyTrait` type
//! pub trait MyTrait {}
//! impl<T: Reflect> MyTrait for T {}
//!
//! let mut registry = TypeRegistry::new();
//! registry.register_type_data::<i32, ReflectMyTrait>();
//! ```
//!
//! The generated type data can be used to convert a valid `dyn Reflect` into a `dyn MyTrait`.
//! See the [trait reflection example](https://github.com/bevyengine/bevy/blob/latest/examples/reflection/trait_reflection.rs)
//! for more information and usage details.
//!
//! # Serialization
//!
//! By using reflection, we are also able to get serialization capabilities for free.
//! In fact, using [`bevy_reflect`] can result in faster compile times and reduced code generation over
//! directly deriving the [`serde`] traits.
//!
//! The way it works is by moving the serialization logic into common serializers and deserializers:
//! * [`ReflectSerializer`]
//! * [`TypedReflectSerializer`]
//! * [`UntypedReflectDeserializer`]
//! * [`TypedReflectDeserializer`]
//!
//! All of these structs require a reference to the [registry] so that [type information] can be retrieved,
//! as well as registered type data, such as [`ReflectSerialize`] and [`ReflectDeserialize`].
//!
//! The general entry point are the "untyped" versions of these structs.
//! These will automatically extract the type information and pass them into their respective "typed" version.
//!
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
//! The output of the `ReflectSerializer` will be a map, where the key is the [type path]
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! and the value is the serialized data.
//! The `TypedReflectSerializer` will simply output the serialized data.
//!
//! The `UntypedReflectDeserializer` can be used to deserialize this map and return a `Box<dyn Reflect>`,
//! where the underlying type will be a dynamic type representing some concrete type (except for value types).
//!
//! Again, it's important to remember that dynamic types may need to be converted to their concrete counterparts
//! in order to be used in certain cases.
//! This can be achieved using [`FromReflect`].
//!
//! ```
//! # use serde::de::DeserializeSeed;
//! # use bevy_reflect::{
//! # serde::{ReflectSerializer, UntypedReflectDeserializer},
//! # Reflect, FromReflect, TypeRegistry
//! # };
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! #[derive(Reflect, PartialEq, Debug)]
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! struct MyStruct {
//! foo: i32
//! }
//!
//! let original_value = MyStruct {
//! foo: 123
//! };
//!
//! // Register
//! let mut registry = TypeRegistry::new();
//! registry.register::<MyStruct>();
//!
//! // Serialize
//! let reflect_serializer = ReflectSerializer::new(&original_value, &registry);
//! let serialized_value: String = ron::to_string(&reflect_serializer).unwrap();
//!
//! // Deserialize
//! let reflect_deserializer = UntypedReflectDeserializer::new(&registry);
//! let deserialized_value: Box<dyn Reflect> = reflect_deserializer.deserialize(
//! &mut ron::Deserializer::from_str(&serialized_value).unwrap()
//! ).unwrap();
//!
//! // Convert
//! let converted_value = <MyStruct as FromReflect>::from_reflect(&*deserialized_value).unwrap();
//!
//! assert_eq!(original_value, converted_value);
//! ```
//!
//! # Limitations
//!
//! While this crate offers a lot in terms of adding reflection to Rust,
//! it does come with some limitations that don't make it as featureful as reflection
//! in other programming languages.
//!
//! ## Non-Static Lifetimes
//!
//! One of the most obvious limitations is the `'static` requirement.
//! Rust requires fields to define a lifetime for referenced data,
//! but [`Reflect`] requires all types to have a `'static` lifetime.
//! This makes it impossible to reflect any type with non-static borrowed data.
//!
//! ## Function Reflection
//!
//! Another limitation is the inability to fully reflect functions and methods.
//! Most languages offer some way of calling methods dynamically,
//! but Rust makes this very difficult to do.
//! For non-generic methods, this can be done by registering custom [type data] that
//! contains function pointers.
//! For generic methods, the same can be done but will typically require manual monomorphization
//! (i.e. manually specifying the types the generic method can take).
//!
//! ## Manual Registration
//!
//! Since Rust doesn't provide built-in support for running initialization code before `main`,
//! there is no way for `bevy_reflect` to automatically register types into the [type registry].
//! This means types must manually be registered, including their desired monomorphized
//! representations if generic.
//!
//! # Features
//!
//! ## `bevy`
//!
//! | Default | Dependencies |
//! | :-----: | :---------------------------------------: |
//! | ❌ | [`bevy_math`], [`glam`], [`smallvec`] |
//!
//! This feature makes it so that the appropriate reflection traits are implemented on all the types
//! necessary for the [Bevy] game engine.
//! enables the optional dependencies: [`bevy_math`], [`glam`], and [`smallvec`].
//! These dependencies are used by the [Bevy] game engine and must define their reflection implementations
//! within this crate due to Rust's [orphan rule].
//!
//! ## `documentation`
//!
//! | Default | Dependencies |
//! | :-----: | :-------------------------------------------: |
//! | ❌ | [`bevy_reflect_derive/documentation`] |
//!
//! This feature enables capturing doc comments as strings for items that [derive `Reflect`].
//! Documentation information can then be accessed at runtime on the [`TypeInfo`] of that item.
//!
//! This can be useful for generating documentation for scripting language interop or
//! for displaying tooltips in an editor.
//!
//! [Reflection]: https://en.wikipedia.org/wiki/Reflective_programming
//! [Bevy]: https://bevyengine.org/
//! [limitations]: #limitations
//! [`bevy_reflect`]: crate
//! [runtime cost]: https://doc.rust-lang.org/book/ch17-02-trait-objects.html#trait-objects-perform-dynamic-dispatch
//! [derive macro]: derive@crate::Reflect
//! [`'static` lifetime]: https://doc.rust-lang.org/rust-by-example/scope/lifetime/static_lifetime.html#trait-bound
//! [derive macro documentation]: derive@crate::Reflect
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
//! [deriving `Reflect`]: derive@crate::Reflect
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! [type data]: TypeData
//! [`ReflectDefault`]: std_traits::ReflectDefault
//! [object-safe]: https://doc.rust-lang.org/reference/items/traits.html#object-safety
//! [`serde`]: ::serde
//! [`ReflectSerializer`]: serde::ReflectSerializer
//! [`TypedReflectSerializer`]: serde::TypedReflectSerializer
//! [`UntypedReflectDeserializer`]: serde::UntypedReflectDeserializer
//! [`TypedReflectDeserializer`]: serde::TypedReflectDeserializer
//! [registry]: TypeRegistry
//! [type information]: TypeInfo
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
//! [type path]: TypePath
bevy_reflect: Improved documentation (#7148) # Objective `bevy_reflect` can be a moderately complex crate to try and understand. It has many moving parts, a handful of gotchas, and a few subtle contracts that aren't immediately obvious to users and even other contributors. The current README does an okay job demonstrating how the crate can be used. However, the crate's actual documentation should give a better overview of the crate, its inner-workings, and show some of its own examples. ## Solution Added crate-level documentation that attempts to summarize the main parts of `bevy_reflect` into small sections. This PR also updates the documentation for: - `Reflect` - `FromReflect` - The reflection subtraits - Other important types and traits - The reflection macros (including the derive macros) - Crate features ### Open Questions 1. ~~Should I update the docs for the Dynamic types? I was originally going to, but I'm getting a little concerned about the size of this PR 😅~~ Decided to not do this in this PR. It'll be better served from its own PR. 2. Should derive macro documentation be moved to the trait itself? This could improve visibility and allow for better doc links, but could also clutter up the trait's documentation (as well as not being on the actual derive macro's documentation). ### TODO - [ ] ~~Document Dynamic types (?)~~ I think this should be done in a separate PR. - [x] Document crate features - [x] Update docs for `GetTypeRegistration` - [x] Update docs for `TypeRegistration` - [x] Update docs for `derive_from_reflect` - [x] Document `reflect_trait` - [x] Document `impl_reflect_value` - [x] Document `impl_from_reflect_value` --- ## Changelog - Updated documentation across the `bevy_reflect` crate - Removed `#[module]` helper attribute for `Reflect` derives (this is not currently used) ## Migration Guide - Removed `#[module]` helper attribute for `Reflect` derives. If your code is relying on this attribute, please replace it with either `#[reflect]` or `#[reflect_value]` (dependent on use-case). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2023-02-18 20:42:01 +00:00
//! [type registry]: TypeRegistry
//! [`bevy_math`]: https://docs.rs/bevy_math/latest/bevy_math/
//! [`glam`]: https://docs.rs/glam/latest/glam/
//! [`smallvec`]: https://docs.rs/smallvec/latest/smallvec/
//! [orphan rule]: https://doc.rust-lang.org/book/ch10-02-traits.html#implementing-a-trait-on-a-type:~:text=But%20we%20can%E2%80%99t,implementation%20to%20use.
//! [`bevy_reflect_derive/documentation`]: bevy_reflect_derive
//! [derive `Reflect`]: derive@crate::Reflect
mod array;
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
mod fields;
bevy_reflect: Add `ReflectFromReflect` (v2) (#6245) # Objective Resolves #4597 (based on the work from #6056 and a refresh of #4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed #4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open #4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-12-11 17:52:48 +00:00
mod from_reflect;
2020-11-28 00:39:59 +00:00
mod list;
mod map;
mod path;
mod reflect;
mod struct_trait;
mod tuple;
2020-11-28 00:39:59 +00:00
mod tuple_struct;
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
mod type_info;
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
mod type_path;
2020-11-28 00:39:59 +00:00
mod type_registry;
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
2020-11-28 00:39:59 +00:00
mod impls {
#[cfg(feature = "glam")]
mod glam;
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
Move `sprite::Rect` into `bevy_math` (#5686) # Objective Promote the `Rect` utility of `sprite::Rect`, which defines a rectangle by its minimum and maximum corners, to the `bevy_math` crate to make it available as a general math type to all crates without the need to depend on the `bevy_sprite` crate. Fixes #5575 ## Solution Move `sprite::Rect` into `bevy_math` and fix all uses. Implement `Reflect` for `Rect` directly into the `bevy_reflect` crate by having `bevy_reflect` depend on `bevy_math`. This looks like a new dependency, but the `bevy_reflect` was "cheating" for other math types by directly depending on `glam` to reflect other math types, thereby giving the illusion that there was no dependency on `bevy_math`. In practice conceptually Bevy's math types are reflected into the `bevy_reflect` crate to avoid a dependency of that crate to a "lower level" utility crate like `bevy_math` (which in turn would make `bevy_reflect` be a dependency of most other crates, and increase the risk of circular dependencies). So this change simply formalizes that dependency in `Cargo.toml`. The `Rect` struct is also augmented in this change with a collection of utility methods to improve its usability. A few uses cases are updated to use those new methods, resulting is more clear and concise syntax. --- ## Changelog ### Changed - Moved the `sprite::Rect` type into `bevy_math`. ### Added - Added several utility methods to the `math::Rect` type. ## Migration Guide The `bevy::sprite::Rect` type moved to the math utility crate as `bevy::math::Rect`. You should change your imports from `use bevy::sprite::Rect` to `use bevy::math::Rect`.
2022-09-02 12:35:23 +00:00
#[cfg(feature = "bevy_math")]
mod math {
mod direction;
mod primitives2d;
mod primitives3d;
mod rect;
Add `Rotation2d` (#11658) # Objective Rotating vectors is a very common task. It is required for a variety of things both within Bevy itself and in many third party plugins, for example all over physics and collision detection, and for things like Bevy's bounding volumes and several gizmo implementations. For 3D, we can do this using a `Quat`, but for 2D, we do not have a clear and efficient option. `Mat2` can be used for rotating vectors if created using `Mat2::from_angle`, but this is not obvious to many users, it doesn't have many rotation helpers, and the type does not give any guarantees that it represents a valid rotation. We should have a proper type for 2D rotations. In addition to allowing for potential optimization, it would allow us to have a consistent and explicitly documented representation used throughout the engine, i.e. counterclockwise and in radians. ## Representation The mathematical formula for rotating a 2D vector is the following: ``` new_x = x * cos - y * sin new_y = x * sin + y * cos ``` Here, `sin` and `cos` are the sine and cosine of the rotation angle. Computing these every time when a vector needs to be rotated can be expensive, so the rotation shouldn't be just an `f32` angle. Instead, it is often more efficient to represent the rotation using the sine and cosine of the angle instead of storing the angle itself. This can be freely passed around and reused without unnecessary computations. The two options are either a 2x2 rotation matrix or a unit complex number where the cosine is the real part and the sine is the imaginary part. These are equivalent for the most part, but the unit complex representation is a bit more memory efficient (two `f32`s instead of four), so I chose that. This is like Nalgebra's [`UnitComplex`](https://docs.rs/nalgebra/latest/nalgebra/geometry/type.UnitComplex.html) type, which can be used for the [`Rotation2`](https://docs.rs/nalgebra/latest/nalgebra/geometry/type.Rotation2.html) type. ## Implementation Add a `Rotation2d` type represented as a unit complex number: ```rust /// A counterclockwise 2D rotation in radians. /// /// The rotation angle is wrapped to be within the `]-pi, pi]` range. pub struct Rotation2d { /// The cosine of the rotation angle in radians. /// /// This is the real part of the unit complex number representing the rotation. pub cos: f32, /// The sine of the rotation angle in radians. /// /// This is the imaginary part of the unit complex number representing the rotation. pub sin: f32, } ``` Using it is similar to using `Quat`, but in 2D: ```rust let rotation = Rotation2d::radians(PI / 2.0); // Rotate vector (also works on Direction2d!) assert_eq!(rotation * Vec2::X, Vec2::Y); // Get angle as degrees assert_eq!(rotation.as_degrees(), 90.0); // Getting sin and cos is free let (sin, cos) = rotation.sin_cos(); // "Subtract" rotations let rotation2 = Rotation2d::FRAC_PI_4; // there are constants! let diff = rotation * rotation2.inverse(); assert_eq!(diff.as_radians(), PI / 4.0); // This is equivalent to the above assert_eq!(rotation2.angle_between(rotation), PI / 4.0); // Lerp let rotation1 = Rotation2d::IDENTITY; let rotation2 = Rotation2d::FRAC_PI_2; let result = rotation1.lerp(rotation2, 0.5); assert_eq!(result.as_radians(), std::f32::consts::FRAC_PI_4); // Slerp let rotation1 = Rotation2d::FRAC_PI_4); let rotation2 = Rotation2d::degrees(-180.0); // we can use degrees too! let result = rotation1.slerp(rotation2, 1.0 / 3.0); assert_eq!(result.as_radians(), std::f32::consts::FRAC_PI_2); ``` There's also a `From<f32>` implementation for `Rotation2d`, which means that methods can still accept radians as floats if the argument uses `impl Into<Rotation2d>`. This means that adding `Rotation2d` shouldn't even be a breaking change. --- ## Changelog - Added `Rotation2d` - Bounding volume methods now take an `impl Into<Rotation2d>` - Gizmo methods with rotation now take an `impl Into<Rotation2d>` ## Future use cases - Collision detection (a type like this is quite essential considering how common vector rotations are) - `Transform` helpers (e.g. return a 2D rotation about the Z axis from a `Transform`) - The rotation used for `Transform2d` (#8268) - More gizmos, maybe meshes... everything in 2D that uses rotation --------- Co-authored-by: Tristan Guichaoua <33934311+tguichaoua@users.noreply.github.com> Co-authored-by: Robert Walter <robwalter96@gmail.com> Co-authored-by: IQuick 143 <IQuick143cz@gmail.com>
2024-03-11 19:11:57 +00:00
mod rotation2d;
}
Implement the `AnimationGraph`, allowing for multiple animations to be blended together. (#11989) This is an implementation of RFC #51: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md Note that the implementation strategy is different from the one outlined in that RFC, because two-phase animation has now landed. # Objective Bevy needs animation blending. The RFC for this is [RFC 51]. ## Solution This is an implementation of the RFC. Note that the implementation strategy is different from the one outlined there, because two-phase animation has now landed. This is just a draft to get the conversation started. Currently we're missing a few things: - [x] A fully-fleshed-out mechanism for transitions - [x] A serialization format for `AnimationGraph`s - [x] Examples are broken, other than `animated_fox` - [x] Documentation --- ## Changelog ### Added * The `AnimationPlayer` has been reworked to support blending multiple animations together through an `AnimationGraph`, and as such will no longer function unless a `Handle<AnimationGraph>` has been added to the entity containing the player. See [RFC 51] for more details. * Transition functionality has moved from the `AnimationPlayer` to a new component, `AnimationTransitions`, which works in tandem with the `AnimationGraph`. ## Migration Guide * `AnimationPlayer`s can no longer play animations by themselves and need to be paired with a `Handle<AnimationGraph>`. Code that was using `AnimationPlayer` to play animations will need to create an `AnimationGraph` asset first, add a node for the clip (or clips) you want to play, and then supply the index of that node to the `AnimationPlayer`'s `play` method. * The `AnimationPlayer::play_with_transition()` method has been removed and replaced with the `AnimationTransitions` component. If you were previously using `AnimationPlayer::play_with_transition()`, add all animations that you were playing to the `AnimationGraph`, and create an `AnimationTransitions` component to manage the blending between them. [RFC 51]: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md --------- Co-authored-by: Rob Parrett <robparrett@gmail.com>
2024-03-07 20:22:42 +00:00
#[cfg(feature = "petgraph")]
mod petgraph;
2020-11-28 00:39:59 +00:00
#[cfg(feature = "smallvec")]
mod smallvec;
#[cfg(feature = "smol_str")]
mod smol_str;
2020-11-28 00:39:59 +00:00
mod std;
#[cfg(feature = "uuid")]
mod uuid;
2020-11-28 00:39:59 +00:00
}
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
mod enums;
2020-11-28 00:39:59 +00:00
pub mod serde;
add `#[reflect(Default)]` to create default value for reflected types (#3733) ### Problem It currently isn't possible to construct the default value of a reflected type. Because of that, it isn't possible to use `add_component` of `ReflectComponent` to add a new component to an entity because you can't know what the initial value should be. ### Solution 1. add `ReflectDefault` type ```rust #[derive(Clone)] pub struct ReflectDefault { default: fn() -> Box<dyn Reflect>, } impl ReflectDefault { pub fn default(&self) -> Box<dyn Reflect> { (self.default)() } } impl<T: Reflect + Default> FromType<T> for ReflectDefault { fn from_type() -> Self { ReflectDefault { default: || Box::new(T::default()), } } } ``` 2. add `#[reflect(Default)]` to all component types that implement `Default` and are user facing (so not `ComputedSize`, `CubemapVisibleEntities` etc.) This makes it possible to add the default value of a component to an entity without any compile-time information: ```rust fn main() { let mut app = App::new(); app.register_type::<Camera>(); let type_registry = app.world.get_resource::<TypeRegistry>().unwrap(); let type_registry = type_registry.read(); let camera_registration = type_registry.get(std::any::TypeId::of::<Camera>()).unwrap(); let reflect_default = camera_registration.data::<ReflectDefault>().unwrap(); let reflect_component = camera_registration .data::<ReflectComponent>() .unwrap() .clone(); let default = reflect_default.default(); drop(type_registry); let entity = app.world.spawn().id(); reflect_component.add_component(&mut app.world, entity, &*default); let camera = app.world.entity(entity).get::<Camera>().unwrap(); dbg!(&camera); } ``` ### Open questions - should we have `ReflectDefault` or `ReflectFromWorld` or both?
2022-05-03 19:20:13 +00:00
pub mod std_traits;
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
pub mod utility;
add `#[reflect(Default)]` to create default value for reflected types (#3733) ### Problem It currently isn't possible to construct the default value of a reflected type. Because of that, it isn't possible to use `add_component` of `ReflectComponent` to add a new component to an entity because you can't know what the initial value should be. ### Solution 1. add `ReflectDefault` type ```rust #[derive(Clone)] pub struct ReflectDefault { default: fn() -> Box<dyn Reflect>, } impl ReflectDefault { pub fn default(&self) -> Box<dyn Reflect> { (self.default)() } } impl<T: Reflect + Default> FromType<T> for ReflectDefault { fn from_type() -> Self { ReflectDefault { default: || Box::new(T::default()), } } } ``` 2. add `#[reflect(Default)]` to all component types that implement `Default` and are user facing (so not `ComputedSize`, `CubemapVisibleEntities` etc.) This makes it possible to add the default value of a component to an entity without any compile-time information: ```rust fn main() { let mut app = App::new(); app.register_type::<Camera>(); let type_registry = app.world.get_resource::<TypeRegistry>().unwrap(); let type_registry = type_registry.read(); let camera_registration = type_registry.get(std::any::TypeId::of::<Camera>()).unwrap(); let reflect_default = camera_registration.data::<ReflectDefault>().unwrap(); let reflect_component = camera_registration .data::<ReflectComponent>() .unwrap() .clone(); let default = reflect_default.default(); drop(type_registry); let entity = app.world.spawn().id(); reflect_component.add_component(&mut app.world, entity, &*default); let camera = app.world.entity(entity).get::<Camera>().unwrap(); dbg!(&camera); } ``` ### Open questions - should we have `ReflectDefault` or `ReflectFromWorld` or both?
2022-05-03 19:20:13 +00:00
2020-11-28 00:39:59 +00:00
pub mod prelude {
add `#[reflect(Default)]` to create default value for reflected types (#3733) ### Problem It currently isn't possible to construct the default value of a reflected type. Because of that, it isn't possible to use `add_component` of `ReflectComponent` to add a new component to an entity because you can't know what the initial value should be. ### Solution 1. add `ReflectDefault` type ```rust #[derive(Clone)] pub struct ReflectDefault { default: fn() -> Box<dyn Reflect>, } impl ReflectDefault { pub fn default(&self) -> Box<dyn Reflect> { (self.default)() } } impl<T: Reflect + Default> FromType<T> for ReflectDefault { fn from_type() -> Self { ReflectDefault { default: || Box::new(T::default()), } } } ``` 2. add `#[reflect(Default)]` to all component types that implement `Default` and are user facing (so not `ComputedSize`, `CubemapVisibleEntities` etc.) This makes it possible to add the default value of a component to an entity without any compile-time information: ```rust fn main() { let mut app = App::new(); app.register_type::<Camera>(); let type_registry = app.world.get_resource::<TypeRegistry>().unwrap(); let type_registry = type_registry.read(); let camera_registration = type_registry.get(std::any::TypeId::of::<Camera>()).unwrap(); let reflect_default = camera_registration.data::<ReflectDefault>().unwrap(); let reflect_component = camera_registration .data::<ReflectComponent>() .unwrap() .clone(); let default = reflect_default.default(); drop(type_registry); let entity = app.world.spawn().id(); reflect_component.add_component(&mut app.world, entity, &*default); let camera = app.world.entity(entity).get::<Camera>().unwrap(); dbg!(&camera); } ``` ### Open questions - should we have `ReflectDefault` or `ReflectFromWorld` or both?
2022-05-03 19:20:13 +00:00
pub use crate::std_traits::*;
#[doc(hidden)]
2020-11-28 00:39:59 +00:00
pub use crate::{
reflect_trait, FromReflect, GetField, GetPath, GetTupleStructField, Reflect,
ReflectDeserialize, ReflectFromReflect, ReflectPath, ReflectSerialize, Struct, TupleStruct,
TypePath,
2020-11-28 00:39:59 +00:00
};
}
pub use array::*;
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
pub use enums::*;
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
pub use fields::*;
bevy_reflect: Add `ReflectFromReflect` (v2) (#6245) # Objective Resolves #4597 (based on the work from #6056 and a refresh of #4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed #4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open #4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-12-11 17:52:48 +00:00
pub use from_reflect::*;
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pub use list::*;
pub use map::*;
pub use path::*;
pub use reflect::*;
pub use struct_trait::*;
pub use tuple::*;
2020-11-28 00:39:59 +00:00
pub use tuple_struct::*;
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
pub use type_info::*;
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
pub use type_path::*;
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pub use type_registry::*;
pub use bevy_reflect_derive::*;
pub use erased_serde;
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
extern crate alloc;
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
/// Exports used by the reflection macros.
///
/// These are not meant to be used directly and are subject to breaking changes.
#[doc(hidden)]
pub mod __macro_exports {
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
use crate::{
DynamicArray, DynamicEnum, DynamicList, DynamicMap, DynamicStruct, DynamicTuple,
DynamicTupleStruct, GetTypeRegistration, TypeRegistry,
};
/// A wrapper trait around [`GetTypeRegistration`].
///
/// This trait is used by the derive macro to recursively register all type dependencies.
/// It's used instead of `GetTypeRegistration` directly to avoid making dynamic types also
/// implement `GetTypeRegistration` in order to be used as active fields.
///
/// This trait has a blanket implementation for all types that implement `GetTypeRegistration`
/// and manual implementations for all dynamic types (which simply do nothing).
pub trait RegisterForReflection {
#[allow(unused_variables)]
fn __register(registry: &mut TypeRegistry) {}
}
impl<T: GetTypeRegistration> RegisterForReflection for T {
fn __register(registry: &mut TypeRegistry) {
registry.register::<T>();
}
}
impl RegisterForReflection for DynamicEnum {}
impl RegisterForReflection for DynamicTupleStruct {}
impl RegisterForReflection for DynamicStruct {}
impl RegisterForReflection for DynamicMap {}
impl RegisterForReflection for DynamicList {}
impl RegisterForReflection for DynamicArray {}
impl RegisterForReflection for DynamicTuple {}
}
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#[cfg(test)]
#[allow(clippy::disallowed_types, clippy::approx_constant)]
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mod tests {
use ::serde::{de::DeserializeSeed, Deserialize, Serialize};
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use bevy_utils::HashMap;
use ron::{
ser::{to_string_pretty, PrettyConfig},
Deserializer,
};
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
use static_assertions::{assert_impl_all, assert_not_impl_all};
use std::{
any::TypeId,
borrow::Cow,
fmt::{Debug, Formatter},
marker::PhantomData,
};
2020-11-28 00:39:59 +00:00
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
use super::prelude::*;
2020-11-28 00:39:59 +00:00
use super::*;
use crate as bevy_reflect;
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
use crate::serde::{ReflectSerializer, UntypedReflectDeserializer};
bevy_reflect: Opt-out attribute for `TypePath` (#9140) # Objective Fixes #9094 ## Solution Takes a bit from [this](https://github.com/bevyengine/bevy/issues/9094#issuecomment-1629333851) comment as well as a [comment](https://discord.com/channels/691052431525675048/1002362493634629796/1128024873260810271) from @soqb. This allows users to opt-out of the `TypePath` implementation that is automatically generated by the `Reflect` derive macro, allowing custom `TypePath` implementations. ```rust #[derive(Reflect)] #[reflect(type_path = false)] struct Foo<T> { #[reflect(ignore)] _marker: PhantomData<T>, } struct NotTypePath; impl<T: 'static> TypePath for Foo<T> { fn type_path() -> &'static str { std::any::type_name::<Self>() } fn short_type_path() -> &'static str { static CELL: GenericTypePathCell = GenericTypePathCell::new(); CELL.get_or_insert::<Self, _>(|| { bevy_utils::get_short_name(std::any::type_name::<Self>()) }) } fn crate_name() -> Option<&'static str> { Some("my_crate") } fn module_path() -> Option<&'static str> { Some("my_crate::foo") } fn type_ident() -> Option<&'static str> { Some("Foo") } } // Can use `TypePath` let _ = <Foo<NotTypePath> as TypePath>::type_path(); // Can register the type let mut registry = TypeRegistry::default(); registry.register::<Foo<NotTypePath>>(); ``` #### Type Path Stability The stability of type paths mainly come into play during serialization. If a type is moved between builds, an unstable type path may become invalid. Users that opt-out of `TypePath` and rely on something like `std::any::type_name` as in the example above, should be aware that this solution removes the stability guarantees. Deserialization thus expects that type to never move. If it does, then the serialized type paths will need to be updated accordingly. If a user depends on stability, they will need to implement that stability logic manually (probably by looking at the expanded output of a typical `Reflect`/`TypePath` derive). This could be difficult for type parameters that don't/can't implement `TypePath`, and will need to make heavy use of string parsing and manipulation to achieve the same effect (alternatively, they can choose to simply exclude any type parameter that doesn't implement `TypePath`). --- ## Changelog - Added the `#[reflect(type_path = false)]` attribute to opt out of the `TypePath` impl when deriving `Reflect` --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-08-10 00:37:56 +00:00
use crate::utility::GenericTypePathCell;
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#[test]
fn reflect_struct() {
#[derive(Reflect)]
struct Foo {
a: u32,
b: f32,
c: Bar,
}
#[derive(Reflect)]
struct Bar {
x: u32,
}
let mut foo = Foo {
a: 42,
b: 3.14,
c: Bar { x: 1 },
};
let a = *foo.get_field::<u32>("a").unwrap();
assert_eq!(a, 42);
*foo.get_field_mut::<u32>("a").unwrap() += 1;
assert_eq!(foo.a, 43);
let bar = foo.get_field::<Bar>("c").unwrap();
assert_eq!(bar.x, 1);
// nested retrieval
let c = foo.field("c").unwrap();
if let ReflectRef::Struct(value) = c.reflect_ref() {
assert_eq!(*value.get_field::<u32>("x").unwrap(), 1);
} else {
panic!("Expected a struct.");
2020-11-28 00:39:59 +00:00
}
// patch Foo with a dynamic struct
let mut dynamic_struct = DynamicStruct::default();
dynamic_struct.insert("a", 123u32);
dynamic_struct.insert("should_be_ignored", 456);
foo.apply(&dynamic_struct);
assert_eq!(foo.a, 123);
}
#[test]
fn reflect_map() {
#[derive(Reflect, Hash)]
#[reflect(Hash)]
struct Foo {
a: u32,
b: String,
}
let key_a = Foo {
a: 1,
b: "k1".to_string(),
};
let key_b = Foo {
a: 1,
b: "k1".to_string(),
};
let key_c = Foo {
a: 3,
b: "k3".to_string(),
};
let mut map = DynamicMap::default();
map.insert(key_a, 10u32);
assert_eq!(10, *map.get(&key_b).unwrap().downcast_ref::<u32>().unwrap());
assert!(map.get(&key_c).is_none());
*map.get_mut(&key_b).unwrap().downcast_mut::<u32>().unwrap() = 20;
assert_eq!(20, *map.get(&key_b).unwrap().downcast_ref::<u32>().unwrap());
}
#[test]
#[allow(clippy::disallowed_types)]
2020-11-28 00:39:59 +00:00
fn reflect_unit_struct() {
#[derive(Reflect)]
struct Foo(u32, u64);
let mut foo = Foo(1, 2);
assert_eq!(1, *foo.get_field::<u32>(0).unwrap());
assert_eq!(2, *foo.get_field::<u64>(1).unwrap());
let mut patch = DynamicTupleStruct::default();
patch.insert(3u32);
patch.insert(4u64);
assert_eq!(3, *patch.field(0).unwrap().downcast_ref::<u32>().unwrap());
assert_eq!(4, *patch.field(1).unwrap().downcast_ref::<u64>().unwrap());
foo.apply(&patch);
assert_eq!(3, foo.0);
assert_eq!(4, foo.1);
let mut iter = patch.iter_fields();
assert_eq!(3, *iter.next().unwrap().downcast_ref::<u32>().unwrap());
assert_eq!(4, *iter.next().unwrap().downcast_ref::<u64>().unwrap());
}
#[test]
#[should_panic(expected = "the given key does not support hashing")]
fn reflect_map_no_hash() {
#[derive(Reflect)]
struct Foo {
a: u32,
}
let foo = Foo { a: 1 };
let mut map = DynamicMap::default();
map.insert(foo, 10u32);
}
#[test]
fn reflect_ignore() {
#[derive(Reflect)]
struct Foo {
a: u32,
#[reflect(ignore)]
_b: u32,
}
let foo = Foo { a: 1, _b: 2 };
let values: Vec<u32> = foo
.iter_fields()
.map(|value| *value.downcast_ref::<u32>().unwrap())
.collect();
assert_eq!(values, vec![1]);
}
bevy_reflect: Add `ReflectFromReflect` (v2) (#6245) # Objective Resolves #4597 (based on the work from #6056 and a refresh of #4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed #4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open #4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-12-11 17:52:48 +00:00
#[test]
fn should_call_from_reflect_dynamically() {
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect)]
bevy_reflect: Add `ReflectFromReflect` (v2) (#6245) # Objective Resolves #4597 (based on the work from #6056 and a refresh of #4147) When using reflection, we may often end up in a scenario where we have a Dynamic representing a certain type. Unfortunately, we can't just call `MyType::from_reflect` as we do not have knowledge of the concrete type (`MyType`) at runtime. Such scenarios happen when we call `Reflect::clone_value`, use the reflection deserializers, or create the Dynamic type ourselves. ## Solution Add a `ReflectFromReflect` type data struct. This struct allows us to easily convert Dynamic representations of our types into their respective concrete instances. ```rust #[derive(Reflect, FromReflect)] #[reflect(FromReflect)] // <- Register `ReflectFromReflect` struct MyStruct(String); let type_id = TypeId::of::<MyStruct>(); // Register our type let mut registry = TypeRegistry::default(); registry.register::<MyStruct>(); // Create a concrete instance let my_struct = MyStruct("Hello world".to_string()); // `Reflect::clone_value` will generate a `DynamicTupleStruct` for tuple struct types let dynamic_value: Box<dyn Reflect> = my_struct.clone_value(); assert!(!dynamic_value.is::<MyStruct>()); // Get the `ReflectFromReflect` type data from the registry let rfr: &ReflectFromReflect = registry .get_type_data::<ReflectFromReflect>(type_id) .unwrap(); // Call `FromReflect::from_reflect` on our Dynamic value let concrete_value: Box<dyn Reflect> = rfr.from_reflect(&dynamic_value); assert!(concrete_value.is::<MyStruct>()); ``` ### Why this PR? ###### Why now? The three main reasons I closed #4147 were that: 1. Registering `ReflectFromReflect` is clunky (deriving `FromReflect` *and* registering `ReflectFromReflect`) 2. The ecosystem and Bevy itself didn't seem to pay much attention to deriving `FromReflect` 3. I didn't see a lot of desire from the community for such a feature However, as time has passed it seems 2 and 3 are not really true anymore. Bevy is internally adding lots more `FromReflect` derives, which should make this feature all the more useful. Additionally, I have seen a growing number of people look for something like `ReflectFromReflect`. I think 1 is still an issue, but not a horrible one. Plus it could be made much, much better using #6056. And I think splitting this feature out of #6056 could lead to #6056 being adopted sooner (or at least make the need more clear to users). ###### Why not just re-open #4147? The main reason is so that this PR can garner more attention than simply re-opening the old one. This helps bring fresh eyes to the PR for potentially more perspectives/reviews. --- ## Changelog * Added `ReflectFromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-12-11 17:52:48 +00:00
struct MyStruct {
foo: usize,
}
// Register
let mut registry = TypeRegistry::default();
registry.register::<MyStruct>();
// Get type data
let type_id = TypeId::of::<MyStruct>();
let rfr = registry
.get_type_data::<ReflectFromReflect>(type_id)
.expect("the FromReflect trait should be registered");
// Call from_reflect
let mut dynamic_struct = DynamicStruct::default();
dynamic_struct.insert("foo", 123usize);
let reflected = rfr
.from_reflect(&dynamic_struct)
.expect("the type should be properly reflected");
// Assert
let expected = MyStruct { foo: 123 };
assert!(expected
.reflect_partial_eq(reflected.as_ref())
.unwrap_or_default());
let not_expected = MyStruct { foo: 321 };
assert!(!not_expected
.reflect_partial_eq(reflected.as_ref())
.unwrap_or_default());
}
bevy_reflect: Fix ignored/skipped field order (#7575) # Objective Fixes #5101 Alternative to #6511 ## Solution Corrected the behavior for ignored fields in `FromReflect`, which was previously using the incorrect field indexes. Similarly, fields marked with `#[reflect(skip_serializing)]` no longer break when using `FromReflect` after deserialization. This was done by modifying `SerializationData` to store a function pointer that can later be used to generate a default instance of the skipped field during deserialization. The function pointer points to a function generated by the derive macro using the behavior designated by `#[reflect(default)]` (or just `Default` if none provided). The entire output of the macro is now wrapped in an [unnamed constant](https://doc.rust-lang.org/stable/reference/items/constant-items.html#unnamed-constant) which keeps this behavior hygienic. #### Rationale The biggest downside to this approach is that it requires fields marked `#[reflect(skip_serializing)]` to provide the ability to create a default instance— either via a `Default` impl or by specifying a custom one. While this isn't great, I think it might be justified by the fact that we really need to create this value when using `FromReflect` on a deserialized object. And we need to do this _during_ deserialization because after that (at least for tuples and tuple structs) we lose information about which field is which: _"is the value at index 1 in this `DynamicTupleStruct` the actual value for index 1 or is it really the value for index 2 since index 1 is skippable...?"_ #### Alternatives An alternative would be to store `Option<Box<dyn Reflect>>` within `DynamicTuple` and `DynamicTupleStruct` instead of just `Box<dyn Reflect>`. This would allow us to insert "empty"/"missing" fields during deserialization, thus saving the positional information of the skipped fields. However, this may require changing the API of `Tuple` and `TupleStruct` such that they can account for their dynamic counterparts returning `None` for a skipped field. In practice this would probably mean exposing the `Option`-ness of the dynamics onto implementors via methods like `Tuple::drain` or `TupleStruct::field`. Personally, I think requiring `Default` would be better than muddying up the API to account for these special cases. But I'm open to trying out this other approach if the community feels that it's better. --- ## Changelog ### Public Changes #### Fixed - The behaviors of `#[reflect(ignore)]` and `#[reflect(skip_serializing)]` are no longer dependent on field order #### Changed - Fields marked with `#[reflect(skip_serializing)]` now need to either implement `Default` or specify a custom default function using `#[reflect(default = "path::to::some_func")]` - Deserializing a type with fields marked `#[reflect(skip_serializing)]` will now include that field initialized to its specified default value - `SerializationData::new` now takes the new `SkippedField` struct along with the skipped field index - Renamed `SerializationData::is_ignored_field` to `SerializationData::is_field_skipped` #### Added - Added `SkippedField` struct - Added methods `SerializationData::generate_default` and `SerializationData::iter_skipped` ### Internal Changes #### Changed - Replaced `members_to_serialization_denylist` and `BitSet<u32>` with `SerializationDataDef` - The `Reflect` derive is more hygienic as it now outputs within an [unnamed constant](https://doc.rust-lang.org/stable/reference/items/constant-items.html#unnamed-constant) - `StructField::index` has been split up into `StructField::declaration_index` and `StructField::reflection_index` #### Removed - Removed `bitset` dependency ## Migration Guide * Fields marked `#[reflect(skip_serializing)]` now must implement `Default` or specify a custom default function with `#[reflect(default = "path::to::some_func")]` ```rust #[derive(Reflect)] struct MyStruct { #[reflect(skip_serializing)] #[reflect(default = "get_foo_default")] foo: Foo, // <- `Foo` does not impl `Default` so requires a custom function #[reflect(skip_serializing)] bar: Bar, // <- `Bar` impls `Default` } #[derive(Reflect)] struct Foo(i32); #[derive(Reflect, Default)] struct Bar(i32); fn get_foo_default() -> Foo { Foo(123) } ``` * `SerializationData::new` has been changed to expect an iterator of `(usize, SkippedField)` rather than one of just `usize` ```rust // BEFORE SerializationData::new([0, 3].into_iter()); // AFTER SerializationData::new([ (0, SkippedField::new(field_0_default_fn)), (3, SkippedField::new(field_3_default_fn)), ].into_iter()); ``` * `Serialization::is_ignored_field` has been renamed to `Serialization::is_field_skipped` * Fields marked `#[reflect(skip_serializing)]` are now included in deserialization output. This may affect logic that expected those fields to be absent.
2023-10-22 12:43:31 +00:00
#[test]
fn from_reflect_should_allow_ignored_unnamed_fields() {
#[derive(Reflect, Eq, PartialEq, Debug)]
struct MyTupleStruct(i8, #[reflect(ignore)] i16, i32);
let expected = MyTupleStruct(1, 0, 3);
let mut dyn_tuple_struct = DynamicTupleStruct::default();
dyn_tuple_struct.insert(1_i8);
dyn_tuple_struct.insert(3_i32);
let my_tuple_struct = <MyTupleStruct as FromReflect>::from_reflect(&dyn_tuple_struct);
assert_eq!(Some(expected), my_tuple_struct);
#[derive(Reflect, Eq, PartialEq, Debug)]
enum MyEnum {
Tuple(i8, #[reflect(ignore)] i16, i32),
}
let expected = MyEnum::Tuple(1, 0, 3);
let mut dyn_tuple = DynamicTuple::default();
dyn_tuple.insert(1_i8);
dyn_tuple.insert(3_i32);
let mut dyn_enum = DynamicEnum::default();
dyn_enum.set_variant("Tuple", dyn_tuple);
let my_enum = <MyEnum as FromReflect>::from_reflect(&dyn_enum);
assert_eq!(Some(expected), my_enum);
}
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
#[test]
fn from_reflect_should_use_default_field_attributes() {
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Debug)]
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
struct MyStruct {
// Use `Default::default()`
// Note that this isn't an ignored field
#[reflect(default)]
foo: String,
// Use `get_bar_default()`
#[reflect(ignore)]
#[reflect(default = "get_bar_default")]
bar: NotReflect,
// Ensure attributes can be combined
#[reflect(ignore, default = "get_bar_default")]
baz: NotReflect,
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
}
#[derive(Eq, PartialEq, Debug)]
struct NotReflect(usize);
fn get_bar_default() -> NotReflect {
NotReflect(123)
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
}
let expected = MyStruct {
foo: String::default(),
bar: NotReflect(123),
baz: NotReflect(123),
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
};
let dyn_struct = DynamicStruct::default();
let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct);
assert_eq!(Some(expected), my_struct);
}
bevy_reflect: Allow `#[reflect(default)]` on enum variant fields (#8514) # Objective When using `FromReflect`, fields can be optionally left out if they are marked with `#[reflect(default)]`. This is very handy for working with serialized data as giant structs only need to list a subset of defined fields in order to be constructed. <details> <summary>Example</summary> Take the following struct: ```rust #[derive(Reflect, FromReflect)] struct Foo { #[reflect(default)] a: usize, #[reflect(default)] b: usize, #[reflect(default)] c: usize, #[reflect(default)] d: usize, } ``` Since all the fields are default-able, we can successfully call `FromReflect` on deserialized data like: ```rust ( "foo::Foo": ( // Only set `b` and default the rest b: 123 ) ) ``` </details> Unfortunately, this does not work with fields in enum variants. Marking a variant field as `#[reflect(default)]` does nothing when calling `FromReflect`. ## Solution Allow enum variant fields to define a default value using `#[reflect(default)]`. ### `#[reflect(Default)]` One thing that structs and tuple structs can do is use their `Default` implementation when calling `FromReflect`. Adding `#[reflect(Default)]` to the struct or tuple struct both registers `ReflectDefault` and alters the `FromReflect` implementation to use `Default` to generate any missing fields. This works well enough for structs and tuple structs, but for enums it's not as simple. Since the `Default` implementation for an enum only covers a single variant, it's not as intuitive as to what the behavior will be. And (imo) it feels weird that we would be able to specify default values in this way for one variant but not the others. Because of this, I chose to not implement that behavior here. However, I'm open to adding it in if anyone feels otherwise. --- ## Changelog - Allow enum variant fields to define a default value using `#[reflect(default)]`
2023-05-29 15:29:29 +00:00
#[test]
fn from_reflect_should_use_default_variant_field_attributes() {
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Debug)]
bevy_reflect: Allow `#[reflect(default)]` on enum variant fields (#8514) # Objective When using `FromReflect`, fields can be optionally left out if they are marked with `#[reflect(default)]`. This is very handy for working with serialized data as giant structs only need to list a subset of defined fields in order to be constructed. <details> <summary>Example</summary> Take the following struct: ```rust #[derive(Reflect, FromReflect)] struct Foo { #[reflect(default)] a: usize, #[reflect(default)] b: usize, #[reflect(default)] c: usize, #[reflect(default)] d: usize, } ``` Since all the fields are default-able, we can successfully call `FromReflect` on deserialized data like: ```rust ( "foo::Foo": ( // Only set `b` and default the rest b: 123 ) ) ``` </details> Unfortunately, this does not work with fields in enum variants. Marking a variant field as `#[reflect(default)]` does nothing when calling `FromReflect`. ## Solution Allow enum variant fields to define a default value using `#[reflect(default)]`. ### `#[reflect(Default)]` One thing that structs and tuple structs can do is use their `Default` implementation when calling `FromReflect`. Adding `#[reflect(Default)]` to the struct or tuple struct both registers `ReflectDefault` and alters the `FromReflect` implementation to use `Default` to generate any missing fields. This works well enough for structs and tuple structs, but for enums it's not as simple. Since the `Default` implementation for an enum only covers a single variant, it's not as intuitive as to what the behavior will be. And (imo) it feels weird that we would be able to specify default values in this way for one variant but not the others. Because of this, I chose to not implement that behavior here. However, I'm open to adding it in if anyone feels otherwise. --- ## Changelog - Allow enum variant fields to define a default value using `#[reflect(default)]`
2023-05-29 15:29:29 +00:00
enum MyEnum {
Foo(#[reflect(default)] String),
Bar {
#[reflect(default = "get_baz_default")]
#[reflect(ignore)]
baz: usize,
},
}
fn get_baz_default() -> usize {
123
}
let expected = MyEnum::Foo(String::default());
let dyn_enum = DynamicEnum::new("Foo", DynamicTuple::default());
let my_enum = <MyEnum as FromReflect>::from_reflect(&dyn_enum);
assert_eq!(Some(expected), my_enum);
let expected = MyEnum::Bar {
baz: get_baz_default(),
};
let dyn_enum = DynamicEnum::new("Bar", DynamicStruct::default());
let my_enum = <MyEnum as FromReflect>::from_reflect(&dyn_enum);
assert_eq!(Some(expected), my_enum);
}
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
#[test]
fn from_reflect_should_use_default_container_attribute() {
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Debug)]
bevy_reflect: Add `#[reflect(default)]` attribute for `FromReflect` (#4140) # Objective Currently, `FromReflect` makes a couple assumptions: * Ignored fields must implement `Default` * Active fields must implement `FromReflect` * The reflected must be fully populated for active fields (can't use an empty `DynamicStruct`) However, one or both of these requirements might be unachievable, such as for external types. In these cases, it might be nice to tell `FromReflect` to use a custom default. ## Solution Added the `#[reflect(default)]` derive helper attribute. This attribute can be applied to any field (ignored or not) and will allow a default value to be specified in place of the regular `from_reflect()` call. It takes two forms: `#[reflect(default)]` and `#[reflect(default = "some_func")]`. The former specifies that `Default::default()` should be used while the latter specifies that `some_func()` should be used. This is pretty much [how serde does it](https://serde.rs/field-attrs.html#default). ### Example ```rust #[derive(Reflect, FromReflect)] struct MyStruct { // Use `Default::default()` #[reflect(default)] foo: String, // Use `get_bar_default()` #[reflect(default = "get_bar_default")] #[reflect(ignore)] bar: usize, } fn get_bar_default() -> usize { 123 } ``` ### Active Fields As an added benefit, this also allows active fields to be completely missing from their dynamic object. This is because the attribute tells `FromReflect` how to handle missing active fields (it still tries to use `from_reflect` first so the `FromReflect` trait is still required). ```rust let dyn_struct = DynamicStruct::default(); // We can do this without actually including the active fields since they have `#[reflect(default)]` let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` ### Container Defaults Also, with the addition of #3733, people will likely start adding `#[reflect(Default)]` to their types now. Just like with the fields, we can use this to mark the entire container as "defaultable". This grants us the ability to completely remove the field markers altogether if our type implements `Default` (and we're okay with fields using that instead of their own `Default` impls): ```rust #[derive(Reflect, FromReflect)] #[reflect(Default)] struct MyStruct { foo: String, #[reflect(ignore)] bar: usize, } impl Default for MyStruct { fn default() -> Self { Self { foo: String::from("Hello"), bar: 123, } } } // Again, we can now construct this from nothing pretty much let dyn_struct = DynamicStruct::default(); let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct); ``` Now if _any_ field is missing when using `FromReflect`, we simply fallback onto the container's `Default` implementation. This behavior can be completely overridden on a per-field basis, of course, by simply defining those same field attributes like before. ### Related * #3733 * #1395 * #2377 --- ## Changelog * Added `#[reflect(default)]` field attribute for `FromReflect` * Allows missing fields to be given a default value when using `FromReflect` * `#[reflect(default)]` - Use the field's `Default` implementation * `#[reflect(default = "some_fn")]` - Use a custom function to get the default value * Allow `#[reflect(Default)]` to have a secondary usage as a container attribute * Allows missing fields to be given a default value based on the container's `Default` impl when using `FromReflect` Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 19:06:25 +00:00
#[reflect(Default)]
struct MyStruct {
foo: String,
#[reflect(ignore)]
bar: usize,
}
impl Default for MyStruct {
fn default() -> Self {
Self {
foo: String::from("Hello"),
bar: 123,
}
}
}
let expected = MyStruct {
foo: String::from("Hello"),
bar: 123,
};
let dyn_struct = DynamicStruct::default();
let my_struct = <MyStruct as FromReflect>::from_reflect(&dyn_struct);
assert_eq!(Some(expected), my_struct);
}
2020-11-28 00:39:59 +00:00
#[test]
fn reflect_complex_patch() {
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Debug)]
Reflection cleanup (#1536) This is an effort to provide the correct `#[reflect_value(...)]` attributes where they are needed. Supersedes #1533 and resolves #1528. --- I am working under the following assumptions (thanks to @bjorn3 and @Davier for advice here): - Any `enum` that derives `Reflect` and one or more of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } needs a `#[reflect_value(...)]` attribute containing the same subset of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } that is present on the derive. - Same as above for `struct` and `#[reflect(...)]`, respectively. - If a `struct` is used as a component, it should also have `#[reflect(Component)]` - All reflected types should be registered in their plugins I treated the following as components (added `#[reflect(Component)]` if necessary): - `bevy_render` - `struct RenderLayers` - `bevy_transform` - `struct GlobalTransform` - `struct Parent` - `struct Transform` - `bevy_ui` - `struct Style` Not treated as components: - `bevy_math` - `struct Size<T>` - `struct Rect<T>` - Note: The updates for `Size<T>` and `Rect<T>` in `bevy::math::geometry` required using @Davier's suggestion to add `+ PartialEq` to the trait bound. I then registered the specific types used over in `bevy_ui` such as `Size<Val>`, etc. in `bevy_ui`'s plugin, since `bevy::math` does not contain a plugin. - `bevy_render` - `struct Color` - `struct PipelineSpecialization` - `struct ShaderSpecialization` - `enum PrimitiveTopology` - `enum IndexFormat` Not Addressed: - I am not searching for components in Bevy that are _not_ reflected. So if there are components that are not reflected that should be reflected, that will need to be figured out in another PR. - I only added `#[reflect(...)]` or `#[reflect_value(...)]` entries for the set of four traits { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } _if they were derived via `#[derive(...)]`_. I did not look for manual trait implementations of the same set of four, nor did I consider any traits outside the four. Are those other possibilities something that needs to be looked into?
2021-03-09 23:39:41 +00:00
#[reflect(PartialEq)]
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struct Foo {
a: u32,
#[reflect(ignore)]
_b: u32,
c: Vec<isize>,
d: HashMap<usize, i8>,
e: Bar,
f: (i32, Vec<isize>, Bar),
g: Vec<(Baz, HashMap<usize, Bar>)>,
h: [u32; 2],
2020-11-28 00:39:59 +00:00
}
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Clone, Debug)]
Reflection cleanup (#1536) This is an effort to provide the correct `#[reflect_value(...)]` attributes where they are needed. Supersedes #1533 and resolves #1528. --- I am working under the following assumptions (thanks to @bjorn3 and @Davier for advice here): - Any `enum` that derives `Reflect` and one or more of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } needs a `#[reflect_value(...)]` attribute containing the same subset of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } that is present on the derive. - Same as above for `struct` and `#[reflect(...)]`, respectively. - If a `struct` is used as a component, it should also have `#[reflect(Component)]` - All reflected types should be registered in their plugins I treated the following as components (added `#[reflect(Component)]` if necessary): - `bevy_render` - `struct RenderLayers` - `bevy_transform` - `struct GlobalTransform` - `struct Parent` - `struct Transform` - `bevy_ui` - `struct Style` Not treated as components: - `bevy_math` - `struct Size<T>` - `struct Rect<T>` - Note: The updates for `Size<T>` and `Rect<T>` in `bevy::math::geometry` required using @Davier's suggestion to add `+ PartialEq` to the trait bound. I then registered the specific types used over in `bevy_ui` such as `Size<Val>`, etc. in `bevy_ui`'s plugin, since `bevy::math` does not contain a plugin. - `bevy_render` - `struct Color` - `struct PipelineSpecialization` - `struct ShaderSpecialization` - `enum PrimitiveTopology` - `enum IndexFormat` Not Addressed: - I am not searching for components in Bevy that are _not_ reflected. So if there are components that are not reflected that should be reflected, that will need to be figured out in another PR. - I only added `#[reflect(...)]` or `#[reflect_value(...)]` entries for the set of four traits { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } _if they were derived via `#[derive(...)]`_. I did not look for manual trait implementations of the same set of four, nor did I consider any traits outside the four. Are those other possibilities something that needs to be looked into?
2021-03-09 23:39:41 +00:00
#[reflect(PartialEq)]
2020-11-28 00:39:59 +00:00
struct Bar {
x: u32,
}
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[derive(Reflect, Eq, PartialEq, Debug)]
struct Baz(String);
2020-11-28 00:39:59 +00:00
let mut hash_map = HashMap::default();
hash_map.insert(1, 1);
hash_map.insert(2, 2);
let mut hash_map_baz = HashMap::default();
hash_map_baz.insert(1, Bar { x: 0 });
2020-11-28 00:39:59 +00:00
let mut foo = Foo {
a: 1,
_b: 1,
c: vec![1, 2],
d: hash_map,
e: Bar { x: 1 },
f: (1, vec![1, 2], Bar { x: 1 }),
g: vec![(Baz("string".to_string()), hash_map_baz)],
h: [2; 2],
2020-11-28 00:39:59 +00:00
};
let mut foo_patch = DynamicStruct::default();
foo_patch.insert("a", 2u32);
foo_patch.insert("b", 2u32); // this should be ignored
let mut list = DynamicList::default();
list.push(3isize);
list.push(4isize);
list.push(5isize);
bevy_reflect: Decouple `List` and `Array` traits (#7467) # Objective Resolves #7121 ## Solution Decouples `List` and `Array` by removing `Array` as a supertrait of `List`. Additionally, similar methods from `Array` have been added to `List` so that their usages can remain largely unchanged. #### Possible Alternatives ##### `Sequence` My guess for why we originally made `List` a subtrait of `Array` is that they share a lot of common operations. We could potentially move these overlapping methods to a `Sequence` (name taken from #7059) trait and make that a supertrait of both. This would allow functions to contain logic that simply operates on a sequence rather than "list vs array". However, this means that we'd need to add methods for converting to a `dyn Sequence`. It also might be confusing since we wouldn't add a `ReflectRef::Sequence` or anything like that. Is such a trait worth adding (either in this PR or a followup one)? --- ## Changelog - Removed `Array` as supertrait of `List` - Added methods to `List` that were previously provided by `Array` ## Migration Guide The `List` trait is no longer dependent on `Array`. Implementors of `List` can remove the `Array` impl and move its methods into the `List` impl (with only a couple tweaks). ```rust // BEFORE impl Array for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ArrayIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicArray {/* ... */} } impl List for Foo { fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } // AFTER impl List for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ListIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } ``` Some other small tweaks that will need to be made include: - Use `ListIter` for `List::iter` instead of `ArrayIter` (the return type from `Array::iter`) - Replace `array_hash` with `list_hash` in `Reflect::reflect_hash` for implementors of `List`
2023-02-13 21:07:53 +00:00
foo_patch.insert("c", list.clone_dynamic());
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let mut map = DynamicMap::default();
map.insert(2usize, 3i8);
map.insert(3usize, 4i8);
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foo_patch.insert("d", map);
let mut bar_patch = DynamicStruct::default();
bar_patch.insert("x", 2u32);
foo_patch.insert("e", bar_patch.clone_dynamic());
let mut tuple = DynamicTuple::default();
tuple.insert(2i32);
tuple.insert(list);
tuple.insert(bar_patch);
foo_patch.insert("f", tuple);
2020-11-28 00:39:59 +00:00
let mut composite = DynamicList::default();
composite.push({
let mut tuple = DynamicTuple::default();
tuple.insert({
let mut tuple_struct = DynamicTupleStruct::default();
tuple_struct.insert("new_string".to_string());
tuple_struct
});
tuple.insert({
let mut map = DynamicMap::default();
map.insert(1usize, {
let mut struct_ = DynamicStruct::default();
struct_.insert("x", 7u32);
struct_
});
map
});
tuple
});
foo_patch.insert("g", composite);
let array = DynamicArray::from_vec(vec![2u32, 2u32]);
foo_patch.insert("h", array);
2020-11-28 00:39:59 +00:00
foo.apply(&foo_patch);
let mut hash_map = HashMap::default();
hash_map.insert(1, 1);
hash_map.insert(2, 3);
hash_map.insert(3, 4);
let mut hash_map_baz = HashMap::default();
hash_map_baz.insert(1, Bar { x: 7 });
2020-11-28 00:39:59 +00:00
let expected_foo = Foo {
a: 2,
_b: 1,
c: vec![3, 4, 5],
d: hash_map,
e: Bar { x: 2 },
f: (2, vec![3, 4, 5], Bar { x: 2 }),
g: vec![(Baz("new_string".to_string()), hash_map_baz.clone())],
h: [2; 2],
2020-11-28 00:39:59 +00:00
};
assert_eq!(foo, expected_foo);
let new_foo = Foo::from_reflect(&foo_patch)
.expect("error while creating a concrete type from a dynamic type");
let mut hash_map = HashMap::default();
hash_map.insert(2, 3);
hash_map.insert(3, 4);
let expected_new_foo = Foo {
a: 2,
_b: 0,
c: vec![3, 4, 5],
d: hash_map,
e: Bar { x: 2 },
f: (2, vec![3, 4, 5], Bar { x: 2 }),
g: vec![(Baz("new_string".to_string()), hash_map_baz)],
h: [2; 2],
};
assert_eq!(new_foo, expected_new_foo);
2020-11-28 00:39:59 +00:00
}
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
#[test]
fn should_auto_register_fields() {
#[derive(Reflect)]
struct Foo {
bar: Bar,
}
#[derive(Reflect)]
enum Bar {
Variant(Baz),
}
#[derive(Reflect)]
struct Baz(usize);
// === Basic === //
let mut registry = TypeRegistry::empty();
registry.register::<Foo>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `Foo`"
);
// === Option === //
let mut registry = TypeRegistry::empty();
registry.register::<Option<Foo>>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `Option<Foo>`"
);
// === Tuple === //
let mut registry = TypeRegistry::empty();
registry.register::<(Foo, Foo)>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `(Foo, Foo)`"
);
// === Array === //
let mut registry = TypeRegistry::empty();
registry.register::<[Foo; 3]>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `[Foo; 3]`"
);
// === Vec === //
let mut registry = TypeRegistry::empty();
registry.register::<Vec<Foo>>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `Vec<Foo>`"
);
// === HashMap === //
let mut registry = TypeRegistry::empty();
registry.register::<HashMap<i32, Foo>>();
assert!(
registry.contains(TypeId::of::<Bar>()),
"registry should contain auto-registered `Bar` from `HashMap<i32, Foo>`"
);
}
#[test]
fn should_allow_dynamic_fields() {
#[derive(Reflect)]
#[reflect(from_reflect = false)]
struct MyStruct(
DynamicEnum,
DynamicTupleStruct,
DynamicStruct,
DynamicMap,
DynamicList,
DynamicArray,
DynamicTuple,
i32,
);
assert_impl_all!(MyStruct: Reflect, GetTypeRegistration);
let mut registry = TypeRegistry::empty();
registry.register::<MyStruct>();
assert_eq!(2, registry.iter().count());
assert!(registry.contains(TypeId::of::<MyStruct>()));
assert!(registry.contains(TypeId::of::<i32>()));
}
#[test]
fn should_not_auto_register_existing_types() {
#[derive(Reflect)]
struct Foo {
bar: Bar,
}
#[derive(Reflect, Default)]
struct Bar(usize);
let mut registry = TypeRegistry::empty();
registry.register::<Bar>();
registry.register_type_data::<Bar, ReflectDefault>();
registry.register::<Foo>();
assert!(
registry
.get_type_data::<ReflectDefault>(TypeId::of::<Bar>())
.is_some(),
"registry should contain existing registration for `Bar`"
);
}
2020-11-28 00:39:59 +00:00
#[test]
fn reflect_serialize() {
#[derive(Reflect)]
struct Foo {
a: u32,
#[reflect(ignore)]
_b: u32,
c: Vec<isize>,
d: HashMap<usize, i8>,
e: Bar,
f: String,
g: (i32, Vec<isize>, Bar),
h: [u32; 2],
2020-11-28 00:39:59 +00:00
}
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
#[derive(Reflect, Serialize, Deserialize)]
#[reflect(Serialize, Deserialize)]
2020-11-28 00:39:59 +00:00
struct Bar {
x: u32,
}
let mut hash_map = HashMap::default();
hash_map.insert(1, 1);
hash_map.insert(2, 2);
let foo = Foo {
a: 1,
_b: 1,
c: vec![1, 2],
d: hash_map,
e: Bar { x: 1 },
f: "hi".to_string(),
g: (1, vec![1, 2], Bar { x: 1 }),
h: [2; 2],
2020-11-28 00:39:59 +00:00
};
let mut registry = TypeRegistry::default();
registry.register::<u32>();
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
registry.register::<i8>();
registry.register::<i32>();
2020-11-28 00:39:59 +00:00
registry.register::<usize>();
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
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registry.register::<isize>();
registry.register::<Foo>();
2020-11-28 00:39:59 +00:00
registry.register::<Bar>();
registry.register::<String>();
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
registry.register::<Vec<isize>>();
registry.register::<HashMap<usize, i8>>();
registry.register::<(i32, Vec<isize>, Bar)>();
registry.register::<[u32; 2]>();
2020-11-28 00:39:59 +00:00
let serializer = ReflectSerializer::new(&foo, &registry);
let serialized = to_string_pretty(&serializer, PrettyConfig::default()).unwrap();
let mut deserializer = Deserializer::from_str(&serialized).unwrap();
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
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let reflect_deserializer = UntypedReflectDeserializer::new(&registry);
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let value = reflect_deserializer.deserialize(&mut deserializer).unwrap();
let dynamic_struct = value.take::<DynamicStruct>().unwrap();
assert!(foo.reflect_partial_eq(&dynamic_struct).unwrap());
2020-11-28 00:39:59 +00:00
}
#[test]
fn reflect_downcast() {
#[derive(Reflect, Clone, Debug, PartialEq)]
struct Bar {
y: u8,
}
#[derive(Reflect, Clone, Debug, PartialEq)]
struct Foo {
x: i32,
s: String,
b: Bar,
u: usize,
t: ([f32; 3], String),
v: Cow<'static, str>,
w: Cow<'static, [u8]>,
}
let foo = Foo {
x: 123,
s: "String".to_string(),
b: Bar { y: 255 },
u: 1111111111111,
t: ([3.0, 2.0, 1.0], "Tuple String".to_string()),
v: Cow::Owned("Cow String".to_string()),
w: Cow::Owned(vec![1, 2, 3]),
};
let foo2: Box<dyn Reflect> = Box::new(foo.clone());
assert_eq!(foo, *foo2.downcast::<Foo>().unwrap());
}
bevy_reflect: Get owned fields (#5728) # Objective Sometimes it's useful to be able to retrieve all the fields of a container type so that they may be processed separately. With reflection, however, we typically only have access to references. The only alternative is to "clone" the value using `Reflect::clone_value`. This, however, returns a Dynamic type in most cases. The solution there would be to use `FromReflect` instead, but this also has a problem in that it means we need to add `FromReflect` as an additional bound. ## Solution Add a `drain` method to all container traits. This returns a `Vec<Box<dyn Reflect>>` (except for `Map` which returns `Vec<(Box<dyn Reflect>, Box<dyn Reflect>)>`). This allows us to do things a lot simpler. For example, if we finished processing a struct and just need a particular value: ```rust // === OLD === // /// May or may not return a Dynamic*** value (even if `container` wasn't a `DynamicStruct`) fn get_output(container: Box<dyn Struct>, output_index: usize) -> Box<dyn Reflect> { container.field_at(output_index).unwrap().clone_value() } // === NEW === // /// Returns _exactly_ whatever was in the given struct fn get_output(container: Box<dyn Struct>, output_index: usize) -> Box<dyn Reflect> { container.drain().remove(output_index).unwrap() } ``` ### Discussion * Is `drain` the best method name? It makes sense that it "drains" all the fields and that it consumes the container in the process, but I'm open to alternatives. --- ## Changelog * Added a `drain` method to the following traits: * `Struct` * `TupleStruct` * `Tuple` * `Array` * `List` * `Map` * `Enum`
2022-08-30 21:20:58 +00:00
#[test]
fn should_drain_fields() {
let array_value: Box<dyn Array> = Box::new([123_i32, 321_i32]);
let fields = array_value.drain();
assert!(fields[0].reflect_partial_eq(&123_i32).unwrap_or_default());
assert!(fields[1].reflect_partial_eq(&321_i32).unwrap_or_default());
let list_value: Box<dyn List> = Box::new(vec![123_i32, 321_i32]);
let fields = list_value.drain();
assert!(fields[0].reflect_partial_eq(&123_i32).unwrap_or_default());
assert!(fields[1].reflect_partial_eq(&321_i32).unwrap_or_default());
let tuple_value: Box<dyn Tuple> = Box::new((123_i32, 321_i32));
let fields = tuple_value.drain();
assert!(fields[0].reflect_partial_eq(&123_i32).unwrap_or_default());
assert!(fields[1].reflect_partial_eq(&321_i32).unwrap_or_default());
let map_value: Box<dyn Map> = Box::new(HashMap::from([(123_i32, 321_i32)]));
let fields = map_value.drain();
assert!(fields[0].0.reflect_partial_eq(&123_i32).unwrap_or_default());
assert!(fields[0].1.reflect_partial_eq(&321_i32).unwrap_or_default());
}
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#[test]
fn reflect_take() {
#[derive(Reflect, Debug, PartialEq)]
Reflection cleanup (#1536) This is an effort to provide the correct `#[reflect_value(...)]` attributes where they are needed. Supersedes #1533 and resolves #1528. --- I am working under the following assumptions (thanks to @bjorn3 and @Davier for advice here): - Any `enum` that derives `Reflect` and one or more of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } needs a `#[reflect_value(...)]` attribute containing the same subset of { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } that is present on the derive. - Same as above for `struct` and `#[reflect(...)]`, respectively. - If a `struct` is used as a component, it should also have `#[reflect(Component)]` - All reflected types should be registered in their plugins I treated the following as components (added `#[reflect(Component)]` if necessary): - `bevy_render` - `struct RenderLayers` - `bevy_transform` - `struct GlobalTransform` - `struct Parent` - `struct Transform` - `bevy_ui` - `struct Style` Not treated as components: - `bevy_math` - `struct Size<T>` - `struct Rect<T>` - Note: The updates for `Size<T>` and `Rect<T>` in `bevy::math::geometry` required using @Davier's suggestion to add `+ PartialEq` to the trait bound. I then registered the specific types used over in `bevy_ui` such as `Size<Val>`, etc. in `bevy_ui`'s plugin, since `bevy::math` does not contain a plugin. - `bevy_render` - `struct Color` - `struct PipelineSpecialization` - `struct ShaderSpecialization` - `enum PrimitiveTopology` - `enum IndexFormat` Not Addressed: - I am not searching for components in Bevy that are _not_ reflected. So if there are components that are not reflected that should be reflected, that will need to be figured out in another PR. - I only added `#[reflect(...)]` or `#[reflect_value(...)]` entries for the set of four traits { `Serialize`, `Deserialize`, `PartialEq`, `Hash` } _if they were derived via `#[derive(...)]`_. I did not look for manual trait implementations of the same set of four, nor did I consider any traits outside the four. Are those other possibilities something that needs to be looked into?
2021-03-09 23:39:41 +00:00
#[reflect(PartialEq)]
2020-11-28 00:39:59 +00:00
struct Bar {
x: u32,
}
let x: Box<dyn Reflect> = Box::new(Bar { x: 2 });
let y = x.take::<Bar>().unwrap();
assert_eq!(y, Bar { x: 2 });
}
#[test]
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
fn not_dynamic_names() {
let list = Vec::<usize>::new();
bevy_reflect: Decouple `List` and `Array` traits (#7467) # Objective Resolves #7121 ## Solution Decouples `List` and `Array` by removing `Array` as a supertrait of `List`. Additionally, similar methods from `Array` have been added to `List` so that their usages can remain largely unchanged. #### Possible Alternatives ##### `Sequence` My guess for why we originally made `List` a subtrait of `Array` is that they share a lot of common operations. We could potentially move these overlapping methods to a `Sequence` (name taken from #7059) trait and make that a supertrait of both. This would allow functions to contain logic that simply operates on a sequence rather than "list vs array". However, this means that we'd need to add methods for converting to a `dyn Sequence`. It also might be confusing since we wouldn't add a `ReflectRef::Sequence` or anything like that. Is such a trait worth adding (either in this PR or a followup one)? --- ## Changelog - Removed `Array` as supertrait of `List` - Added methods to `List` that were previously provided by `Array` ## Migration Guide The `List` trait is no longer dependent on `Array`. Implementors of `List` can remove the `Array` impl and move its methods into the `List` impl (with only a couple tweaks). ```rust // BEFORE impl Array for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ArrayIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicArray {/* ... */} } impl List for Foo { fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } // AFTER impl List for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ListIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } ``` Some other small tweaks that will need to be made include: - Use `ListIter` for `List::iter` instead of `ArrayIter` (the return type from `Array::iter`) - Replace `array_hash` with `list_hash` in `Reflect::reflect_hash` for implementors of `List`
2023-02-13 21:07:53 +00:00
let dyn_list = list.clone_dynamic();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(dyn_list.reflect_type_path(), Vec::<usize>::type_path());
let array = [b'0'; 4];
bevy_reflect: Decouple `List` and `Array` traits (#7467) # Objective Resolves #7121 ## Solution Decouples `List` and `Array` by removing `Array` as a supertrait of `List`. Additionally, similar methods from `Array` have been added to `List` so that their usages can remain largely unchanged. #### Possible Alternatives ##### `Sequence` My guess for why we originally made `List` a subtrait of `Array` is that they share a lot of common operations. We could potentially move these overlapping methods to a `Sequence` (name taken from #7059) trait and make that a supertrait of both. This would allow functions to contain logic that simply operates on a sequence rather than "list vs array". However, this means that we'd need to add methods for converting to a `dyn Sequence`. It also might be confusing since we wouldn't add a `ReflectRef::Sequence` or anything like that. Is such a trait worth adding (either in this PR or a followup one)? --- ## Changelog - Removed `Array` as supertrait of `List` - Added methods to `List` that were previously provided by `Array` ## Migration Guide The `List` trait is no longer dependent on `Array`. Implementors of `List` can remove the `Array` impl and move its methods into the `List` impl (with only a couple tweaks). ```rust // BEFORE impl Array for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ArrayIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicArray {/* ... */} } impl List for Foo { fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } // AFTER impl List for Foo { fn get(&self, index: usize) -> Option<&dyn Reflect> {/* ... */} fn get_mut(&mut self, index: usize) -> Option<&mut dyn Reflect> {/* ... */} fn insert(&mut self, index: usize, element: Box<dyn Reflect>) {/* ... */} fn remove(&mut self, index: usize) -> Box<dyn Reflect> {/* ... */} fn push(&mut self, value: Box<dyn Reflect>) {/* ... */} fn pop(&mut self) -> Option<Box<dyn Reflect>> {/* ... */} fn len(&self) -> usize {/* ... */} fn is_empty(&self) -> bool {/* ... */} fn iter(&self) -> ListIter {/* ... */} fn drain(self: Box<Self>) -> Vec<Box<dyn Reflect>> {/* ... */} fn clone_dynamic(&self) -> DynamicList {/* ... */} } ``` Some other small tweaks that will need to be made include: - Use `ListIter` for `List::iter` instead of `ArrayIter` (the return type from `Array::iter`) - Replace `array_hash` with `list_hash` in `Reflect::reflect_hash` for implementors of `List`
2023-02-13 21:07:53 +00:00
let dyn_array = array.clone_dynamic();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(dyn_array.reflect_type_path(), <[u8; 4]>::type_path());
let map = HashMap::<usize, String>::default();
let dyn_map = map.clone_dynamic();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(
dyn_map.reflect_type_path(),
HashMap::<usize, String>::type_path()
);
let tuple = (0usize, "1".to_string(), 2.0f32);
let mut dyn_tuple = tuple.clone_dynamic();
dyn_tuple.insert::<usize>(3);
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(
dyn_tuple.reflect_type_path(),
<(usize, String, f32, usize)>::type_path()
);
#[derive(Reflect)]
struct TestStruct {
a: usize,
}
let struct_ = TestStruct { a: 0 };
let dyn_struct = struct_.clone_dynamic();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(dyn_struct.reflect_type_path(), TestStruct::type_path());
#[derive(Reflect)]
struct TestTupleStruct(usize);
let tuple_struct = TestTupleStruct(0);
let dyn_tuple_struct = tuple_struct.clone_dynamic();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_ne!(
dyn_tuple_struct.reflect_type_path(),
TestTupleStruct::type_path()
);
}
bevy_reflect: Add `as_reflect` and `as_reflect_mut` (#4350) # Objective Trait objects that have `Reflect` as a supertrait cannot be upcast to a `dyn Reflect`. Attempting something like: ```rust trait MyTrait: Reflect { // ... } fn foo(value: &dyn MyTrait) { let reflected = value as &dyn Reflect; // Error! // ... } ``` Results in `error[E0658]: trait upcasting coercion is experimental`. The reason this is important is that a lot of `bevy_reflect` methods require a `&dyn Reflect`. This is trivial with concrete types, but if we don't know the concrete type (we only have the trait object), we can't use these methods. For example, we couldn't create a `ReflectSerializer` for the type since it expects a `&dyn Reflect` value— even though we should be able to. ## Solution Add `as_reflect` and `as_reflect_mut` to `Reflect` to allow upcasting to a `dyn Reflect`: ```rust trait MyTrait: Reflect { // ... } fn foo(value: &dyn MyTrait) { let reflected = value.as_reflect(); // ... } ``` ## Alternatives We could defer this type of logic to the crate/user. They can add these methods to their trait in the same exact way we do here. The main benefit of doing it ourselves is it makes things convenient for them (especially when using the derive macro). We could also create an `AsReflect` trait with a blanket impl over all reflected types, however, I could not get that to work for trait objects since they aren't sized. --- ## Changelog - Added trait method `Reflect::as_reflect(&self)` - Added trait method `Reflect::as_reflect_mut(&mut self)` ## Migration Guide - Manual implementors of `Reflect` will need to add implementations for the methods above (this should be pretty easy as most cases just need to return `self`)
2022-04-25 13:54:48 +00:00
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
macro_rules! assert_type_paths {
($($ty:ty => $long:literal, $short:literal,)*) => {
$(
assert_eq!(<$ty as TypePath>::type_path(), $long);
assert_eq!(<$ty as TypePath>::short_type_path(), $short);
)*
};
}
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
#[test]
fn reflect_type_path() {
#[derive(TypePath)]
struct Param;
#[derive(TypePath)]
struct Derive;
#[derive(TypePath)]
#[type_path = "my_alias"]
struct DerivePath;
#[derive(TypePath)]
#[type_path = "my_alias"]
#[type_name = "MyDerivePathName"]
struct DerivePathName;
#[derive(TypePath)]
struct DeriveG<T>(PhantomData<T>);
#[derive(TypePath)]
#[type_path = "my_alias"]
struct DerivePathG<T, const N: usize>(PhantomData<T>);
#[derive(TypePath)]
#[type_path = "my_alias"]
#[type_name = "MyDerivePathNameG"]
struct DerivePathNameG<T>(PhantomData<T>);
struct Macro;
impl_type_path!((in my_alias) Macro);
struct MacroName;
impl_type_path!((in my_alias as MyMacroName) MacroName);
struct MacroG<T, const N: usize>(PhantomData<T>);
impl_type_path!((in my_alias) MacroG<T, const N: usize>);
struct MacroNameG<T>(PhantomData<T>);
impl_type_path!((in my_alias as MyMacroNameG) MacroNameG<T>);
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
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assert_type_paths! {
Derive => "bevy_reflect::tests::Derive", "Derive",
DerivePath => "my_alias::DerivePath", "DerivePath",
DerivePathName => "my_alias::MyDerivePathName", "MyDerivePathName",
DeriveG<Param> => "bevy_reflect::tests::DeriveG<bevy_reflect::tests::Param>", "DeriveG<Param>",
DerivePathG<Param, 10> => "my_alias::DerivePathG<bevy_reflect::tests::Param, 10>", "DerivePathG<Param, 10>",
DerivePathNameG<Param> => "my_alias::MyDerivePathNameG<bevy_reflect::tests::Param>", "MyDerivePathNameG<Param>",
Macro => "my_alias::Macro", "Macro",
MacroName => "my_alias::MyMacroName", "MyMacroName",
MacroG<Param, 10> => "my_alias::MacroG<bevy_reflect::tests::Param, 10>", "MacroG<Param, 10>",
MacroNameG<Param> => "my_alias::MyMacroNameG<bevy_reflect::tests::Param>", "MyMacroNameG<Param>",
}
}
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
#[test]
fn std_type_paths() {
#[derive(Clone)]
struct Type;
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
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impl TypePath for Type {
fn type_path() -> &'static str {
// for brevity in tests
"Long"
}
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
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fn short_type_path() -> &'static str {
"Short"
}
}
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_type_paths! {
u8 => "u8", "u8",
Type => "Long", "Short",
&Type => "&Long", "&Short",
[Type] => "[Long]", "[Short]",
&[Type] => "&[Long]", "&[Short]",
[Type; 0] => "[Long; 0]", "[Short; 0]",
[Type; 100] => "[Long; 100]", "[Short; 100]",
() => "()", "()",
(Type,) => "(Long,)", "(Short,)",
(Type, Type) => "(Long, Long)", "(Short, Short)",
(Type, Type, Type) => "(Long, Long, Long)", "(Short, Short, Short)",
Cow<'static, Type> => "alloc::borrow::Cow<Long>", "Cow<Short>",
}
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
}
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
#[test]
fn reflect_type_info() {
// TypeInfo
let info = i32::type_info();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(i32::type_path(), info.type_path());
assert_eq!(TypeId::of::<i32>(), info.type_id());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
// TypeInfo (unsized)
assert_eq!(
TypeId::of::<dyn Reflect>(),
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
<dyn Reflect as Typed>::type_info().type_id()
);
// TypeInfo (instance)
let value: &dyn Reflect = &123_i32;
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<i32>());
// Struct
#[derive(Reflect)]
struct MyStruct {
foo: i32,
bar: usize,
}
let info = MyStruct::type_info();
if let TypeInfo::Struct(info) = info {
assert!(info.is::<MyStruct>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyStruct::type_path(), info.type_path());
assert_eq!(i32::type_path(), info.field("foo").unwrap().type_path());
assert_eq!(TypeId::of::<i32>(), info.field("foo").unwrap().type_id());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.field("foo").unwrap().is::<i32>());
assert_eq!("foo", info.field("foo").unwrap().name());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(usize::type_path(), info.field_at(1).unwrap().type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::Struct`");
}
let value: &dyn Reflect = &MyStruct { foo: 123, bar: 321 };
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyStruct>());
// Struct (generic)
#[derive(Reflect)]
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
struct MyGenericStruct<T> {
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
foo: T,
bar: usize,
}
let info = <MyGenericStruct<i32>>::type_info();
if let TypeInfo::Struct(info) = info {
assert!(info.is::<MyGenericStruct<i32>>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyGenericStruct::<i32>::type_path(), info.type_path());
assert_eq!(i32::type_path(), info.field("foo").unwrap().type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert_eq!("foo", info.field("foo").unwrap().name());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(usize::type_path(), info.field_at(1).unwrap().type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::Struct`");
}
let value: &dyn Reflect = &MyGenericStruct {
foo: String::from("Hello!"),
bar: 321,
};
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyGenericStruct<String>>());
// Tuple Struct
#[derive(Reflect)]
struct MyTupleStruct(usize, i32, MyStruct);
let info = MyTupleStruct::type_info();
if let TypeInfo::TupleStruct(info) = info {
assert!(info.is::<MyTupleStruct>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyTupleStruct::type_path(), info.type_path());
assert_eq!(i32::type_path(), info.field_at(1).unwrap().type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.field_at(1).unwrap().is::<i32>());
} else {
panic!("Expected `TypeInfo::TupleStruct`");
}
// Tuple
type MyTuple = (u32, f32, String);
let info = MyTuple::type_info();
if let TypeInfo::Tuple(info) = info {
assert!(info.is::<MyTuple>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyTuple::type_path(), info.type_path());
assert_eq!(f32::type_path(), info.field_at(1).unwrap().type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::Tuple`");
}
let value: &dyn Reflect = &(123_u32, 1.23_f32, String::from("Hello!"));
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyTuple>());
// List
type MyList = Vec<usize>;
let info = MyList::type_info();
if let TypeInfo::List(info) = info {
assert!(info.is::<MyList>());
assert!(info.item_is::<usize>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyList::type_path(), info.type_path());
assert_eq!(usize::type_path(), info.item_type_path_table().path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::List`");
}
let value: &dyn Reflect = &vec![123_usize];
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyList>());
// List (SmallVec)
#[cfg(feature = "smallvec")]
{
type MySmallVec = smallvec::SmallVec<[String; 2]>;
let info = MySmallVec::type_info();
if let TypeInfo::List(info) = info {
assert!(info.is::<MySmallVec>());
assert!(info.item_is::<String>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MySmallVec::type_path(), info.type_path());
assert_eq!(String::type_path(), info.item_type_path_table().path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::List`");
}
let value: MySmallVec = smallvec::smallvec![String::default(); 2];
let value: &dyn Reflect = &value;
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MySmallVec>());
}
// Array
type MyArray = [usize; 3];
let info = MyArray::type_info();
if let TypeInfo::Array(info) = info {
assert!(info.is::<MyArray>());
assert!(info.item_is::<usize>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyArray::type_path(), info.type_path());
assert_eq!(usize::type_path(), info.item_type_path_table().path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert_eq!(3, info.capacity());
} else {
panic!("Expected `TypeInfo::Array`");
}
let value: &dyn Reflect = &[1usize, 2usize, 3usize];
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyArray>());
// Cow<'static, str>
type MyCowStr = Cow<'static, str>;
let info = MyCowStr::type_info();
if let TypeInfo::Value(info) = info {
assert!(info.is::<MyCowStr>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(std::any::type_name::<MyCowStr>(), info.type_path());
} else {
panic!("Expected `TypeInfo::Value`");
}
let value: &dyn Reflect = &Cow::<'static, str>::Owned("Hello!".to_string());
let info = value.get_represented_type_info().unwrap();
assert!(info.is::<MyCowStr>());
// Cow<'static, [u8]>
type MyCowSlice = Cow<'static, [u8]>;
let info = MyCowSlice::type_info();
if let TypeInfo::List(info) = info {
assert!(info.is::<MyCowSlice>());
assert!(info.item_is::<u8>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(std::any::type_name::<MyCowSlice>(), info.type_path());
assert_eq!(
std::any::type_name::<u8>(),
info.item_type_path_table().path()
);
} else {
panic!("Expected `TypeInfo::List`");
}
let value: &dyn Reflect = &Cow::<'static, [u8]>::Owned(vec![0, 1, 2, 3]);
let info = value.get_represented_type_info().unwrap();
assert!(info.is::<MyCowSlice>());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
// Map
type MyMap = HashMap<usize, f32>;
let info = MyMap::type_info();
if let TypeInfo::Map(info) = info {
assert!(info.is::<MyMap>());
assert!(info.key_is::<usize>());
assert!(info.value_is::<f32>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyMap::type_path(), info.type_path());
assert_eq!(usize::type_path(), info.key_type_path_table().path());
assert_eq!(f32::type_path(), info.value_type_path_table().path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::Map`");
}
let value: &dyn Reflect = &MyMap::new();
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyMap>());
// Value
type MyValue = String;
let info = MyValue::type_info();
if let TypeInfo::Value(info) = info {
assert!(info.is::<MyValue>());
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(MyValue::type_path(), info.type_path());
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
} else {
panic!("Expected `TypeInfo::Value`");
}
let value: &dyn Reflect = &String::from("Hello!");
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
let info = value.get_represented_type_info().unwrap();
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
assert!(info.is::<MyValue>());
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
}
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
#[test]
fn should_permit_higher_ranked_lifetimes() {
#[derive(Reflect)]
bevy_reflect: `FromReflect` Ergonomics Implementation (#6056) # Objective **This implementation is based on https://github.com/bevyengine/rfcs/pull/59.** --- Resolves #4597 Full details and motivation can be found in the RFC, but here's a brief summary. `FromReflect` is a very powerful and important trait within the reflection API. It allows Dynamic types (e.g., `DynamicList`, etc.) to be formed into Real ones (e.g., `Vec<i32>`, etc.). This mainly comes into play concerning deserialization, where the reflection deserializers both return a `Box<dyn Reflect>` that almost always contain one of these Dynamic representations of a Real type. To convert this to our Real type, we need to use `FromReflect`. It also sneaks up in other ways. For example, it's a required bound for `T` in `Vec<T>` so that `Vec<T>` as a whole can be made `FromReflect`. It's also required by all fields of an enum as it's used as part of the `Reflect::apply` implementation. So in other words, much like `GetTypeRegistration` and `Typed`, it is very much a core reflection trait. The problem is that it is not currently treated like a core trait and is not automatically derived alongside `Reflect`. This makes using it a bit cumbersome and easy to forget. ## Solution Automatically derive `FromReflect` when deriving `Reflect`. Users can then choose to opt-out if needed using the `#[reflect(from_reflect = false)]` attribute. ```rust #[derive(Reflect)] struct Foo; #[derive(Reflect)] #[reflect(from_reflect = false)] struct Bar; fn test<T: FromReflect>(value: T) {} test(Foo); // <-- OK test(Bar); // <-- Panic! Bar does not implement trait `FromReflect` ``` #### `ReflectFromReflect` This PR also automatically adds the `ReflectFromReflect` (introduced in #6245) registration to the derived `GetTypeRegistration` impl— if the type hasn't opted out of `FromReflect` of course. <details> <summary><h4>Improved Deserialization</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. And since we can do all the above, we might as well improve deserialization. We can now choose to deserialize into a Dynamic type or automatically convert it using `FromReflect` under the hood. `[Un]TypedReflectDeserializer::new` will now perform the conversion and return the `Box`'d Real type. `[Un]TypedReflectDeserializer::new_dynamic` will work like what we have now and simply return the `Box`'d Dynamic type. ```rust // Returns the Real type let reflect_deserializer = UntypedReflectDeserializer::new(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // Returns the Dynamic type let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` </details> --- ## Changelog * `FromReflect` is now automatically derived within the `Reflect` derive macro * This includes auto-registering `ReflectFromReflect` in the derived `GetTypeRegistration` impl * ~~Renamed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic`, respectively~~ **Descoped** * ~~Changed `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` to automatically convert the deserialized output using `FromReflect`~~ **Descoped** ## Migration Guide * `FromReflect` is now automatically derived within the `Reflect` derive macro. Items with both derives will need to remove the `FromReflect` one. ```rust // OLD #[derive(Reflect, FromReflect)] struct Foo; // NEW #[derive(Reflect)] struct Foo; ``` If using a manual implementation of `FromReflect` and the `Reflect` derive, users will need to opt-out of the automatic implementation. ```rust // OLD #[derive(Reflect)] struct Foo; impl FromReflect for Foo {/* ... */} // NEW #[derive(Reflect)] #[reflect(from_reflect = false)] struct Foo; impl FromReflect for Foo {/* ... */} ``` <details> <summary><h4>Removed Migrations</h4></summary> > **Warning** > This section includes changes that have since been descoped from this PR. They will likely be implemented again in a followup PR. I am mainly leaving these details in for archival purposes, as well as for reference when implementing this logic again. * The reflect deserializers now perform a `FromReflect` conversion internally. The expected output of `TypedReflectDeserializer::new` and `UntypedReflectDeserializer::new` is no longer a Dynamic (e.g., `DynamicList`), but its Real counterpart (e.g., `Vec<i32>`). ```rust let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); let mut deserializer = ron::de::Deserializer::from_str(input)?; // OLD let output: DynamicStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; // NEW let output: SomeStruct = reflect_deserializer.deserialize(&mut deserializer)?.take()?; ``` Alternatively, if this behavior isn't desired, use the `TypedReflectDeserializer::new_dynamic` and `UntypedReflectDeserializer::new_dynamic` methods instead: ```rust // OLD let reflect_deserializer = UntypedReflectDeserializer::new(&registry); // NEW let reflect_deserializer = UntypedReflectDeserializer::new_dynamic(&registry); ``` </details> --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-06-29 01:31:34 +00:00
#[reflect(from_reflect = false)]
struct TestStruct {
#[reflect(ignore)]
_hrl: for<'a> fn(&'a str) -> &'a str,
}
impl Default for TestStruct {
fn default() -> Self {
TestStruct {
_hrl: |input| input,
}
}
}
fn get_type_registration<T: GetTypeRegistration>() {}
get_type_registration::<TestStruct>();
}
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
#[test]
fn should_permit_valid_represented_type_for_dynamic() {
let type_info = <[i32; 2] as Typed>::type_info();
let mut dynamic_array = [123; 2].clone_dynamic();
dynamic_array.set_represented_type(Some(type_info));
}
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
bevy_reflect: Better proxies (#6971) # Objective > This PR is based on discussion from #6601 The Dynamic types (e.g. `DynamicStruct`, `DynamicList`, etc.) act as both: 1. Dynamic containers which may hold any arbitrary data 2. Proxy types which may represent any other type Currently, the only way we can represent the proxy-ness of a Dynamic is by giving it a name. ```rust // This is just a dynamic container let mut data = DynamicStruct::default(); // This is a "proxy" data.set_name(std::any::type_name::<Foo>()); ``` This type name is the only way we check that the given Dynamic is a proxy of some other type. When we need to "assert the type" of a `dyn Reflect`, we call `Reflect::type_name` on it. However, because we're only using a string to denote the type, we run into a few gotchas and limitations. For example, hashing a Dynamic proxy may work differently than the type it proxies: ```rust #[derive(Reflect, Hash)] #[reflect(Hash)] struct Foo(i32); let concrete = Foo(123); let dynamic = concrete.clone_dynamic(); let concrete_hash = concrete.reflect_hash(); let dynamic_hash = dynamic.reflect_hash(); // The hashes are not equal because `concrete` uses its own `Hash` impl // while `dynamic` uses a reflection-based hashing algorithm assert_ne!(concrete_hash, dynamic_hash); ``` Because the Dynamic proxy only knows about the name of the type, it's unaware of any other information about it. This means it also differs on `Reflect::reflect_partial_eq`, and may include ignored or skipped fields in places the concrete type wouldn't. ## Solution Rather than having Dynamics pass along just the type name of proxied types, we can instead have them pass around the `TypeInfo`. Now all Dynamic types contain an `Option<&'static TypeInfo>` rather than a `String`: ```diff pub struct DynamicTupleStruct { - type_name: String, + represented_type: Option<&'static TypeInfo>, fields: Vec<Box<dyn Reflect>>, } ``` By changing `Reflect::get_type_info` to `Reflect::represented_type_info`, hopefully we make this behavior a little clearer. And to account for `None` values on these dynamic types, `Reflect::represented_type_info` now returns `Option<&'static TypeInfo>`. ```rust let mut data = DynamicTupleStruct::default(); // Not proxying any specific type assert!(dyn_tuple_struct.represented_type_info().is_none()); let type_info = <Foo as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); // Alternatively: // let dyn_tuple_struct = foo.clone_dynamic(); // Now we're proxying `Foo` assert!(dyn_tuple_struct.represented_type_info().is_some()); ``` This means that we can have full access to all the static type information for the proxied type. Future work would include transitioning more static type information (trait impls, attributes, etc.) over to the `TypeInfo` so it can actually be utilized by Dynamic proxies. ### Alternatives & Rationale > **Note** > These alternatives were written when this PR was first made using a `Proxy` trait. This trait has since been removed. <details> <summary>View</summary> #### Alternative: The `Proxy<T>` Approach I had considered adding something like a `Proxy<T>` type where `T` would be the Dynamic and would contain the proxied type information. This was nice in that it allows us to explicitly determine whether something is a proxy or not at a type level. `Proxy<DynamicStruct>` proxies a struct. Makes sense. The reason I didn't go with this approach is because (1) tuples, (2) complexity, and (3) `PartialReflect`. The `DynamicTuple` struct allows us to represent tuples at runtime. It also allows us to do something you normally can't with tuples: add new fields. Because of this, adding a field immediately invalidates the proxy (e.g. our info for `(i32, i32)` doesn't apply to `(i32, i32, NewField)`). By going with this PR's approach, we can just remove the type info on `DynamicTuple` when that happens. However, with the `Proxy<T>` approach, it becomes difficult to represent this behavior— we'd have to completely control how we access data for `T` for each `T`. Secondly, it introduces some added complexities (aside from the manual impls for each `T`). Does `Proxy<T>` impl `Reflect`? Likely yes, if we want to represent it as `dyn Reflect`. What `TypeInfo` do we give it? How would we forward reflection methods to the inner type (remember, we don't have specialization)? How do we separate this from Dynamic types? And finally, how do all this in a way that's both logical and intuitive for users? Lastly, introducing a `Proxy` trait rather than a `Proxy<T>` struct is actually more inline with the [Unique Reflect RFC](https://github.com/bevyengine/rfcs/pull/56). In a way, the `Proxy` trait is really one part of the `PartialReflect` trait introduced in that RFC (it's technically not in that RFC but it fits well with it), where the `PartialReflect` serves as a way for proxies to work _like_ concrete types without having full access to everything a concrete `Reflect` type can do. This would help bridge the gap between the current state of the crate and the implementation of that RFC. All that said, this is still a viable solution. If the community believes this is the better path forward, then we can do that instead. These were just my reasons for not initially going with it in this PR. #### Alternative: The Type Registry Approach The `Proxy` trait is great and all, but how does it solve the original problem? Well, it doesn't— yet! The goal would be to start moving information from the derive macro and its attributes to the generated `TypeInfo` since these are known statically and shouldn't change. For example, adding `ignored: bool` to `[Un]NamedField` or a list of impls. However, there is another way of storing this information. This is, of course, one of the uses of the `TypeRegistry`. If we're worried about Dynamic proxies not aligning with their concrete counterparts, we could move more type information to the registry and require its usage. For example, we could replace `Reflect::reflect_hash(&self)` with `Reflect::reflect_hash(&self, registry: &TypeRegistry)`. That's not the _worst_ thing in the world, but it is an ergonomics loss. Additionally, other attributes may have their own requirements, further restricting what's possible without the registry. The `Reflect::apply` method will require the registry as well now. Why? Well because the `map_apply` function used for the `Reflect::apply` impls on `Map` types depends on `Map::insert_boxed`, which (at least for `DynamicMap`) requires `Reflect::reflect_hash`. The same would apply when adding support for reflection-based diffing, which will require `Reflect::reflect_partial_eq`. Again, this is a totally viable alternative. I just chose not to go with it for the reasons above. If we want to go with it, then we can close this PR and we can pursue this alternative instead. #### Downsides Just to highlight a quick potential downside (likely needs more investigation): retrieving the `TypeInfo` requires acquiring a lock on the `GenericTypeInfoCell` used by the `Typed` impls for generic types (non-generic types use a `OnceBox which should be faster). I am not sure how much of a performance hit that is and will need to run some benchmarks to compare against. </details> ### Open Questions 1. Should we use `Cow<'static, TypeInfo>` instead? I think that might be easier for modding? Perhaps, in that case, we need to update `Typed::type_info` and friends as well? 2. Are the alternatives better than the approach this PR takes? Are there other alternatives? --- ## Changelog ### Changed - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` - This method now returns `Option<&'static TypeInfo>` rather than just `&'static TypeInfo` ### Added - Added `Reflect::is_dynamic` method to indicate when a type is dynamic - Added a `set_represented_type` method on all dynamic types ### Removed - Removed `TypeInfo::Dynamic` (use `Reflect::is_dynamic` instead) - Removed `Typed` impls for all dynamic types ## Migration Guide - The Dynamic types no longer take a string type name. Instead, they require a static reference to `TypeInfo`: ```rust #[derive(Reflect)] struct MyTupleStruct(f32, f32); let mut dyn_tuple_struct = DynamicTupleStruct::default(); dyn_tuple_struct.insert(1.23_f32); dyn_tuple_struct.insert(3.21_f32); // BEFORE: let type_name = std::any::type_name::<MyTupleStruct>(); dyn_tuple_struct.set_name(type_name); // AFTER: let type_info = <MyTupleStruct as Typed>::type_info(); dyn_tuple_struct.set_represented_type(Some(type_info)); ``` - `Reflect::get_type_info` has been renamed to `Reflect::represented_type_info` and now also returns an `Option<&'static TypeInfo>` (instead of just `&'static TypeInfo`): ```rust // BEFORE: let info: &'static TypeInfo = value.get_type_info(); // AFTER: let info: &'static TypeInfo = value.represented_type_info().unwrap(); ``` - `TypeInfo::Dynamic` and `DynamicInfo` has been removed. Use `Reflect::is_dynamic` instead: ```rust // BEFORE: if matches!(value.get_type_info(), TypeInfo::Dynamic) { // ... } // AFTER: if value.is_dynamic() { // ... } ``` --------- Co-authored-by: radiish <cb.setho@gmail.com>
2023-04-26 12:17:46 +00:00
#[test]
#[should_panic(expected = "expected TypeInfo::Array but received")]
fn should_prohibit_invalid_represented_type_for_dynamic() {
let type_info = <(i32, i32) as Typed>::type_info();
let mut dynamic_array = [123; 2].clone_dynamic();
dynamic_array.set_represented_type(Some(type_info));
bevy_reflect: Add statically available type info for reflected types (#4042) # Objective > Resolves #4504 It can be helpful to have access to type information without requiring an instance of that type. Especially for `Reflect`, a lot of the gathered type information is known at compile-time and should not necessarily require an instance. ## Solution Created a dedicated `TypeInfo` enum to store static type information. All types that derive `Reflect` now also implement the newly created `Typed` trait: ```rust pub trait Typed: Reflect { fn type_info() -> &'static TypeInfo; } ``` > Note: This trait was made separate from `Reflect` due to `Sized` restrictions. If you only have access to a `dyn Reflect`, just call `.get_type_info()` on it. This new trait method on `Reflect` should return the same value as if you had called it statically. If all you have is a `TypeId` or type name, you can get the `TypeInfo` directly from the registry using the `TypeRegistry::get_type_info` method (assuming it was registered). ### Usage Below is an example of working with `TypeInfo`. As you can see, we don't have to generate an instance of `MyTupleStruct` in order to get this information. ```rust #[derive(Reflect)] struct MyTupleStruct(usize, i32, MyStruct); let info = MyTupleStruct::type_info(); if let TypeInfo::TupleStruct(info) = info { assert!(info.is::<MyTupleStruct>()); assert_eq!(std::any::type_name::<MyTupleStruct>(), info.type_name()); assert!(info.field_at(1).unwrap().is::<i32>()); } else { panic!("Expected `TypeInfo::TupleStruct`"); } ``` ### Manual Implementations It's not recommended to manually implement `Typed` yourself, but if you must, you can use the `TypeInfoCell` to automatically create and manage the static `TypeInfo`s for you (which is very helpful for blanket/generic impls): ```rust use bevy_reflect::{Reflect, TupleStructInfo, TypeInfo, UnnamedField}; use bevy_reflect::utility::TypeInfoCell; struct Foo<T: Reflect>(T); impl<T: Reflect> Typed for Foo<T> { fn type_info() -> &'static TypeInfo { static CELL: TypeInfoCell = TypeInfoCell::generic(); CELL.get_or_insert::<Self, _>(|| { let fields = [UnnamedField::new::<T>()]; let info = TupleStructInfo::new::<Self>(&fields); TypeInfo::TupleStruct(info) }) } } ``` ## Benefits One major benefit is that this opens the door to other serialization methods. Since we can get all the type info at compile time, we can know how to properly deserialize something like: ```rust #[derive(Reflect)] struct MyType { foo: usize, bar: Vec<String> } // RON to be deserialized: ( type: "my_crate::MyType", // <- We now know how to deserialize the rest of this object value: { // "foo" is a value type matching "usize" "foo": 123, // "bar" is a list type matching "Vec<String>" with item type "String" "bar": ["a", "b", "c"] } ) ``` Not only is this more compact, but it has better compatibility (we can change the type of `"foo"` to `i32` without having to update our serialized data). Of course, serialization/deserialization strategies like this may need to be discussed and fully considered before possibly making a change. However, we will be better equipped to do that now that we can access type information right from the registry. ## Discussion Some items to discuss: 1. Duplication. There's a bit of overlap with the existing traits/structs since they require an instance of the type while the type info structs do not (for example, `Struct::field_at(&self, index: usize)` and `StructInfo::field_at(&self, index: usize)`, though only `StructInfo` is accessible without an instance object). Is this okay, or do we want to handle it in another way? 2. Should `TypeInfo::Dynamic` be removed? Since the dynamic types don't have type information available at runtime, we could consider them `TypeInfo::Value`s (or just even just `TypeInfo::Struct`). The intention with `TypeInfo::Dynamic` was to keep the distinction from these dynamic types and actual structs/values since users might incorrectly believe the methods of the dynamic type's info struct would map to some contained data (which isn't possible statically). 4. General usefulness of this change, including missing/unnecessary parts. 5. Possible changes to the scene format? (One possible issue with changing it like in the example above might be that we'd have to be careful when handling generic or trait object types.) ## Compile Tests I ran a few tests to compare compile times (as suggested [here](https://github.com/bevyengine/bevy/pull/4042#discussion_r876408143)). I toggled `Reflect` and `FromReflect` derive macros using `cfg_attr` for both this PR (aa5178e7736a6f8252e10e543e52722107649d3f) and main (c309acd4322b1c3b2089e247a2d28b938eb7b56d). <details> <summary>See More</summary> The test project included 250 of the following structs (as well as a few other structs): ```rust #[derive(Default)] #[cfg_attr(feature = "reflect", derive(Reflect))] #[cfg_attr(feature = "from_reflect", derive(FromReflect))] pub struct Big001 { inventory: Inventory, foo: usize, bar: String, baz: ItemDescriptor, items: [Item; 20], hello: Option<String>, world: HashMap<i32, String>, okay: (isize, usize, /* wesize */), nope: ((String, String), (f32, f32)), blah: Cow<'static, str>, } ``` > I don't know if the compiler can optimize all these duplicate structs away, but I think it's fine either way. We're comparing times, not finding the absolute worst-case time. I only ran each build 3 times using `cargo build --timings` (thank you @devil-ira), each of which were preceeded by a `cargo clean --package bevy_reflect_compile_test`. Here are the times I got: | Test | Test 1 | Test 2 | Test 3 | Average | | -------------------------------- | ------ | ------ | ------ | ------- | | Main | 1.7s | 3.1s | 1.9s | 2.33s | | Main + `Reflect` | 8.3s | 8.6s | 8.1s | 8.33s | | Main + `Reflect` + `FromReflect` | 11.6s | 11.8s | 13.8s | 12.4s | | PR | 3.5s | 1.8s | 1.9s | 2.4s | | PR + `Reflect` | 9.2s | 8.8s | 9.3s | 9.1s | | PR + `Reflect` + `FromReflect` | 12.9s | 12.3s | 12.5s | 12.56s | </details> --- ## Future Work Even though everything could probably be made `const`, we unfortunately can't. This is because `TypeId::of::<T>()` is not yet `const` (see https://github.com/rust-lang/rust/issues/77125). When it does get stabilized, it would probably be worth coming back and making things `const`. Co-authored-by: MrGVSV <49806985+MrGVSV@users.noreply.github.com>
2022-06-09 21:18:15 +00:00
}
#[cfg(feature = "documentation")]
mod docstrings {
use super::*;
#[test]
fn should_not_contain_docs() {
// Regular comments do not count as doc comments,
// and are therefore not reflected.
#[derive(Reflect)]
struct SomeStruct;
let info = <SomeStruct as Typed>::type_info();
assert_eq!(None, info.docs());
/*
* Block comments do not count as doc comments,
* and are therefore not reflected.
*/
#[derive(Reflect)]
struct SomeOtherStruct;
let info = <SomeOtherStruct as Typed>::type_info();
assert_eq!(None, info.docs());
}
#[test]
fn should_contain_docs() {
/// Some struct.
///
/// # Example
///
/// ```ignore (This is only used for a unit test, no need to doc test)
/// let some_struct = SomeStruct;
/// ```
#[derive(Reflect)]
struct SomeStruct;
let info = <SomeStruct as Typed>::type_info();
assert_eq!(
Some(" Some struct.\n\n # Example\n\n ```ignore (This is only used for a unit test, no need to doc test)\n let some_struct = SomeStruct;\n ```"),
info.docs()
);
#[doc = "The compiler automatically converts `///`-style comments into `#[doc]` attributes."]
#[doc = "Of course, you _could_ use the attribute directly if you wanted to."]
#[doc = "Both will be reflected."]
#[derive(Reflect)]
struct SomeOtherStruct;
let info = <SomeOtherStruct as Typed>::type_info();
assert_eq!(
Some("The compiler automatically converts `///`-style comments into `#[doc]` attributes.\nOf course, you _could_ use the attribute directly if you wanted to.\nBoth will be reflected."),
info.docs()
);
/// Some tuple struct.
#[derive(Reflect)]
struct SomeTupleStruct(usize);
let info = <SomeTupleStruct as Typed>::type_info();
assert_eq!(Some(" Some tuple struct."), info.docs());
/// Some enum.
#[derive(Reflect)]
enum SomeEnum {
Foo,
}
let info = <SomeEnum as Typed>::type_info();
assert_eq!(Some(" Some enum."), info.docs());
#[derive(Clone)]
struct SomePrimitive;
impl_reflect_value!(
/// Some primitive for which we have attributed custom documentation.
reflect: stable type path v2 (#7184) # Objective - Introduce a stable alternative to [`std::any::type_name`](https://doc.rust-lang.org/std/any/fn.type_name.html). - Rewrite of #5805 with heavy inspiration in design. - On the path to #5830. - Part of solving #3327. ## Solution - Add a `TypePath` trait for static stable type path/name information. - Add a `TypePath` derive macro. - Add a `impl_type_path` macro for implementing internal and foreign types in `bevy_reflect`. --- ## Changelog - Added `TypePath` trait. - Added `DynamicTypePath` trait and `get_type_path` method to `Reflect`. - Added a `TypePath` derive macro. - Added a `bevy_reflect::impl_type_path` for implementing `TypePath` on internal and foreign types in `bevy_reflect`. - Changed `bevy_reflect::utility::(Non)GenericTypeInfoCell` to `(Non)GenericTypedCell<T>` which allows us to be generic over both `TypeInfo` and `TypePath`. - `TypePath` is now a supertrait of `Asset`, `Material` and `Material2d`. - `impl_reflect_struct` needs a `#[type_path = "..."]` attribute to be specified. - `impl_reflect_value` needs to either specify path starting with a double colon (`::core::option::Option`) or an `in my_crate::foo` declaration. - Added `bevy_reflect_derive::ReflectTypePath`. - Most uses of `Ident` in `bevy_reflect_derive` changed to use `ReflectTypePath`. ## Migration Guide - Implementors of `Asset`, `Material` and `Material2d` now also need to derive `TypePath`. - Manual implementors of `Reflect` will need to implement the new `get_type_path` method. ## Open Questions - [x] ~This PR currently does not migrate any usages of `std::any::type_name` to use `bevy_reflect::TypePath` to ease the review process. Should it?~ Migration will be left to a follow-up PR. - [ ] This PR adds a lot of `#[derive(TypePath)]` and `T: TypePath` to satisfy new bounds, mostly when deriving `TypeUuid`. Should we make `TypePath` a supertrait of `TypeUuid`? [Should we remove `TypeUuid` in favour of `TypePath`?](https://github.com/bevyengine/bevy/pull/5805/files/2afbd855327c4b68e0a6b6f03118f289988441a4#r961067892)
2023-06-05 20:31:20 +00:00
(in bevy_reflect::tests) SomePrimitive
);
let info = <SomePrimitive as Typed>::type_info();
assert_eq!(
Some(" Some primitive for which we have attributed custom documentation."),
info.docs()
);
}
#[test]
fn fields_should_contain_docs() {
#[derive(Reflect)]
struct SomeStruct {
/// The name
name: String,
/// The index
index: usize,
// Not documented...
data: Vec<i32>,
}
let info = <SomeStruct as Typed>::type_info();
if let TypeInfo::Struct(info) = info {
let mut fields = info.iter();
assert_eq!(Some(" The name"), fields.next().unwrap().docs());
assert_eq!(Some(" The index"), fields.next().unwrap().docs());
assert_eq!(None, fields.next().unwrap().docs());
} else {
panic!("expected struct info");
}
}
#[test]
fn variants_should_contain_docs() {
#[derive(Reflect)]
enum SomeEnum {
// Not documented...
Nothing,
/// Option A
A(
/// Index
usize,
),
/// Option B
B {
/// Name
name: String,
},
}
let info = <SomeEnum as Typed>::type_info();
if let TypeInfo::Enum(info) = info {
let mut variants = info.iter();
assert_eq!(None, variants.next().unwrap().docs());
let variant = variants.next().unwrap();
assert_eq!(Some(" Option A"), variant.docs());
if let VariantInfo::Tuple(variant) = variant {
let field = variant.field_at(0).unwrap();
assert_eq!(Some(" Index"), field.docs());
} else {
panic!("expected tuple variant")
}
let variant = variants.next().unwrap();
assert_eq!(Some(" Option B"), variant.docs());
if let VariantInfo::Struct(variant) = variant {
let field = variant.field_at(0).unwrap();
assert_eq!(Some(" Name"), field.docs());
} else {
panic!("expected struct variant")
}
} else {
panic!("expected enum info");
}
}
}
#[test]
fn into_reflect() {
trait TestTrait: Reflect {}
#[derive(Reflect)]
struct TestStruct;
impl TestTrait for TestStruct {}
let trait_object: Box<dyn TestTrait> = Box::new(TestStruct);
// Should compile:
let _ = trait_object.into_reflect();
}
bevy_reflect: Add `as_reflect` and `as_reflect_mut` (#4350) # Objective Trait objects that have `Reflect` as a supertrait cannot be upcast to a `dyn Reflect`. Attempting something like: ```rust trait MyTrait: Reflect { // ... } fn foo(value: &dyn MyTrait) { let reflected = value as &dyn Reflect; // Error! // ... } ``` Results in `error[E0658]: trait upcasting coercion is experimental`. The reason this is important is that a lot of `bevy_reflect` methods require a `&dyn Reflect`. This is trivial with concrete types, but if we don't know the concrete type (we only have the trait object), we can't use these methods. For example, we couldn't create a `ReflectSerializer` for the type since it expects a `&dyn Reflect` value— even though we should be able to. ## Solution Add `as_reflect` and `as_reflect_mut` to `Reflect` to allow upcasting to a `dyn Reflect`: ```rust trait MyTrait: Reflect { // ... } fn foo(value: &dyn MyTrait) { let reflected = value.as_reflect(); // ... } ``` ## Alternatives We could defer this type of logic to the crate/user. They can add these methods to their trait in the same exact way we do here. The main benefit of doing it ourselves is it makes things convenient for them (especially when using the derive macro). We could also create an `AsReflect` trait with a blanket impl over all reflected types, however, I could not get that to work for trait objects since they aren't sized. --- ## Changelog - Added trait method `Reflect::as_reflect(&self)` - Added trait method `Reflect::as_reflect_mut(&mut self)` ## Migration Guide - Manual implementors of `Reflect` will need to add implementations for the methods above (this should be pretty easy as most cases just need to return `self`)
2022-04-25 13:54:48 +00:00
#[test]
fn as_reflect() {
trait TestTrait: Reflect {}
#[derive(Reflect)]
struct TestStruct;
impl TestTrait for TestStruct {}
let trait_object: Box<dyn TestTrait> = Box::new(TestStruct);
// Should compile:
let _ = trait_object.as_reflect();
}
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
#[test]
fn should_reflect_debug() {
#[derive(Reflect)]
struct Test {
value: usize,
list: Vec<String>,
array: [f32; 3],
map: HashMap<i32, f32>,
a_struct: SomeStruct,
a_tuple_struct: SomeTupleStruct,
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
enum_unit: SomeEnum,
enum_tuple: SomeEnum,
enum_struct: SomeEnum,
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
custom: CustomDebug,
#[reflect(ignore)]
#[allow(dead_code)]
ignored: isize,
}
#[derive(Reflect)]
struct SomeStruct {
foo: String,
}
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
#[derive(Reflect)]
enum SomeEnum {
A,
B(usize),
C { value: i32 },
}
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
#[derive(Reflect)]
struct SomeTupleStruct(String);
#[derive(Reflect)]
#[reflect(Debug)]
struct CustomDebug;
impl Debug for CustomDebug {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
f.write_str("Cool debug!")
}
}
let mut map = HashMap::new();
map.insert(123, 1.23);
let test = Test {
value: 123,
list: vec![String::from("A"), String::from("B"), String::from("C")],
array: [1.0, 2.0, 3.0],
map,
a_struct: SomeStruct {
foo: String::from("A Struct!"),
},
a_tuple_struct: SomeTupleStruct(String::from("A Tuple Struct!")),
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
enum_unit: SomeEnum::A,
enum_tuple: SomeEnum::B(123),
enum_struct: SomeEnum::C { value: 321 },
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
custom: CustomDebug,
ignored: 321,
};
let reflected: &dyn Reflect = &test;
let expected = r#"
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
bevy_reflect::tests::Test {
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
value: 123,
list: [
"A",
"B",
"C",
],
array: [
1.0,
2.0,
3.0,
],
map: {
123: 1.23,
},
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
a_struct: bevy_reflect::tests::SomeStruct {
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
foo: "A Struct!",
},
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
a_tuple_struct: bevy_reflect::tests::SomeTupleStruct(
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
"A Tuple Struct!",
),
bevy_reflect: Reflect enums (#4761) # Objective > This is a revival of #1347. Credit for the original PR should go to @Davier. Currently, enums are treated as `ReflectRef::Value` types by `bevy_reflect`. Obviously, there needs to be better a better representation for enums using the reflection API. ## Solution Based on prior work from @Davier, an `Enum` trait has been added as well as the ability to automatically implement it via the `Reflect` derive macro. This allows enums to be expressed dynamically: ```rust #[derive(Reflect)] enum Foo { A, B(usize), C { value: f32 }, } let mut foo = Foo::B(123); assert_eq!("B", foo.variant_name()); assert_eq!(1, foo.field_len()); let new_value = DynamicEnum::from(Foo::C { value: 1.23 }); foo.apply(&new_value); assert_eq!(Foo::C{value: 1.23}, foo); ``` ### Features #### Derive Macro Use the `#[derive(Reflect)]` macro to automatically implement the `Enum` trait for enum definitions. Optionally, you can use `#[reflect(ignore)]` with both variants and variant fields, just like you can with structs. These ignored items will not be considered as part of the reflection and cannot be accessed via reflection. ```rust #[derive(Reflect)] enum TestEnum { A, // Uncomment to ignore all of `B` // #[reflect(ignore)] B(usize), C { // Uncomment to ignore only field `foo` of `C` // #[reflect(ignore)] foo: f32, bar: bool, }, } ``` #### Dynamic Enums Enums may be created/represented dynamically via the `DynamicEnum` struct. The main purpose of this struct is to allow enums to be deserialized into a partial state and to allow dynamic patching. In order to ensure conversion from a `DynamicEnum` to a concrete enum type goes smoothly, be sure to add `FromReflect` to your derive macro. ```rust let mut value = TestEnum::A; // Create from a concrete instance let dyn_enum = DynamicEnum::from(TestEnum::B(123)); value.apply(&dyn_enum); assert_eq!(TestEnum::B(123), value); // Create a purely dynamic instance let dyn_enum = DynamicEnum::new("TestEnum", "A", ()); value.apply(&dyn_enum); assert_eq!(TestEnum::A, value); ``` #### Variants An enum value is always represented as one of its variants— never the enum in its entirety. ```rust let value = TestEnum::A; assert_eq!("A", value.variant_name()); // Since we are using the `A` variant, we cannot also be the `B` variant assert_ne!("B", value.variant_name()); ``` All variant types are representable within the `Enum` trait: unit, struct, and tuple. You can get the current type like: ```rust match value.variant_type() { VariantType::Unit => println!("A unit variant!"), VariantType::Struct => println!("A struct variant!"), VariantType::Tuple => println!("A tuple variant!"), } ``` > Notice that they don't contain any values representing the fields. These are purely tags. If a variant has them, you can access the fields as well: ```rust let mut value = TestEnum::C { foo: 1.23, bar: false }; // Read/write specific fields *value.field_mut("bar").unwrap() = true; // Iterate over the entire collection of fields for field in value.iter_fields() { println!("{} = {:?}", field.name(), field.value()); } ``` #### Variant Swapping It might seem odd to group all variant types under a single trait (why allow `iter_fields` on a unit variant?), but the reason this was done ~~is to easily allow *variant swapping*.~~ As I was recently drafting up the **Design Decisions** section, I discovered that other solutions could have been made to work with variant swapping. So while there are reasons to keep the all-in-one approach, variant swapping is _not_ one of them. ```rust let mut value: Box<dyn Enum> = Box::new(TestEnum::A); value.set(Box::new(TestEnum::B(123))).unwrap(); ``` #### Serialization Enums can be serialized and deserialized via reflection without needing to implement `Serialize` or `Deserialize` themselves (which can save thousands of lines of generated code). Below are the ways an enum can be serialized. > Note, like the rest of reflection-based serialization, the order of the keys in these representations is important! ##### Unit ```json { "type": "my_crate::TestEnum", "enum": { "variant": "A" } } ``` ##### Tuple ```json { "type": "my_crate::TestEnum", "enum": { "variant": "B", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` <details> <summary>Effects on Option</summary> This ends up making `Option` look a little ugly: ```json { "type": "core::option::Option<usize>", "enum": { "variant": "Some", "tuple": [ { "type": "usize", "value": 123 } ] } } ``` </details> ##### Struct ```json { "type": "my_crate::TestEnum", "enum": { "variant": "C", "struct": { "foo": { "type": "f32", "value": 1.23 }, "bar": { "type": "bool", "value": false } } } } ``` ## Design Decisions <details> <summary><strong>View Section</strong></summary> This section is here to provide some context for why certain decisions were made for this PR, alternatives that could have been used instead, and what could be improved upon in the future. ### Variant Representation One of the biggest decisions was to decide on how to represent variants. The current design uses a "all-in-one" design where unit, tuple, and struct variants are all simultaneously represented by the `Enum` trait. This is not the only way it could have been done, though. #### Alternatives ##### 1. Variant Traits One way of representing variants would be to define traits for each variant, implementing them whenever an enum featured at least one instance of them. This would allow us to define variants like: ```rust pub trait Enum: Reflect { fn variant(&self) -> Variant; } pub enum Variant<'a> { Unit, Tuple(&'a dyn TupleVariant), Struct(&'a dyn StructVariant), } pub trait TupleVariant { fn field_len(&self) -> usize; // ... } ``` And then do things like: ```rust fn get_tuple_len(foo: &dyn Enum) -> usize { match foo.variant() { Variant::Tuple(tuple) => tuple.field_len(), _ => panic!("not a tuple variant!") } } ``` The reason this PR does not go with this approach is because of the fact that variants are not separate types. In other words, we cannot implement traits on specific variants— these cover the *entire* enum. This means we offer an easy footgun: ```rust let foo: Option<i32> = None; let my_enum = Box::new(foo) as Box<dyn TupleVariant>; ``` Here, `my_enum` contains `foo`, which is a unit variant. However, since we need to implement `TupleVariant` for `Option` as a whole, it's possible to perform such a cast. This is obviously wrong, but could easily go unnoticed. So unfortunately, this makes it not a good candidate for representing variants. ##### 2. Variant Structs To get around the issue of traits necessarily needing to apply to both the enum and its variants, we could instead use structs that are created on a per-variant basis. This was also considered but was ultimately [[removed](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c)](https://github.com/bevyengine/bevy/pull/4761/commits/71d27ab3c6871bb188d8b46512db3b0922a56a0c) due to concerns about allocations. Each variant struct would probably look something like: ```rust pub trait Enum: Reflect { fn variant_mut(&self) -> VariantMut; } pub enum VariantMut<'a> { Unit, Tuple(TupleVariantMut), Struct(StructVariantMut), } struct StructVariantMut<'a> { fields: Vec<&'a mut dyn Reflect>, field_indices: HashMap<Cow<'static, str>, usize> } ``` This allows us to isolate struct variants into their own defined struct and define methods specifically for their use. It also prevents users from casting to it since it's not a trait. However, this is not an optimal solution. Both `field_indices` and `fields` will require an allocation (remember, a `Box<[T]>` still requires a `Vec<T>` in order to be constructed). This *might* be a problem if called frequently enough. ##### 3. Generated Structs The original design, implemented by @Davier, instead generates structs specific for each variant. So if we had a variant path like `Foo::Bar`, we'd generate a struct named `FooBarWrapper`. This would be newtyped around the original enum and forward tuple or struct methods to the enum with the chosen variant. Because it involved using the `Tuple` and `Struct` traits (which are also both bound on `Reflect`), this meant a bit more code had to be generated. For a single struct variant with one field, the generated code amounted to ~110LoC. However, each new field added to that variant only added ~6 more LoC. In order to work properly, the enum had to be transmuted to the generated struct: ```rust fn variant(&self) -> crate::EnumVariant<'_> { match self { Foo::Bar {value: i32} => { let wrapper_ref = unsafe { std::mem::transmute::<&Self, &FooBarWrapper>(self) }; crate::EnumVariant::Struct(wrapper_ref as &dyn crate::Struct) } } } ``` This works because `FooBarWrapper` is defined as `repr(transparent)`. Out of all the alternatives, this would probably be the one most likely to be used again in the future. The reasons for why this PR did not continue to use it was because: * To reduce generated code (which would hopefully speed up compile times) * To avoid cluttering the code with generated structs not visible to the user * To keep bevy_reflect simple and extensible (these generated structs act as proxies and might not play well with current or future systems) * To avoid additional unsafe blocks * My own misunderstanding of @Davier's code That last point is obviously on me. I misjudged the code to be too unsafe and unable to handle variant swapping (which it probably could) when I was rebasing it. Looking over it again when writing up this whole section, I see that it was actually a pretty clever way of handling variant representation. #### Benefits of All-in-One As stated before, the current implementation uses an all-in-one approach. All variants are capable of containing fields as far as `Enum` is concerned. This provides a few benefits that the alternatives do not (reduced indirection, safer code, etc.). The biggest benefit, though, is direct field access. Rather than forcing users to have to go through pattern matching, we grant direct access to the fields contained by the current variant. The reason we can do this is because all of the pattern matching happens internally. Getting the field at index `2` will automatically return `Some(...)` for the current variant if it has a field at that index or `None` if it doesn't (or can't). This could be useful for scenarios where the variant has already been verified or just set/swapped (or even where the type of variant doesn't matter): ```rust let dyn_enum: &mut dyn Enum = &mut Foo::Bar {value: 123}; // We know it's the `Bar` variant let field = dyn_enum.field("value").unwrap(); ``` Reflection is not a type-safe abstraction— almost every return value is wrapped in `Option<...>`. There are plenty of places to check and recheck that a value is what Reflect says it is. Forcing users to have to go through `match` each time they want to access a field might just be an extra step among dozens of other verification processes. Some might disagree, but ultimately, my view is that the benefit here is an improvement to the ergonomics and usability of reflected enums. </details> --- ## Changelog ### Added * Added `Enum` trait * Added `Enum` impl to `Reflect` derive macro * Added `DynamicEnum` struct * Added `DynamicVariant` * Added `EnumInfo` * Added `VariantInfo` * Added `StructVariantInfo` * Added `TupleVariantInfo` * Added `UnitVariantInfo` * Added serializtion/deserialization support for enums * Added `EnumSerializer` * Added `VariantType` * Added `VariantFieldIter` * Added `VariantField` * Added `enum_partial_eq(...)` * Added `enum_hash(...)` ### Changed * `Option<T>` now implements `Enum` * `bevy_window` now depends on `bevy_reflect` * Implemented `Reflect` and `FromReflect` for `WindowId` * Derive `FromReflect` on `PerspectiveProjection` * Derive `FromReflect` on `OrthographicProjection` * Derive `FromReflect` on `WindowOrigin` * Derive `FromReflect` on `ScalingMode` * Derive `FromReflect` on `DepthCalculation` ## Migration Guide * Enums no longer need to be treated as values and usages of `#[reflect_value(...)]` can be removed or replaced by `#[reflect(...)]` * Enums (including `Option<T>`) now take a different format when serializing. The format is described above, but this may cause issues for existing scenes that make use of enums. --- Also shout out to @nicopap for helping clean up some of the code here! It's a big feature so help like this is really appreciated! Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2022-08-02 22:14:41 +00:00
enum_unit: A,
enum_tuple: B(
123,
),
enum_struct: C {
value: 321,
},
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
custom: Cool debug!,
}"#;
assert_eq!(expected, format!("\n{reflected:#?}"));
bevy_reflect: Improve debug formatting for reflected types (#4218) # Objective Debugging reflected types can be somewhat frustrating since all `dyn Reflect` trait objects return something like `Reflect(core::option::Option<alloc::string::String>)`. It would be much nicer to be able to see the actual value— or even use a custom `Debug` implementation. ## Solution Added `Reflect::debug` which allows users to customize the debug output. It sets defaults for all `ReflectRef` subtraits and falls back to `Reflect(type_name)` if no `Debug` implementation was registered. To register a custom `Debug` impl, users can add `#[reflect(Debug)]` like they can with other traits. ### Example Using the following structs: ```rust #[derive(Reflect)] pub struct Foo { a: usize, nested: Bar, #[reflect(ignore)] _ignored: NonReflectedValue, } #[derive(Reflect)] pub struct Bar { value: Vec2, tuple_value: (i32, String), list_value: Vec<usize>, // We can't determine debug formatting for Option<T> yet unknown_value: Option<String>, custom_debug: CustomDebug } #[derive(Reflect)] #[reflect(Debug)] struct CustomDebug; impl Debug for CustomDebug { fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { write!(f, "This is a custom debug!") } } pub struct NonReflectedValue { _a: usize, } ``` We can do: ```rust let value = Foo { a: 1, _ignored: NonReflectedValue { _a: 10 }, nested: Bar { value: Vec2::new(1.23, 3.21), tuple_value: (123, String::from("Hello")), list_value: vec![1, 2, 3], unknown_value: Some(String::from("World")), custom_debug: CustomDebug }, }; let reflected_value: &dyn Reflect = &value; println!("{:#?}", reflected_value) ``` Which results in: ```rust Foo { a: 2, nested: Bar { value: Vec2( 1.23, 3.21, ), tuple_value: ( 123, "Hello", ), list_value: [ 1, 2, 3, ], unknown_value: Reflect(core::option::Option<alloc::string::String>), custom_debug: This is a custom debug!, }, } ``` Notice that neither `Foo` nor `Bar` implement `Debug`, yet we can still deduce it. This might be a concern if we're worried about leaking internal values. If it is, we might want to consider a way to exclude fields (possibly with a `#[reflect(hide)]` macro) or make it purely opt in (as opposed to the default implementation automatically handled by ReflectRef subtraits). Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
2022-05-30 16:41:31 +00:00
}
Support multiple `#[reflect]`/`#[reflect_value]` + improve error messages (#6237) # Objective Currently, surprising behavior happens when specifying `#[reflect(...)]` or `#[reflect_value(...)]` multiple times. Rather than merging the traits lists from all attributes, only the trait list from the last attribute is used. For example, in the following code, only the `Debug` and `Hash` traits are reflected and not `Default` or `PartialEq`: ```rs #[derive(Debug, PartialEq, Hash, Default, Reflect)] #[reflect(PartialEq, Default)] #[reflect(Debug, Hash)] struct Foo; ``` This is especially important when some traits should only be reflected under certain circumstances. For example, this previously had surprisingly behavior when the "serialize" feature is enabled: ```rs #[derive(Debug, Hash, Reflect)] #[reflect(Debug, Hash)] #[cfg_attr( feature = "serialize", derive(Serialize, Deserialize), reflect(Serialize, Deserialize) ] struct Foo; ``` In addition, compile error messages generated from using the derive macro often point to the `#[derive(Reflect)]` rather than to the source of the error. It would be a lot more helpful if the compiler errors pointed to what specifically caused the error rather than just to the derive macro itself. ## Solution Merge the trait lists in all `#[reflect(...)]` and `#[reflect_value(...)]` attributes. Additionally, make `#[reflect]` and `#[reflect_value]` mutually exclusive. Additionally, span information is carried throughout some parts of the code now to ensure that error messages point to more useful places and better indicate what caused those errors. For example, `#[reflect(Hash, Hash)]` points to the second `Hash` as the source of an error. Also, in the following example, the compiler error now points to the `Hash` in `#[reflect(Hash)]` rather than to the derive macro: ```rs #[derive(Reflect)] #[reflect(Hash)] // <-- compiler error points to `Hash` for lack of a `Hash` implementation struct Foo; ``` --- ## Changelog Changed - Using multiple `#[reflect(...)]` or `#[reflect_value(...)]` attributes now merges the trait lists. For example, `#[reflect(Debug, Hash)] #[reflect(PartialEq, Default)]` is equivalent to `#[reflect(Debug, Hash, PartialEq, Default)]`. - Multiple `#[reflect(...)]` and `#[reflect_value(...)]` attributes were previously accepted, but only the last attribute was respected. - Using both `#[reflect(...)]` and `#[reflect_value(...)]` was previously accepted, but had surprising behavior. This is no longer accepted. - Improved error messages for `#[derive(Reflect)]` by propagating useful span information. Many errors should now point to the source of those errors rather than to the derive macro.
2022-10-17 14:38:56 +00:00
#[test]
fn multiple_reflect_lists() {
#[derive(Hash, PartialEq, Reflect)]
#[reflect(Debug, Hash)]
#[reflect(PartialEq)]
struct Foo(i32);
impl Debug for Foo {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "Foo")
}
}
let foo = Foo(123);
let foo: &dyn Reflect = &foo;
assert!(foo.reflect_hash().is_some());
assert_eq!(Some(true), foo.reflect_partial_eq(foo));
assert_eq!("Foo".to_string(), format!("{foo:?}"));
}
#[test]
fn multiple_reflect_value_lists() {
#[derive(Clone, Hash, PartialEq, Reflect)]
#[reflect_value(Debug, Hash)]
#[reflect_value(PartialEq)]
struct Foo(i32);
impl Debug for Foo {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "Foo")
}
}
let foo = Foo(123);
let foo: &dyn Reflect = &foo;
assert!(foo.reflect_hash().is_some());
assert_eq!(Some(true), foo.reflect_partial_eq(foo));
assert_eq!("Foo".to_string(), format!("{foo:?}"));
}
#[test]
fn custom_debug_function() {
#[derive(Reflect)]
#[reflect(Debug(custom_debug))]
struct Foo {
a: u32,
}
fn custom_debug(_x: &Foo, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "123")
}
let foo = Foo { a: 1 };
let foo: &dyn Reflect = &foo;
assert_eq!("123", format!("{:?}", foo));
}
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
#[test]
fn should_allow_custom_where() {
#[derive(Reflect)]
#[reflect(where T: Default)]
struct Foo<T>(String, #[reflect(ignore)] PhantomData<T>);
#[derive(Default, TypePath)]
struct Bar;
#[derive(TypePath)]
struct Baz;
assert_impl_all!(Foo<Bar>: Reflect);
assert_not_impl_all!(Foo<Baz>: Reflect);
}
#[test]
fn should_allow_empty_custom_where() {
#[derive(Reflect)]
#[reflect(where)]
struct Foo<T>(String, #[reflect(ignore)] PhantomData<T>);
#[derive(TypePath)]
struct Bar;
assert_impl_all!(Foo<Bar>: Reflect);
}
#[test]
fn should_allow_multiple_custom_where() {
#[derive(Reflect)]
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
#[reflect(where T: Default)]
#[reflect(where U: std::ops::Add<T>)]
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
struct Foo<T, U>(T, U);
#[derive(Reflect)]
struct Baz {
a: Foo<i32, i32>,
b: Foo<u32, u32>,
}
assert_impl_all!(Foo<i32, i32>: Reflect);
assert_not_impl_all!(Foo<i32, usize>: Reflect);
}
#[test]
fn should_allow_custom_where_with_assoc_type() {
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
trait Trait {
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
type Assoc;
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
}
// We don't need `T` to be `Reflect` since we only care about `T::Assoc`
#[derive(Reflect)]
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
#[reflect(where T::Assoc: core::fmt::Display)]
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
struct Foo<T: Trait>(T::Assoc);
#[derive(TypePath)]
struct Bar;
impl Trait for Bar {
type Assoc = usize;
}
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
#[derive(TypePath)]
struct Baz;
impl Trait for Baz {
type Assoc = (f32, f32);
}
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
assert_impl_all!(Foo<Bar>: Reflect);
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
assert_not_impl_all!(Foo<Baz>: Reflect);
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
}
#[test]
fn recursive_typed_storage_does_not_hang() {
#[derive(Reflect)]
struct Recurse<T>(T);
let _ = <Recurse<Recurse<()>> as Typed>::type_info();
let _ = <Recurse<Recurse<()>> as TypePath>::type_path();
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
#[derive(Reflect)]
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
#[reflect(no_field_bounds)]
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
struct SelfRecurse {
recurse: Vec<SelfRecurse>,
}
let _ = <SelfRecurse as Typed>::type_info();
let _ = <SelfRecurse as TypePath>::type_path();
#[derive(Reflect)]
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
#[reflect(no_field_bounds)]
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
enum RecurseA {
Recurse(RecurseB),
}
#[derive(Reflect)]
bevy_reflect: Split `#[reflect(where)]` (#11597) # Objective Revert the changes to type parameter bounds introduced in #9046, improves the `#[reflect(where)]` attribute (also from #9046), and adds the ability to opt out of field bounds. This is based on suggestions by @soqb and discussion on [Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427). ## Solution Reverts the changes to type parameter bounds when deriving `Reflect`, introduced in #9046. This was originally done as a means of fixing a recursion issue (#8965). However, as @soqb pointed out, we could achieve the same result by simply making an opt-out attribute instead of messing with the type parameter bounds. This PR has four main changes: 1. Reverts the type parameter bounds from #9046 2. Includes `TypePath` as a default bound for active fields 3. Changes `#reflect(where)]` to be strictly additive 4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds Change 1 means that, like before, type parameters only receive at most the `TypePath` bound (if `#[reflect(type_path = false)]` is not present) and active fields receive the `Reflect` or `FromReflect` bound. And with Change 2, they will also receive `TypePath` (since it's indirectly required by `Typed` to construct `NamedField` and `UnnamedField` instances). Change 3 was made to make room for Change 4. By splitting out the responsibility of `#reflect(where)]`, we can use it with or without `#reflect(no_field_bounds)]` for various use cases. For example, if we hadn't done this, the following would have failed: ```rust // Since we're not using `#reflect(no_field_bounds)]`, // `T::Assoc` is automatically given the required bounds // of `FromReflect + TypePath` #[derive(Reflect)] #[reflect(where T::Assoc: OtherTrait)] struct Foo<T: MyTrait> { value: T::Assoc, } ``` This provides more flexibility to the user while still letting them add or remove most trait bounds. And to solve the original recursion issue, we can do: ```rust #[derive(Reflect)] #[reflect(no_field_bounds)] // <-- Added struct Foo { foo: Vec<Foo> } ``` #### Bounds All in all, we now have four sets of trait bounds: - `Self` gets the bounds `Any + Send + Sync` - Type parameters get the bound `TypePath`. This can be opted out of with `#[reflect(type_path = false)]` - Active fields get the bounds `TypePath` and `FromReflect`/`Reflect` bounds. This can be opted out of with `#reflect(no_field_bounds)]` - Custom bounds can be added with `#[reflect(where)]` --- ## Changelog - Revert some changes #9046 - `#reflect(where)]` is now strictly additive - Added `#reflect(no_field_bounds)]` attribute to opt out of automatic field trait bounds when deriving `Reflect` - Made the `TypePath` requirement on fields when deriving `Reflect` more explicit ## Migration Guide > [!important] > This PR shouldn't be a breaking change relative to the current version of Bevy (v0.12). And since it removes the breaking parts of #9046, that PR also won't need a migration guide.
2024-01-29 17:54:17 +00:00
// `#[reflect(no_field_bounds)]` not needed since already added to `RecurseA`
bevy_reflect: Type parameter bounds (#9046) # Objective Fixes #8965. #### Background For convenience and to ensure everything is setup properly, we automatically add certain bounds to the derived types. The current implementation does this by taking the types from all active fields and adding them to the where-clause of the generated impls. I believe this method was chosen because it won't add bounds to types that are otherwise ignored. ```rust #[derive(Reflect)] struct Foo<T, U: SomeTrait, V> { t: T, u: U::Assoc, #[reflect(ignore)] v: [V; 2] } // Generates something like: impl<T, U: SomeTrait, V> for Foo<T, U, V> where // Active: T: Reflect, U::Assoc: Reflect, // Ignored: [V; 2]: Send + Sync + Any { // ... } ``` The self-referential type fails because it ends up using _itself_ as a type bound due to being one of its own active fields. ```rust #[derive(Reflect)] struct Foo { foo: Vec<Foo> } // Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ... ``` ## Solution We can't simply parse all field types for the name of our type. That would be both complex and prone to errors and false-positives. And even if it wasn't, what would we replace the bound with? Instead, I opted to go for a solution that only adds the bounds to what really needs it: the type parameters. While the bounds on concrete types make errors a bit cleaner, they aren't strictly necessary. This means we can change our generated where-clause to only add bounds to generic type parameters. Doing this, though, returns us back to the problem of over-bounding parameters that don't need to be bounded. To solve this, I added a new container attribute (based on [this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925) comment and @nicopap's [comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780)) that allows us to pass in a custom where clause to modify what bounds are added to these type parameters. This allows us to do stuff like: ```rust trait Trait { type Assoc; } // We don't need `T` to be reflectable since we only care about `T::Assoc`. #[derive(Reflect)] #[reflect(where T::Assoc: FromReflect)] struct Foo<T: Trait>(T::Assoc); #[derive(TypePath)] struct Bar; impl Trait for Bar { type Assoc = usize; } #[derive(Reflect)] struct Baz { a: Foo<Bar>, } ``` > **Note** > I also [tried](https://github.com/bevyengine/bevy/commit/dc139ea34c4737da3ea7ab7ea2e8701462693d02) allowing `#[reflect(ignore)]` to be used on the type parameters themselves, but that proved problematic since the derive macro does not consume the attribute. This is why I went with the container attribute approach. ### Alternatives One alternative could possibly be to just not add reflection bounds automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`, and `TypePath`). The downside here is we add more friction to using reflection, which already comes with its own set of considerations. This is a potentially viable option, but we really need to consider whether or not the ergonomics hit is worth it. If we did decide to go the more manual route, we should at least consider something like #5772 to make it easier for users to add the right bounds (although, this could still become tricky with `FromReflect` also being automatically derived). ### Open Questions 1. Should we go with this approach or the manual alternative? 2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static` trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~ Scratch that, went with a normal where clause 3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using a normal where clause ### TODO - [x] Add compile-fail tests --- ## Changelog - Fixed issue preventing recursive types from deriving `Reflect` - Changed how where-clause bounds are generated by the `Reflect` derive macro - They are now only applied to the type parameters, not to all active fields - Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container attribute ## Migration Guide When deriving `Reflect`, generic type params that do not need the automatic reflection bounds (such as `Reflect`) applied to them will need to opt-out using a custom where clause like: `#[reflect(where T: Trait, U::Assoc: Trait, ...)]`. The attribute can define custom bounds only used by the reflection impls. To simply opt-out all the type params, we can pass in an empty where clause: `#[reflect(where)]`. ```rust // BEFORE: #[derive(Reflect)] struct Foo<T>(#[reflect(ignore)] T); // AFTER: #[derive(Reflect)] #[reflect(where)] struct Foo<T>(#[reflect(ignore)] T); ``` --------- Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
2024-01-28 16:24:03 +00:00
struct RecurseB {
vector: Vec<RecurseA>,
}
let _ = <RecurseA as Typed>::type_info();
let _ = <RecurseA as TypePath>::type_path();
let _ = <RecurseB as Typed>::type_info();
let _ = <RecurseB as TypePath>::type_path();
}
bevy_reflect: Recursive registration (#5781) # Objective Resolves #4154 Currently, registration must all be done manually: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app .register_type::<Foo>() .register_type::<Bar>() .register_type::<Baz>() // .register_type::<usize>() <- This one is handled by Bevy, thankfully // ... } ``` This can grow really quickly and become very annoying to add, remove, and update as types change. It would be great if we could help reduce the number of types that a user must manually implement themselves. ## Solution As suggested in #4154, this PR adds automatic recursive registration. Essentially, when a type is registered, it may now also choose to register additional types along with it using the new `GetTypeRegistration::register_type_dependencies` trait method. The `Reflect` derive macro now automatically does this for all fields in structs, tuple structs, struct variants, and tuple variants. This is also done for tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>`. This allows us to simplify the code above like: ```rust #[derive(Reflect)] struct Foo(Bar); #[derive(Reflect)] struct Bar(Baz); #[derive(Reflect)] struct Baz(usize); fn main() { // ... app.register_type::<Foo>() // ... } ``` This automatic registration only occurs if the type has not yet been registered. If it has been registered, we simply skip it and move to the next one. This reduces the cost of registration and prevents overwriting customized registrations. ## Considerations While this does improve ergonomics on one front, it's important to look at some of the arguments against adopting a PR like this. #### Generic Bounds ~~Since we need to be able to register the fields individually, we need those fields to implement `GetTypeRegistration`. This forces users to then add this trait as a bound on their generic arguments. This annoyance could be relieved with something like #5772.~~ This is no longer a major issue as the `Reflect` derive now adds the `GetTypeRegistration` bound by default. This should technically be okay, since we already add the `Reflect` bound. However, this can also be considered a breaking change for manual implementations that left out a `GetTypeRegistration` impl ~~or for items that contain dynamic types (e.g. `DynamicStruct`) since those also do not implement `GetTypeRegistration`~~. #### Registration Assumptions By automatically registering fields, users might inadvertently be relying on certain types to be automatically registered. If `Foo` auto-registers `Bar`, but `Foo` is later removed from the code, then anywhere that previously used or relied on `Bar`'s registration would now fail. --- ## Changelog - Added recursive type registration to structs, tuple structs, struct variants, tuple variants, tuples, arrays, `Vec<T>`, `HashMap<K, V>`, and `Option<T>` - Added a new trait in the hidden `bevy_reflect::__macro_exports` module called `RegisterForReflection` - Added `GetTypeRegistration` impl for `bevy_render::render_asset::RenderAssetUsages` ## Migration Guide All types that derive `Reflect` will now automatically add `GetTypeRegistration` as a bound on all (unignored) fields. This means that all reflected fields will need to also implement `GetTypeRegistration`. If all fields **derive** `Reflect` or are implemented in `bevy_reflect`, this should not cause any issues. However, manual implementations of `Reflect` that excluded a `GetTypeRegistration` impl for their type will need to add one. ```rust #[derive(Reflect)] struct Foo<T: FromReflect> { data: MyCustomType<T> } // OLD impl<T: FromReflect> Reflect for MyCustomType<T> {/* ... */} // NEW impl<T: FromReflect + GetTypeRegistration> Reflect for MyCustomType<T> {/* ... */} impl<T: FromReflect + GetTypeRegistration> GetTypeRegistration for MyCustomType<T> {/* ... */} ``` --------- Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: radiish <cb.setho@gmail.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2024-03-04 19:04:10 +00:00
#[test]
fn recursive_registration_does_not_hang() {
#[derive(Reflect)]
struct Recurse<T>(T);
let mut registry = TypeRegistry::empty();
registry.register::<Recurse<Recurse<()>>>();
#[derive(Reflect)]
#[reflect(no_field_bounds)]
struct SelfRecurse {
recurse: Vec<SelfRecurse>,
}
registry.register::<SelfRecurse>();
#[derive(Reflect)]
#[reflect(no_field_bounds)]
enum RecurseA {
Recurse(RecurseB),
}
#[derive(Reflect)]
struct RecurseB {
vector: Vec<RecurseA>,
}
registry.register::<RecurseA>();
assert!(registry.contains(TypeId::of::<RecurseA>()));
assert!(registry.contains(TypeId::of::<RecurseB>()));
}
bevy_reflect: Opt-out attribute for `TypePath` (#9140) # Objective Fixes #9094 ## Solution Takes a bit from [this](https://github.com/bevyengine/bevy/issues/9094#issuecomment-1629333851) comment as well as a [comment](https://discord.com/channels/691052431525675048/1002362493634629796/1128024873260810271) from @soqb. This allows users to opt-out of the `TypePath` implementation that is automatically generated by the `Reflect` derive macro, allowing custom `TypePath` implementations. ```rust #[derive(Reflect)] #[reflect(type_path = false)] struct Foo<T> { #[reflect(ignore)] _marker: PhantomData<T>, } struct NotTypePath; impl<T: 'static> TypePath for Foo<T> { fn type_path() -> &'static str { std::any::type_name::<Self>() } fn short_type_path() -> &'static str { static CELL: GenericTypePathCell = GenericTypePathCell::new(); CELL.get_or_insert::<Self, _>(|| { bevy_utils::get_short_name(std::any::type_name::<Self>()) }) } fn crate_name() -> Option<&'static str> { Some("my_crate") } fn module_path() -> Option<&'static str> { Some("my_crate::foo") } fn type_ident() -> Option<&'static str> { Some("Foo") } } // Can use `TypePath` let _ = <Foo<NotTypePath> as TypePath>::type_path(); // Can register the type let mut registry = TypeRegistry::default(); registry.register::<Foo<NotTypePath>>(); ``` #### Type Path Stability The stability of type paths mainly come into play during serialization. If a type is moved between builds, an unstable type path may become invalid. Users that opt-out of `TypePath` and rely on something like `std::any::type_name` as in the example above, should be aware that this solution removes the stability guarantees. Deserialization thus expects that type to never move. If it does, then the serialized type paths will need to be updated accordingly. If a user depends on stability, they will need to implement that stability logic manually (probably by looking at the expanded output of a typical `Reflect`/`TypePath` derive). This could be difficult for type parameters that don't/can't implement `TypePath`, and will need to make heavy use of string parsing and manipulation to achieve the same effect (alternatively, they can choose to simply exclude any type parameter that doesn't implement `TypePath`). --- ## Changelog - Added the `#[reflect(type_path = false)]` attribute to opt out of the `TypePath` impl when deriving `Reflect` --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-08-10 00:37:56 +00:00
#[test]
fn can_opt_out_type_path() {
#[derive(Reflect)]
#[reflect(type_path = false)]
struct Foo<T> {
#[reflect(ignore)]
_marker: PhantomData<T>,
}
struct NotTypePath;
impl<T: 'static> TypePath for Foo<T> {
fn type_path() -> &'static str {
std::any::type_name::<Self>()
}
fn short_type_path() -> &'static str {
static CELL: GenericTypePathCell = GenericTypePathCell::new();
CELL.get_or_insert::<Self, _>(|| {
bevy_utils::get_short_name(std::any::type_name::<Self>())
})
}
fn type_ident() -> Option<&'static str> {
Some("Foo")
}
bevy_reflect: Opt-out attribute for `TypePath` (#9140) # Objective Fixes #9094 ## Solution Takes a bit from [this](https://github.com/bevyengine/bevy/issues/9094#issuecomment-1629333851) comment as well as a [comment](https://discord.com/channels/691052431525675048/1002362493634629796/1128024873260810271) from @soqb. This allows users to opt-out of the `TypePath` implementation that is automatically generated by the `Reflect` derive macro, allowing custom `TypePath` implementations. ```rust #[derive(Reflect)] #[reflect(type_path = false)] struct Foo<T> { #[reflect(ignore)] _marker: PhantomData<T>, } struct NotTypePath; impl<T: 'static> TypePath for Foo<T> { fn type_path() -> &'static str { std::any::type_name::<Self>() } fn short_type_path() -> &'static str { static CELL: GenericTypePathCell = GenericTypePathCell::new(); CELL.get_or_insert::<Self, _>(|| { bevy_utils::get_short_name(std::any::type_name::<Self>()) }) } fn crate_name() -> Option<&'static str> { Some("my_crate") } fn module_path() -> Option<&'static str> { Some("my_crate::foo") } fn type_ident() -> Option<&'static str> { Some("Foo") } } // Can use `TypePath` let _ = <Foo<NotTypePath> as TypePath>::type_path(); // Can register the type let mut registry = TypeRegistry::default(); registry.register::<Foo<NotTypePath>>(); ``` #### Type Path Stability The stability of type paths mainly come into play during serialization. If a type is moved between builds, an unstable type path may become invalid. Users that opt-out of `TypePath` and rely on something like `std::any::type_name` as in the example above, should be aware that this solution removes the stability guarantees. Deserialization thus expects that type to never move. If it does, then the serialized type paths will need to be updated accordingly. If a user depends on stability, they will need to implement that stability logic manually (probably by looking at the expanded output of a typical `Reflect`/`TypePath` derive). This could be difficult for type parameters that don't/can't implement `TypePath`, and will need to make heavy use of string parsing and manipulation to achieve the same effect (alternatively, they can choose to simply exclude any type parameter that doesn't implement `TypePath`). --- ## Changelog - Added the `#[reflect(type_path = false)]` attribute to opt out of the `TypePath` impl when deriving `Reflect` --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-08-10 00:37:56 +00:00
fn crate_name() -> Option<&'static str> {
Some("bevy_reflect")
}
fn module_path() -> Option<&'static str> {
Some("bevy_reflect::tests")
}
}
// Can use `TypePath`
let path = <Foo<NotTypePath> as TypePath>::type_path();
assert_eq!("bevy_reflect::tests::can_opt_out_type_path::Foo<bevy_reflect::tests::can_opt_out_type_path::NotTypePath>", path);
// Can register the type
let mut registry = TypeRegistry::default();
registry.register::<Foo<NotTypePath>>();
let registration = registry.get(TypeId::of::<Foo<NotTypePath>>()).unwrap();
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
assert_eq!(
"Foo<NotTypePath>",
registration.type_info().type_path_table().short_path()
);
bevy_reflect: Opt-out attribute for `TypePath` (#9140) # Objective Fixes #9094 ## Solution Takes a bit from [this](https://github.com/bevyengine/bevy/issues/9094#issuecomment-1629333851) comment as well as a [comment](https://discord.com/channels/691052431525675048/1002362493634629796/1128024873260810271) from @soqb. This allows users to opt-out of the `TypePath` implementation that is automatically generated by the `Reflect` derive macro, allowing custom `TypePath` implementations. ```rust #[derive(Reflect)] #[reflect(type_path = false)] struct Foo<T> { #[reflect(ignore)] _marker: PhantomData<T>, } struct NotTypePath; impl<T: 'static> TypePath for Foo<T> { fn type_path() -> &'static str { std::any::type_name::<Self>() } fn short_type_path() -> &'static str { static CELL: GenericTypePathCell = GenericTypePathCell::new(); CELL.get_or_insert::<Self, _>(|| { bevy_utils::get_short_name(std::any::type_name::<Self>()) }) } fn crate_name() -> Option<&'static str> { Some("my_crate") } fn module_path() -> Option<&'static str> { Some("my_crate::foo") } fn type_ident() -> Option<&'static str> { Some("Foo") } } // Can use `TypePath` let _ = <Foo<NotTypePath> as TypePath>::type_path(); // Can register the type let mut registry = TypeRegistry::default(); registry.register::<Foo<NotTypePath>>(); ``` #### Type Path Stability The stability of type paths mainly come into play during serialization. If a type is moved between builds, an unstable type path may become invalid. Users that opt-out of `TypePath` and rely on something like `std::any::type_name` as in the example above, should be aware that this solution removes the stability guarantees. Deserialization thus expects that type to never move. If it does, then the serialized type paths will need to be updated accordingly. If a user depends on stability, they will need to implement that stability logic manually (probably by looking at the expanded output of a typical `Reflect`/`TypePath` derive). This could be difficult for type parameters that don't/can't implement `TypePath`, and will need to make heavy use of string parsing and manipulation to achieve the same effect (alternatively, they can choose to simply exclude any type parameter that doesn't implement `TypePath`). --- ## Changelog - Added the `#[reflect(type_path = false)]` attribute to opt out of the `TypePath` impl when deriving `Reflect` --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-08-10 00:37:56 +00:00
}
#[test]
fn dynamic_types_debug_format() {
#[derive(Debug, Reflect)]
struct TestTupleStruct(u32);
#[derive(Debug, Reflect)]
enum TestEnum {
A(u32),
B,
}
#[derive(Debug, Reflect)]
// test DynamicStruct
struct TestStruct {
// test DynamicTuple
tuple: (u32, u32),
// test DynamicTupleStruct
tuple_struct: TestTupleStruct,
// test DynamicList
list: Vec<u32>,
// test DynamicArray
array: [u32; 3],
// test DynamicEnum
e: TestEnum,
// test DynamicMap
map: HashMap<u32, u32>,
// test reflected value
value: u32,
}
let mut map = HashMap::new();
map.insert(9, 10);
let mut test_struct = TestStruct {
tuple: (0, 1),
list: vec![2, 3, 4],
array: [5, 6, 7],
tuple_struct: TestTupleStruct(8),
e: TestEnum::A(11),
map,
value: 12,
}
.clone_value();
let test_struct = test_struct.downcast_mut::<DynamicStruct>().unwrap();
// test unknown DynamicStruct
let mut test_unknown_struct = DynamicStruct::default();
test_unknown_struct.insert("a", 13);
test_struct.insert("unknown_struct", test_unknown_struct);
// test unknown DynamicTupleStruct
let mut test_unknown_tuple_struct = DynamicTupleStruct::default();
test_unknown_tuple_struct.insert(14);
test_struct.insert("unknown_tuplestruct", test_unknown_tuple_struct);
assert_eq!(
format!("{:?}", test_struct),
"DynamicStruct(bevy_reflect::tests::TestStruct { \
tuple: DynamicTuple((0, 1)), \
tuple_struct: DynamicTupleStruct(bevy_reflect::tests::TestTupleStruct(8)), \
list: DynamicList([2, 3, 4]), \
array: DynamicArray([5, 6, 7]), \
e: DynamicEnum(A(11)), \
map: DynamicMap({9: 10}), \
value: 12, \
unknown_struct: DynamicStruct(_ { a: 13 }), \
unknown_tuplestruct: DynamicTupleStruct(_(14)) \
})"
);
}
#[test]
fn assert_impl_reflect_macro_on_all() {
struct Struct {
foo: (),
}
struct TupleStruct(());
enum Enum {
Foo { foo: () },
Bar(()),
}
impl_reflect!(
#[type_path = "my_crate::foo"]
struct Struct {
foo: (),
}
);
impl_reflect!(
#[type_path = "my_crate::foo"]
struct TupleStruct(());
);
impl_reflect!(
#[type_path = "my_crate::foo"]
enum Enum {
Foo { foo: () },
Bar(()),
}
);
assert_impl_all!(Struct: Reflect);
assert_impl_all!(TupleStruct: Reflect);
assert_impl_all!(Enum: Reflect);
}
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
#[cfg(feature = "glam")]
mod glam {
use super::*;
use ::glam::{quat, vec3, Quat, Vec3};
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
Migrate `Quat` reflection strategy from "value" to "struct" (#10068) Adopted from #8954, co-authored by @pyrotechnick # Objective The Bevy ecosystem currently reflects `Quat` via "value" rather than the more appropriate "struct" strategy. This behaviour is inconsistent to that of similar types, i.e. `Vec3`. Additionally, employing the "value" strategy causes instances of `Quat` to be serialised as a sequence `[x, y, z, w]` rather than structures of shape `{ x, y, z, w }`. The [comments surrounding the applicable code](https://github.com/bevyengine/bevy/blob/bec299fa6e727a59d973fc8ca8f468732d40cb14/crates/bevy_reflect/src/impls/glam.rs#L254) give context and historical reasons for this discrepancy: ``` // Quat fields are read-only (as of now), and reflection is currently missing // mechanisms for read-only fields. I doubt those mechanisms would be added, // so for now quaternions will remain as values. They are represented identically // to Vec4 and DVec4, so you may use those instead and convert between. ``` This limitation has [since been lifted by the upstream crate](https://github.com/bitshifter/glam-rs/commit/374625163ef51bbcac1f909f413a068b6ba4d1a0), glam. ## Solution Migrating the reflect strategy of Quat from "value" to "struct" via replacing `impl_reflect_value` with `impl_reflect_struct` resolves the issue. ## Changelog Migrated `Quat` reflection strategy to "struct" from "value" Migration Guide Changed Quat serialization/deserialization from sequences `[x, y, z, w]` to structures `{ x, y, z, w }`. --------- Co-authored-by: pyrotechnick <13998+pyrotechnick@users.noreply.github.com> Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-10-09 22:01:42 +00:00
#[test]
fn quat_serialization() {
let q = quat(1.0, 2.0, 3.0, 4.0);
let mut registry = TypeRegistry::default();
registry.register::<f32>();
registry.register::<Quat>();
let ser = ReflectSerializer::new(&q, &registry);
let config = PrettyConfig::default()
.new_line(String::from("\n"))
.indentor(String::from(" "));
let output = to_string_pretty(&ser, config).unwrap();
let expected = r#"
{
"glam::Quat": (
x: 1.0,
y: 2.0,
z: 3.0,
w: 4.0,
),
}"#;
assert_eq!(expected, format!("\n{output}"));
}
#[test]
fn quat_deserialization() {
let data = r#"
{
"glam::Quat": (
x: 1.0,
y: 2.0,
z: 3.0,
w: 4.0,
),
}"#;
let mut registry = TypeRegistry::default();
registry.register::<Quat>();
registry.register::<f32>();
let de = UntypedReflectDeserializer::new(&registry);
let mut deserializer =
Deserializer::from_str(data).expect("Failed to acquire deserializer");
Migrate `Quat` reflection strategy from "value" to "struct" (#10068) Adopted from #8954, co-authored by @pyrotechnick # Objective The Bevy ecosystem currently reflects `Quat` via "value" rather than the more appropriate "struct" strategy. This behaviour is inconsistent to that of similar types, i.e. `Vec3`. Additionally, employing the "value" strategy causes instances of `Quat` to be serialised as a sequence `[x, y, z, w]` rather than structures of shape `{ x, y, z, w }`. The [comments surrounding the applicable code](https://github.com/bevyengine/bevy/blob/bec299fa6e727a59d973fc8ca8f468732d40cb14/crates/bevy_reflect/src/impls/glam.rs#L254) give context and historical reasons for this discrepancy: ``` // Quat fields are read-only (as of now), and reflection is currently missing // mechanisms for read-only fields. I doubt those mechanisms would be added, // so for now quaternions will remain as values. They are represented identically // to Vec4 and DVec4, so you may use those instead and convert between. ``` This limitation has [since been lifted by the upstream crate](https://github.com/bitshifter/glam-rs/commit/374625163ef51bbcac1f909f413a068b6ba4d1a0), glam. ## Solution Migrating the reflect strategy of Quat from "value" to "struct" via replacing `impl_reflect_value` with `impl_reflect_struct` resolves the issue. ## Changelog Migrated `Quat` reflection strategy to "struct" from "value" Migration Guide Changed Quat serialization/deserialization from sequences `[x, y, z, w]` to structures `{ x, y, z, w }`. --------- Co-authored-by: pyrotechnick <13998+pyrotechnick@users.noreply.github.com> Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-10-09 22:01:42 +00:00
let dynamic_struct = de
.deserialize(&mut deserializer)
.expect("Failed to deserialize");
let mut result = Quat::default();
result.apply(&*dynamic_struct);
assert_eq!(result, quat(1.0, 2.0, 3.0, 4.0));
}
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
#[test]
fn vec3_serialization() {
let v = vec3(12.0, 3.0, -6.9);
let mut registry = TypeRegistry::default();
registry.register::<f32>();
registry.register::<Vec3>();
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
let ser = ReflectSerializer::new(&v, &registry);
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
let config = PrettyConfig::default()
.new_line(String::from("\n"))
.indentor(String::from(" "));
let output = to_string_pretty(&ser, config).unwrap();
let expected = r#"
{
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
"glam::Vec3": (
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
x: 12.0,
y: 3.0,
z: -6.9,
),
}"#;
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
assert_eq!(expected, format!("\n{output}"));
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
}
#[test]
fn vec3_deserialization() {
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
let data = r#"
{
reflect: `TypePath` part 2 (#8768) # Objective - Followup to #7184. - ~Deprecate `TypeUuid` and remove its internal references.~ No longer part of this PR. - Use `TypePath` for the type registry, and (de)serialisation instead of `std::any::type_name`. - Allow accessing type path information behind proxies. ## Solution - Introduce methods on `TypeInfo` and friends for dynamically querying type path. These methods supersede the old `type_name` methods. - Remove `Reflect::type_name` in favor of `DynamicTypePath::type_path` and `TypeInfo::type_path_table`. - Switch all uses of `std::any::type_name` in reflection, non-debugging contexts to use `TypePath`. --- ## Changelog - Added `TypePathTable` for dynamically accessing methods on `TypePath` through `TypeInfo` and the type registry. - Removed `type_name` from all `TypeInfo`-like structs. - Added `type_path` and `type_path_table` methods to all `TypeInfo`-like structs. - Removed `Reflect::type_name` in favor of `DynamicTypePath::reflect_type_path` and `TypeInfo::type_path`. - Changed the signature of all `DynamicTypePath` methods to return strings with a static lifetime. ## Migration Guide - Rely on `TypePath` instead of `std::any::type_name` for all stability guarantees and for use in all reflection contexts, this is used through with one of the following APIs: - `TypePath::type_path` if you have a concrete type and not a value. - `DynamicTypePath::reflect_type_path` if you have an `dyn Reflect` value without a concrete type. - `TypeInfo::type_path` for use through the registry or if you want to work with the represented type of a `DynamicFoo`. - Remove `type_name` from manual `Reflect` implementations. - Use `type_path` and `type_path_table` in place of `type_name` on `TypeInfo`-like structs. - Use `get_with_type_path(_mut)` over `get_with_type_name(_mut)`. ## Note to reviewers I think if anything we were a little overzealous in merging #7184 and we should take that extra care here. In my mind, this is the "point of no return" for `TypePath` and while I think we all agree on the design, we should carefully consider if the finer details and current implementations are actually how we want them moving forward. For example [this incorrect `TypePath` implementation for `String`](https://github.com/soqb/bevy/blob/3fea3c6c0b5719dfbd3d4230f5282ec80d82556a/crates/bevy_reflect/src/impls/std.rs#L90) (note that `String` is in the default Rust prelude) snuck in completely under the radar.
2023-10-09 19:33:03 +00:00
"glam::Vec3": (
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
x: 12.0,
y: 3.0,
z: -6.9,
),
}"#;
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
let mut registry = TypeRegistry::default();
registry.add_registration(Vec3::get_type_registration());
registry.add_registration(f32::get_type_registration());
bevy_reflect: Improve serialization format even more (#5723) > Note: This is rebased off #4561 and can be viewed as a competitor to that PR. See `Comparison with #4561` section for details. # Objective The current serialization format used by `bevy_reflect` is both verbose and error-prone. Taking the following structs[^1] for example: ```rust // -- src/inventory.rs #[derive(Reflect)] struct Inventory { id: String, max_storage: usize, items: Vec<Item> } #[derive(Reflect)] struct Item { name: String } ``` Given an inventory of a single item, this would serialize to something like: ```rust // -- assets/inventory.ron { "type": "my_game::inventory::Inventory", "struct": { "id": { "type": "alloc::string::String", "value": "inv001", }, "max_storage": { "type": "usize", "value": 10 }, "items": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "my_game::inventory::Item", "struct": { "name": { "type": "alloc::string::String", "value": "Pickaxe" }, }, }, ], }, }, } ``` Aside from being really long and difficult to read, it also has a few "gotchas" that users need to be aware of if they want to edit the file manually. A major one is the requirement that you use the proper keys for a given type. For structs, you need `"struct"`. For lists, `"list"`. For tuple structs, `"tuple_struct"`. And so on. It also ***requires*** that the `"type"` entry come before the actual data. Despite being a map— which in programming is almost always orderless by default— the entries need to be in a particular order. Failure to follow the ordering convention results in a failure to deserialize the data. This makes it very prone to errors and annoyances. ## Solution Using #4042, we can remove a lot of the boilerplate and metadata needed by this older system. Since we now have static access to type information, we can simplify our serialized data to look like: ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( name: "Pickaxe" ), ], ), } ``` This is much more digestible and a lot less error-prone (no more key requirements and no more extra type names). Additionally, it is a lot more familiar to users as it follows conventional serde mechanics. For example, the struct is represented with `(...)` when serialized to RON. #### Custom Serialization Additionally, this PR adds the opt-in ability to specify a custom serde implementation to be used rather than the one created via reflection. For example[^1]: ```rust // -- src/inventory.rs #[derive(Reflect, Serialize)] #[reflect(Serialize)] struct Item { #[serde(alias = "id")] name: String } ``` ```rust // -- assets/inventory.ron { "my_game::inventory::Inventory": ( id: "inv001", max_storage: 10, items: [ ( id: "Pickaxe" ), ], ), }, ``` By allowing users to define their own serialization methods, we do two things: 1. We give more control over how data is serialized/deserialized to the end user 2. We avoid having to re-define serde's attributes and forcing users to apply both (e.g. we don't need a `#[reflect(alias)]` attribute). ### Improved Formats One of the improvements this PR provides is the ability to represent data in ways that are more conventional and/or familiar to users. Many users are familiar with RON so here are some of the ways we can now represent data in RON: ###### Structs ```js { "my_crate::Foo": ( bar: 123 ) } // OR { "my_crate::Foo": Foo( bar: 123 ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Foo", "struct": { "bar": { "type": "usize", "value": 123 } } } ``` </details> ###### Tuples ```js { "(f32, f32)": (1.0, 2.0) } ``` <details> <summary>Old Format</summary> ```js { "type": "(f32, f32)", "tuple": [ { "type": "f32", "value": 1.0 }, { "type": "f32", "value": 2.0 } ] } ``` </details> ###### Tuple Structs ```js { "my_crate::Bar": ("Hello World!") } // OR { "my_crate::Bar": Bar("Hello World!") } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::Bar", "tuple_struct": [ { "type": "alloc::string::String", "value": "Hello World!" } ] } ``` </details> ###### Arrays It may be a bit surprising to some, but arrays now also use the tuple format. This is because they essentially _are_ tuples (a sequence of values with a fixed size), but only allow for homogenous types. Additionally, this is how RON handles them and is probably a result of the 32-capacity limit imposed on them (both by [serde](https://docs.rs/serde/latest/serde/trait.Serialize.html#impl-Serialize-for-%5BT%3B%2032%5D) and by [bevy_reflect](https://docs.rs/bevy/latest/bevy/reflect/trait.GetTypeRegistration.html#impl-GetTypeRegistration-for-%5BT%3B%2032%5D)). ```js { "[i32; 3]": (1, 2, 3) } ``` <details> <summary>Old Format</summary> ```js { "type": "[i32; 3]", "array": [ { "type": "i32", "value": 1 }, { "type": "i32", "value": 2 }, { "type": "i32", "value": 3 } ] } ``` </details> ###### Enums To make things simple, I'll just put a struct variant here, but the style applies to all variant types: ```js { "my_crate::ItemType": Consumable( name: "Healing potion" ) } ``` <details> <summary>Old Format</summary> ```js { "type": "my_crate::ItemType", "enum": { "variant": "Consumable", "struct": { "name": { "type": "alloc::string::String", "value": "Healing potion" } } } } ``` </details> ### Comparison with #4561 This PR is a rebased version of #4561. The reason for the split between the two is because this PR creates a _very_ different scene format. You may notice that the PR descriptions for either PR are pretty similar. This was done to better convey the changes depending on which (if any) gets merged first. If #4561 makes it in first, I will update this PR description accordingly. --- ## Changelog * Re-worked serialization/deserialization for reflected types * Added `TypedReflectDeserializer` for deserializing data with known `TypeInfo` * Renamed `ReflectDeserializer` to `UntypedReflectDeserializer` * ~~Replaced usages of `deserialize_any` with `deserialize_map` for non-self-describing formats~~ Reverted this change since there are still some issues that need to be sorted out (in a separate PR). By reverting this, crates like `bincode` can throw an error when attempting to deserialize non-self-describing formats (`bincode` results in `DeserializeAnyNotSupported`) * Structs, tuples, tuple structs, arrays, and enums are now all de/serialized using conventional serde methods ## Migration Guide * This PR reduces the verbosity of the scene format. Scenes will need to be updated accordingly: ```js // Old format { "type": "my_game::item::Item", "struct": { "id": { "type": "alloc::string::String", "value": "bevycraft:stone", }, "tags": { "type": "alloc::vec::Vec<alloc::string::String>", "list": [ { "type": "alloc::string::String", "value": "material" }, ], }, } // New format { "my_game::item::Item": ( id: "bevycraft:stone", tags: ["material"] ) } ``` [^1]: Some derives omitted for brevity.
2022-09-20 19:38:18 +00:00
let de = UntypedReflectDeserializer::new(&registry);
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
let mut deserializer =
Deserializer::from_str(data).expect("Failed to acquire deserializer");
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
let dynamic_struct = de
.deserialize(&mut deserializer)
.expect("Failed to deserialize");
let mut result = Vec3::default();
result.apply(&*dynamic_struct);
assert_eq!(result, vec3(12.0, 3.0, -6.9));
}
#[test]
fn vec3_field_access() {
let mut v = vec3(1.0, 2.0, 3.0);
assert_eq!(*v.get_field::<f32>("x").unwrap(), 1.0);
*v.get_field_mut::<f32>("y").unwrap() = 6.0;
assert_eq!(v.y, 6.0);
}
#[test]
fn vec3_path_access() {
let mut v = vec3(1.0, 2.0, 3.0);
bevy_reflect: Pre-parsed paths (#7321) # Objective > ℹ️ **This is an adoption of #4081 by @james7132** Fixes #4080. Provide a way to pre-parse reflection paths so as to avoid having to parse at each call to `GetPath::path` (or similar method). ## Solution Adds the `ParsedPath` struct (named `FieldPath` in the original PR) that parses and caches the sequence of accesses to a reflected element. This is functionally similar to the `GetPath` trait, but removes the need to parse an unchanged path more than once. ### Additional Changes Included in this PR from the original is cleaner code as well as the introduction of a new pathing operation: field access by index. This allows struct and struct variant fields to be accessed in a more performant (albeit more fragile) way if needed. This operation is faster due to not having to perform string matching. As an example, if we wanted the third field on a struct, we'd write `#2`—where `#` denotes indexed access and `2` denotes the desired field index. This PR also contains improved documentation for `GetPath` and friends, including renaming some of the methods to be more clear to the end-user with a reduced risk of getting them mixed up. ### Future Work There are a few things that could be done as a separate PR (order doesn't matter— they could be followup PRs or done in parallel). These are: - [x] ~~Add support for `Tuple`. Currently, we hint that they work but they do not.~~ See #7324 - [ ] Cleanup `ReflectPathError`. I think it would be nicer to give `ReflectPathError` two variants: `ReflectPathError::ParseError` and `ReflectPathError::AccessError`, with all current variants placed within one of those two. It's not obvious when one might expect to receive one type of error over the other, so we can help by explicitly categorizing them. --- ## Changelog - Cleaned up `GetPath` logic - Added `ParsedPath` for cached reflection paths - Added new reflection path syntax: struct field access by index (example syntax: `foo#1`) - Renamed methods on `GetPath`: - `path` -> `reflect_path` - `path_mut` -> `reflect_path_mut` - `get_path` -> `path` - `get_path_mut` -> `path_mut` ## Migration Guide `GetPath` methods have been renamed according to the following: - `path` -> `reflect_path` - `path_mut` -> `reflect_path_mut` - `get_path` -> `path` - `get_path_mut` -> `path_mut` Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2023-01-22 23:35:33 +00:00
assert_eq!(
*v.reflect_path("x").unwrap().downcast_ref::<f32>().unwrap(),
1.0
);
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
bevy_reflect: Pre-parsed paths (#7321) # Objective > ℹ️ **This is an adoption of #4081 by @james7132** Fixes #4080. Provide a way to pre-parse reflection paths so as to avoid having to parse at each call to `GetPath::path` (or similar method). ## Solution Adds the `ParsedPath` struct (named `FieldPath` in the original PR) that parses and caches the sequence of accesses to a reflected element. This is functionally similar to the `GetPath` trait, but removes the need to parse an unchanged path more than once. ### Additional Changes Included in this PR from the original is cleaner code as well as the introduction of a new pathing operation: field access by index. This allows struct and struct variant fields to be accessed in a more performant (albeit more fragile) way if needed. This operation is faster due to not having to perform string matching. As an example, if we wanted the third field on a struct, we'd write `#2`—where `#` denotes indexed access and `2` denotes the desired field index. This PR also contains improved documentation for `GetPath` and friends, including renaming some of the methods to be more clear to the end-user with a reduced risk of getting them mixed up. ### Future Work There are a few things that could be done as a separate PR (order doesn't matter— they could be followup PRs or done in parallel). These are: - [x] ~~Add support for `Tuple`. Currently, we hint that they work but they do not.~~ See #7324 - [ ] Cleanup `ReflectPathError`. I think it would be nicer to give `ReflectPathError` two variants: `ReflectPathError::ParseError` and `ReflectPathError::AccessError`, with all current variants placed within one of those two. It's not obvious when one might expect to receive one type of error over the other, so we can help by explicitly categorizing them. --- ## Changelog - Cleaned up `GetPath` logic - Added `ParsedPath` for cached reflection paths - Added new reflection path syntax: struct field access by index (example syntax: `foo#1`) - Renamed methods on `GetPath`: - `path` -> `reflect_path` - `path_mut` -> `reflect_path_mut` - `get_path` -> `path` - `get_path_mut` -> `path_mut` ## Migration Guide `GetPath` methods have been renamed according to the following: - `path` -> `reflect_path` - `path_mut` -> `reflect_path_mut` - `get_path` -> `path` - `get_path_mut` -> `path_mut` Co-authored-by: Gino Valente <gino.valente.code@gmail.com>
2023-01-22 23:35:33 +00:00
*v.reflect_path_mut("y")
.unwrap()
.downcast_mut::<f32>()
.unwrap() = 6.0;
Add macro to implement reflect for struct types and migrate glam types (#4540) # Objective Relevant issue: #4474 Currently glam types implement Reflect as a value, which is problematic for reflection, making scripting/editor work much more difficult. This PR re-implements them as structs. ## Solution Added a new proc macro, `impl_reflect_struct`, which replaces `impl_reflect_value` and `impl_from_reflect_value` for glam types. This macro could also be used for other types, but I don't know of any that would require it. It's specifically useful for foreign types that cannot derive Reflect normally. --- ## Changelog ### Added - `impl_reflect_struct` proc macro ### Changed - Glam reflect impls have been replaced with `impl_reflect_struct` - from_reflect's `impl_struct` altered to take an optional custom constructor, allowing non-default non-constructible foreign types to use it - Calls to `impl_struct` altered to conform to new signature - Altered glam types (All vec/mat combinations) have a different serialization structure, as they are reflected differently now. ## Migration Guide This will break altered glam types serialized to RON scenes, as they will expect to be serialized/deserialized as structs rather than values now. A future PR to add custom serialization for non-value types is likely on the way to restore previous behavior. Additionally, calls to `impl_struct` must add a `None` parameter to the end of the call to restore previous behavior. Co-authored-by: PROMETHIA-27 <42193387+PROMETHIA-27@users.noreply.github.com>
2022-05-09 16:32:15 +00:00
assert_eq!(v.y, 6.0);
}
#[test]
fn vec3_apply_dynamic() {
let mut v = vec3(3.0, 3.0, 3.0);
let mut d = DynamicStruct::default();
d.insert("x", 4.0f32);
d.insert("y", 2.0f32);
d.insert("z", 1.0f32);
v.apply(&d);
assert_eq!(v, vec3(4.0, 2.0, 1.0));
}
}
2020-11-28 00:39:59 +00:00
}