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89 commits

Author SHA1 Message Date
Mark Wainwright
f0a8994f55
Split WorldQuery into WorldQueryData and WorldQueryFilter (#9918)
# Objective

- Fixes #7680
- This is an updated for https://github.com/bevyengine/bevy/pull/8899
which had the same objective but fell a long way behind the latest
changes


## Solution

The traits `WorldQueryData : WorldQuery` and `WorldQueryFilter :
WorldQuery` have been added and some of the types and functions from
`WorldQuery` has been moved into them.

`ReadOnlyWorldQuery` has been replaced with `ReadOnlyWorldQueryData`. 

`WorldQueryFilter` is safe (as long as `WorldQuery` is implemented
safely).

`WorldQueryData` is unsafe - safely implementing it requires that
`Self::ReadOnly` is a readonly version of `Self` (this used to be a
safety requirement of `WorldQuery`)

The type parameters `Q` and `F` of `Query` must now implement
`WorldQueryData` and `WorldQueryFilter` respectively.

This makes it impossible to accidentally use a filter in the data
position or vice versa which was something that could lead to bugs.
~~Compile failure tests have been added to check this.~~

It was previously sometimes useful to use `Option<With<T>>` in the data
position. Use `Has<T>` instead in these cases.

The `WorldQuery` derive macro has been split into separate derive macros
for `WorldQueryData` and `WorldQueryFilter`.

Previously it was possible to derive both `WorldQuery` for a struct that
had a mixture of data and filter items. This would not work correctly in
some cases but could be a useful pattern in others. *This is no longer
possible.*

---

## Notes

- The changes outside of `bevy_ecs` are all changing type parameters to
the new types, updating the macro use, or replacing `Option<With<T>>`
with `Has<T>`.

- All `WorldQueryData` types always returned `true` for `IS_ARCHETYPAL`
so I moved it to `WorldQueryFilter` and
replaced all calls to it with `true`. That should be the only logic
change outside of the macro generation code.

- `Changed<T>` and `Added<T>` were being generated by a macro that I
have expanded. Happy to revert that if desired.

- The two derive macros share some functions for implementing
`WorldQuery` but the tidiest way I could find to implement them was to
give them a ton of arguments and ask clippy to ignore that.

## Changelog

### Changed
- Split `WorldQuery` into `WorldQueryData` and `WorldQueryFilter` which
now have separate derive macros. It is not possible to derive both for
the same type.
- `Query` now requires that the first type argument implements
`WorldQueryData` and the second implements `WorldQueryFilter`

## Migration Guide

- Update derives

```rust
// old
#[derive(WorldQuery)]
#[world_query(mutable, derive(Debug))]
struct CustomQuery {
    entity: Entity,
    a: &'static mut ComponentA
}

#[derive(WorldQuery)]
struct QueryFilter {
    _c: With<ComponentC>
}

// new 
#[derive(WorldQueryData)]
#[world_query_data(mutable, derive(Debug))]
struct CustomQuery {
    entity: Entity,
    a: &'static mut ComponentA,
}

#[derive(WorldQueryFilter)]
struct QueryFilter {
    _c: With<ComponentC>
}
```
- Replace `Option<With<T>>` with `Has<T>`

```rust
/// old
fn my_system(query: Query<(Entity, Option<With<ComponentA>>)>)
{
  for (entity, has_a_option) in query.iter(){
    let has_a:bool = has_a_option.is_some();
    //todo!()
  }
}

/// new
fn my_system(query: Query<(Entity, Has<ComponentA>)>)
{
  for (entity, has_a) in query.iter(){
    //todo!()
  }
}
```

- Fix queries which had filters in the data position or vice versa.

```rust
// old
fn my_system(query: Query<(Entity, With<ComponentA>)>)
{
  for (entity, _) in query.iter(){
  //todo!()
  }
}

// new
fn my_system(query: Query<Entity, With<ComponentA>>)
{
  for entity in query.iter(){
  //todo!()
  }
}

// old
fn my_system(query: Query<AnyOf<(&ComponentA, With<ComponentB>)>>)
{
  for (entity, _) in query.iter(){
  //todo!()
  }
}

// new
fn my_system(query: Query<Option<&ComponentA>, Or<(With<ComponentA>, With<ComponentB>)>>)
{
  for entity in query.iter(){
  //todo!()
  }
}

```

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
2023-11-28 03:56:07 +00:00
Konstantin Kostiuk
eeb0c2f2e4
Allow #[derive(Bundle)] on tuple structs (take 3) (#10561)
- rework of old @Veykril's work in
[2499](https://github.com/bevyengine/bevy/pull/2499)
- Fixes [3537](https://github.com/bevyengine/bevy/issues/3537)
2023-11-21 01:09:16 +00:00
Edgar Geier
a830530be4
Replace all labels with interned labels (#7762)
# Objective

First of all, this PR took heavy inspiration from #7760 and #5715. It
intends to also fix #5569, but with a slightly different approach.


This also fixes #9335 by reexporting `DynEq`.

## Solution

The advantage of this API is that we can intern a value without
allocating for zero-sized-types and for enum variants that have no
fields. This PR does this automatically in the `SystemSet` and
`ScheduleLabel` derive macros for unit structs and fieldless enum
variants. So this should cover many internal and external use cases of
`SystemSet` and `ScheduleLabel`. In these optimal use cases, no memory
will be allocated.

- The interning returns a `Interned<dyn SystemSet>`, which is just a
wrapper around a `&'static dyn SystemSet`.
- `Hash` and `Eq` are implemented in terms of the pointer value of the
reference, similar to my first approach of anonymous system sets in
#7676.
- Therefore, `Interned<T>` does not implement `Borrow<T>`, only `Deref`.
- The debug output of `Interned<T>` is the same as the interned value.

Edit: 
- `AppLabel` is now also interned and the old
`derive_label`/`define_label` macros were replaced with the new
interning implementation.
- Anonymous set ids are reused for different `Schedule`s, reducing the
amount of leaked memory.

### Pros
- `InternedSystemSet` and `InternedScheduleLabel` behave very similar to
the current `BoxedSystemSet` and `BoxedScheduleLabel`, but can be copied
without an allocation.
- Many use cases don't allocate at all.
- Very fast lookups and comparisons when using `InternedSystemSet` and
`InternedScheduleLabel`.
- The `intern` module might be usable in other areas.
- `Interned{ScheduleLabel, SystemSet, AppLabel}` does implement
`{ScheduleLabel, SystemSet, AppLabel}`, increasing ergonomics.

### Cons
- Implementors of `SystemSet` and `ScheduleLabel` still need to
implement `Hash` and `Eq` (and `Clone`) for it to work.

## Changelog

### Added

- Added `intern` module to `bevy_utils`.
- Added reexports of `DynEq` to `bevy_ecs` and `bevy_app`.

### Changed

- Replaced `BoxedSystemSet` and `BoxedScheduleLabel` with
`InternedSystemSet` and `InternedScheduleLabel`.
- Replaced `impl AsRef<dyn ScheduleLabel>` with `impl ScheduleLabel`.
- Replaced `AppLabelId` with `InternedAppLabel`.
- Changed `AppLabel` to use `Debug` for error messages.
- Changed `AppLabel` to use interning.
- Changed `define_label`/`derive_label` to use interning. 
- Replaced `define_boxed_label`/`derive_boxed_label` with
`define_label`/`derive_label`.
- Changed anonymous set ids to be only unique inside a schedule, not
globally.
- Made interned label types implement their label trait. 

### Removed

- Removed `define_boxed_label` and `derive_boxed_label`. 

## Migration guide

- Replace `BoxedScheduleLabel` and `Box<dyn ScheduleLabel>` with
`InternedScheduleLabel` or `Interned<dyn ScheduleLabel>`.
- Replace `BoxedSystemSet` and `Box<dyn SystemSet>` with
`InternedSystemSet` or `Interned<dyn SystemSet>`.
- Replace `AppLabelId` with `InternedAppLabel` or `Interned<dyn
AppLabel>`.
- Types manually implementing `ScheduleLabel`, `AppLabel` or `SystemSet`
need to implement:
  - `dyn_hash` directly instead of implementing `DynHash`
  - `as_dyn_eq`
- Pass labels to `World::try_schedule_scope`, `World::schedule_scope`,
`World::try_run_schedule`. `World::run_schedule`, `Schedules::remove`,
`Schedules::remove_entry`, `Schedules::contains`, `Schedules::get` and
`Schedules::get_mut` by value instead of by reference.

---------

Co-authored-by: Joseph <21144246+JoJoJet@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2023-10-25 21:39:23 +00:00
Joseph
0716922165
ParamSets containing non-send parameters should also be non-send (#10211)
# Objective

Fix #10207

## Solution

Mark a `ParamSet`'s `SystemMeta` as non-send if any of its component
parameters are non-send.
2023-10-21 18:07:52 +00:00
Joseph
d5d355ae1f
Fix the clippy::explicit_iter_loop lint (#9834)
# Objective

Replace instances of

```rust
for x in collection.iter{_mut}() {
```

with

```rust
for x in &{mut} collection {
```

This also changes CI to no longer suppress this lint. Note that since
this lint only shows up when using clippy in pedantic mode, it was
probably unnecessary to suppress this lint in the first place.
2023-09-19 03:35:22 +00:00
Rob Parrett
a788e31ad5
Fix CI for Rust 1.72 (#9562)
# Objective

[Rust 1.72.0](https://blog.rust-lang.org/2023/08/24/Rust-1.72.0.html) is
now stable.

# Notes

- `let-else` formatting has arrived!
- I chose to allow `explicit_iter_loop` due to
https://github.com/rust-lang/rust-clippy/issues/11074.
  
We didn't hit any of the false positives that prevent compilation, but
fixing this did produce a lot of the "symbol soup" mentioned, e.g. `for
image in &mut *image_events {`.
  
  Happy to undo this if there's consensus the other way.

---------

Co-authored-by: François <mockersf@gmail.com>
2023-08-25 12:34:24 +00:00
CatThingy
89cbc78d3d
Require #[derive(Event)] on all Events (#7086)
# Objective

Be consistent with `Resource`s and `Components` and have `Event` types
be more self-documenting.
Although not susceptible to accidentally using a function instead of a
value due to `Event`s only being initialized by their type, much of the
same reasoning for removing the blanket impl on `Resource` also applies
here.

* Not immediately obvious if a type is intended to be an event
* Prevent invisible conflicts if the same third-party or primitive types
are used as events
* Allows for further extensions (e.g. opt-in warning for missed events)

## Solution

Remove the blanket impl for the `Event` trait. Add a derive macro for
it.

---

## Changelog

- `Event` is no longer implemented for all applicable types. Add the
`#[derive(Event)]` macro for events.

## Migration Guide

* Add the `#[derive(Event)]` macro for events. Third-party types used as
events should be wrapped in a newtype.
2023-06-06 14:44:32 +00:00
François
0736195a1e
update syn, encase, glam and hexasphere (#8573)
# Objective

- Fixes #8282 
- Update `syn` to 2.0, `encase` to 0.6, `glam` to 0.24 and `hexasphere`
to 9.0


Blocked ~~on https://github.com/teoxoy/encase/pull/42~~ and ~~on
https://github.com/OptimisticPeach/hexasphere/pull/17~~

---------

Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
2023-05-16 01:24:17 +00:00
JoJoJet
3442a13d2c
Use UnsafeWorldCell to increase code quality for SystemParam (#8174)
# Objective

The type `&World` is currently in an awkward place, since it has two
meanings:
1. Read-only access to the entire world.
2. Interior mutable access to the world; immutable and/or mutable access
to certain portions of world data.

This makes `&World` difficult to reason about, and surprising to see in
function signatures if one does not know about the interior mutable
property.

The type `UnsafeWorldCell` was added in #6404, which is meant to
alleviate this confusion by adding a dedicated type for interior mutable
world access. However, much of the engine still treats `&World` as an
interior mutable-ish type. One of those places is `SystemParam`.

## Solution

Modify `SystemParam::get_param` to accept `UnsafeWorldCell` instead of
`&World`. Simplify the safety invariants, since the `UnsafeWorldCell`
type encapsulates the concept of constrained world access.

---

## Changelog

`SystemParam::get_param` now accepts an `UnsafeWorldCell` instead of
`&World`. This type provides a high-level API for unsafe interior
mutable world access.

## Migration Guide

For manual implementers of `SystemParam`: the function `get_item` now
takes `UnsafeWorldCell` instead of `&World`. To access world data, use:

* `.get_entity()`, which returns an `UnsafeEntityCell` which can be used
to access component data.
* `get_resource()` and its variants, to access resource data.
2023-04-01 15:45:07 +00:00
JoJoJet
a954f3e150
Remove #[system_param(ignore)] and #[world_query(ignore)] (#8265)
# Objective

Follow-up to #8030.

Now that `SystemParam` and `WorldQuery` are implemented for
`PhantomData`, the `ignore` attributes are now unnecessary.

---

## Changelog

- Removed the attributes `#[system_param(ignore)]` and
`#[world_query(ignore)]`.

## Migration Guide

The attributes `#[system_param(ignore)]` and `#[world_query]` ignore
have been removed. If you were using either of these with `PhantomData`
fields, you can simply remove the attribute:

```rust
#[derive(SystemParam)]
struct MyParam<'w, 's, Marker> {
    ...
    // Before:
    #[system_param(ignore)
    _marker: PhantomData<Marker>,

    // After:
    _marker: PhantomData<Marker>,
}
#[derive(WorldQuery)]
struct MyQuery<Marker> {
    ...
    // Before:
    #[world_query(ignore)
    _marker: PhantomData<Marker>,

    // After:
    _marker: PhantomData<Marker>,
}
```

If you were using this for another type that implements `Default`,
consider wrapping that type in `Local<>` (this only works for
`SystemParam`):

```rust
#[derive(SystemParam)]
struct MyParam<'w, 's> {
    // Before:
    #[system_param(ignore)]
    value: MyDefaultType, // This will be initialized using `Default` each time `MyParam` is created.

    // After:
    value: Local<MyDefaultType>, // This will be initialized using `Default` the first time `MyParam` is created.
}
```

If you are implementing either trait and need to preserve the exact
behavior of the old `ignore` attributes, consider manually implementing
`SystemParam` or `WorldQuery` for a wrapper struct that uses the
`Default` trait:

```rust
// Before:

#[derive(WorldQuery)
struct MyQuery {
   #[world_query(ignore)]
    str: String,
}

// After:

#[derive(WorldQuery)
struct MyQuery {
    str: DefaultQuery<String>,
}

pub struct DefaultQuery<T: Default>(pub T);

unsafe impl<T: Default> WorldQuery for DefaultQuery<T> {
    type Item<'w> = Self;
    ...
    unsafe fn fetch<'w>(...) -> Self::Item<'w> {
        Self(T::default())
    }
}
```
2023-03-30 23:02:25 +00:00
JoJoJet
d9113cca6f
Make #[system_param(ignore)] and #[world_query(ignore)] unnecessary (#8030)
# Objective

When using `PhantomData` fields with the `#[derive(SystemParam)]` or
`#[derive(WorldQuery)]` macros, the user is required to add the
`#[system_param(ignore)]` attribute so that the macro knows to treat
that field specially. This is undesirable, since it makes the macro more
fragile and less consistent.

## Solution

Implement `SystemParam` and `WorldQuery` for `PhantomData`. This makes
the `ignore` attributes unnecessary.

Some internal changes make the derive macro compatible with types that
have invariant lifetimes, which fixes #8192. From what I can tell, this
fix requires `PhantomData` to implement `SystemParam` in order to ensure
that all of a type's generic parameters are always constrained.

---

## Changelog

+ Implemented `SystemParam` and `WorldQuery` for `PhantomData<T>`.
+ Fixed a miscompilation caused when invariant lifetimes were used with
the `SystemParam` macro.
2023-03-30 15:12:26 +00:00
JoJoJet
27f2265e11
Fix name conflicts caused by the SystemParam and WorldQuery macros (#8012)
# Objective

Fix #1727
Fix #8010

Meta types generated by the `SystemParam` and `WorldQuery` derive macros
can conflict with user-defined types if they happen to have the same
name.

## Solution

In order to check if an identifier would conflict with user-defined
types, we can just search the original `TokenStream` passed to the macro
to see if it contains the identifier (since the meta types are defined
in an anonymous scope, it's only possible for them to conflict with the
struct definition itself). When generating an identifier for meta types,
we can simply check if it would conflict, and then add additional
characters to the name until it no longer conflicts with anything.

The `WorldQuery` "Item" and read-only structs are a part of a module's
public API, and thus it is intended for them to conflict with
user-defined types.
2023-03-22 15:45:25 +00:00
Jakub Łabor
caa662272c
bevy_ecs: add untyped methods for inserting components and bundles (#7204)
This MR is a rebased and alternative proposal to
https://github.com/bevyengine/bevy/pull/5602

# Objective

- https://github.com/bevyengine/bevy/pull/4447 implemented untyped
(using component ids instead of generics and TypeId) APIs for
inserting/accessing resources and accessing components, but left
inserting components for another PR (this one)

## Solution

- add `EntityMut::insert_by_id`

- split `Bundle` into `DynamicBundle` with `get_components` and `Bundle:
DynamicBundle`. This allows the `BundleInserter` machinery to be reused
for bundles that can only be written, not read, and have no statically
available `ComponentIds`

- Compared to the original MR this approach exposes unsafe endpoints and
requires the user to manage instantiated `BundleIds`. This is quite easy
for the end user to do and does not incur the performance penalty of
checking whether component input is correctly provided for the
`BundleId`.

- This MR does ensure that constructing `BundleId` itself is safe

---

## Changelog

- add methods for inserting bundles and components to:
`world.entity_mut(entity).insert_by_id`
2023-03-21 00:33:11 +00:00
Carter Anderson
aefe1f0739
Schedule-First: the new and improved add_systems (#8079)
Co-authored-by: Mike <mike.hsu@gmail.com>
2023-03-18 01:45:34 +00:00
JoJoJet
2e7b915ba4
Increase type safety and clarity for change detection (#7905) 2023-03-09 17:17:02 +00:00
dis-da-moe
8853bef6df implement TypeUuid for primitives and fix multiple-parameter generics having the same TypeUuid (#6633)
# Objective

- Fixes #5432 
- Fixes #6680

## Solution

- move code responsible for generating the `impl TypeUuid` from `type_uuid_derive` into a new function, `gen_impl_type_uuid`.
- this allows the new proc macro, `impl_type_uuid`, to call the code for generation.
- added struct `TypeUuidDef` and implemented `syn::Parse` to allow parsing of the input for the new macro.
- finally, used the new macro `impl_type_uuid` to implement `TypeUuid` for the standard library (in `crates/bevy_reflect/src/type_uuid_impl.rs`).
- fixes #6680 by doing a wrapping add of the param's index to its `TYPE_UUID`

Co-authored-by: dis-da-moe <84386186+dis-da-moe@users.noreply.github.com>
2023-02-16 17:09:44 +00:00
SpecificProtagonist
6314f50e7b States derive macro (#7535)
# Objective
Implementing `States` manually is repetitive, so let's not.

One thing I'm unsure of is whether the macro import statement is in the right place.
2023-02-07 14:02:21 +00:00
张林伟
aa4170d9a4 Rename schedule v3 to schedule (#7519)
# Objective

- Follow up of https://github.com/bevyengine/bevy/pull/7267

## Solution

- Rename schedule_v3 to schedule
- Suppress "module inception" lint
2023-02-06 18:44:40 +00:00
Carter Anderson
dcc03724a5 Base Sets (#7466)
# Objective

NOTE: This depends on #7267 and should not be merged until #7267 is merged. If you are reviewing this before that is merged, I highly recommend viewing the Base Sets commit instead of trying to find my changes amongst those from #7267.

"Default sets" as described by the [Stageless RFC](https://github.com/bevyengine/rfcs/pull/45) have some [unfortunate consequences](https://github.com/bevyengine/bevy/discussions/7365).

## Solution

This adds "base sets" as a variant of `SystemSet`:

A set is a "base set" if `SystemSet::is_base` returns `true`. Typically this will be opted-in to using the `SystemSet` derive:

```rust
#[derive(SystemSet, Clone, Hash, Debug, PartialEq, Eq)]
#[system_set(base)]
enum MyBaseSet {
  A,
  B,
}
``` 

**Base sets are exclusive**: a system can belong to at most one "base set". Adding a system to more than one will result in an error. When possible we fail immediately during system-config-time with a nice file + line number. For the more nested graph-ey cases, this will fail at the final schedule build. 

**Base sets cannot belong to other sets**: this is where the word "base" comes from

Systems and Sets can only be added to base sets using `in_base_set`. Calling `in_set` with a base set will fail. As will calling `in_base_set` with a normal set.

```rust
app.add_system(foo.in_base_set(MyBaseSet::A))
       // X must be a normal set ... base sets cannot be added to base sets
       .configure_set(X.in_base_set(MyBaseSet::A))
```

Base sets can still be configured like normal sets:

```rust
app.add_system(MyBaseSet::B.after(MyBaseSet::Ap))
``` 

The primary use case for base sets is enabling a "default base set":

```rust
schedule.set_default_base_set(CoreSet::Update)
  // this will belong to CoreSet::Update by default
  .add_system(foo)
  // this will override the default base set with PostUpdate
  .add_system(bar.in_base_set(CoreSet::PostUpdate))
```

This allows us to build apis that work by default in the standard Bevy style. This is a rough analog to the "default stage" model, but it use the new "stageless sets" model instead, with all of the ordering flexibility (including exclusive systems) that it provides.

---

## Changelog

- Added "base sets" and ported CoreSet to use them.

## Migration Guide

TODO
2023-02-06 03:10:08 +00:00
Alice Cecile
206c7ce219 Migrate engine to Schedule v3 (#7267)
Huge thanks to @maniwani, @devil-ira, @hymm, @cart, @superdump and @jakobhellermann for the help with this PR.

# Objective

- Followup #6587.
- Minimal integration for the Stageless Scheduling RFC: https://github.com/bevyengine/rfcs/pull/45

## Solution

- [x]  Remove old scheduling module
- [x] Migrate new methods to no longer use extension methods
- [x] Fix compiler errors
- [x] Fix benchmarks
- [x] Fix examples
- [x] Fix docs
- [x] Fix tests

## Changelog

### Added

- a large number of methods on `App` to work with schedules ergonomically
- the `CoreSchedule` enum
- `App::add_extract_system` via the `RenderingAppExtension` trait extension method
- the private `prepare_view_uniforms` system now has a public system set for scheduling purposes, called `ViewSet::PrepareUniforms`

### Removed

- stages, and all code that mentions stages
- states have been dramatically simplified, and no longer use a stack
- `RunCriteriaLabel`
- `AsSystemLabel` trait
- `on_hierarchy_reports_enabled` run criteria (now just uses an ad hoc resource checking run condition)
- systems in `RenderSet/Stage::Extract` no longer warn when they do not read data from the main world
- `RunCriteriaLabel`
- `transform_propagate_system_set`: this was a nonstandard pattern that didn't actually provide enough control. The systems are already `pub`: the docs have been updated to ensure that the third-party usage is clear.

### Changed

- `System::default_labels` is now `System::default_system_sets`.
- `App::add_default_labels` is now `App::add_default_sets`
- `CoreStage` and `StartupStage` enums are now `CoreSet` and `StartupSet`
- `App::add_system_set` was renamed to `App::add_systems`
- The `StartupSchedule` label is now defined as part of the `CoreSchedules` enum
-  `.label(SystemLabel)` is now referred to as `.in_set(SystemSet)`
- `SystemLabel` trait was replaced by `SystemSet`
- `SystemTypeIdLabel<T>` was replaced by `SystemSetType<T>`
- The `ReportHierarchyIssue` resource now has a public constructor (`new`), and implements `PartialEq`
- Fixed time steps now use a schedule (`CoreSchedule::FixedTimeStep`) rather than a run criteria.
- Adding rendering extraction systems now panics rather than silently failing if no subapp with the `RenderApp` label is found.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. 
- `SceneSpawnerSystem` now runs under `CoreSet::Update`, rather than `CoreStage::PreUpdate.at_end()`.
- `bevy_pbr::add_clusters` is no longer an exclusive system
- the top level `bevy_ecs::schedule` module was replaced with `bevy_ecs::scheduling`
- `tick_global_task_pools_on_main_thread` is no longer run as an exclusive system. Instead, it has been replaced by `tick_global_task_pools`, which uses a `NonSend` resource to force running on the main thread.

## Migration Guide

- Calls to `.label(MyLabel)` should be replaced with `.in_set(MySet)`
- Stages have been removed. Replace these with system sets, and then add command flushes using the `apply_system_buffers` exclusive system where needed.
- The `CoreStage`, `StartupStage, `RenderStage` and `AssetStage`  enums have been replaced with `CoreSet`, `StartupSet, `RenderSet` and `AssetSet`. The same scheduling guarantees have been preserved.
  - Systems are no longer added to `CoreSet::Update` by default. Add systems manually if this behavior is needed, although you should consider adding your game logic systems to `CoreSchedule::FixedTimestep` instead for more reliable framerate-independent behavior.
  - Similarly, startup systems are no longer part of `StartupSet::Startup` by default. In most cases, this won't matter to you.
  - For example, `add_system_to_stage(CoreStage::PostUpdate, my_system)` should be replaced with 
  - `add_system(my_system.in_set(CoreSet::PostUpdate)`
- When testing systems or otherwise running them in a headless fashion, simply construct and run a schedule using `Schedule::new()` and `World::run_schedule` rather than constructing stages
- Run criteria have been renamed to run conditions. These can now be combined with each other and with states.
- Looping run criteria and state stacks have been removed. Use an exclusive system that runs a schedule if you need this level of control over system control flow.
- For app-level control flow over which schedules get run when (such as for rollback networking), create your own schedule and insert it under the `CoreSchedule::Outer` label.
- Fixed timesteps are now evaluated in a schedule, rather than controlled via run criteria. The `run_fixed_timestep` system runs this schedule between `CoreSet::First` and `CoreSet::PreUpdate` by default.
- Command flush points introduced by `AssetStage` have been removed. If you were relying on these, add them back manually.
- Adding extract systems is now typically done directly on the main app. Make sure the `RenderingAppExtension` trait is in scope, then call `app.add_extract_system(my_system)`.
- the `calculate_bounds` system, with the `CalculateBounds` label, is now in `CoreSet::Update`, rather than in `CoreSet::PostUpdate` before commands are applied. You may need to order your movement systems to occur before this system in order to avoid system order ambiguities in culling behavior.
- the `RenderLabel` `AppLabel` was renamed to `RenderApp` for clarity
- `App::add_state` now takes 0 arguments: the starting state is set based on the `Default` impl.
- Instead of creating `SystemSet` containers for systems that run in stages, simply use `.on_enter::<State::Variant>()` or its `on_exit` or `on_update` siblings.
- `SystemLabel` derives should be replaced with `SystemSet`. You will also need to add the `Debug`, `PartialEq`, `Eq`, and `Hash` traits to satisfy the new trait bounds.
- `with_run_criteria` has been renamed to `run_if`. Run criteria have been renamed to run conditions for clarity, and should now simply return a bool.
- States have been dramatically simplified: there is no longer a "state stack". To queue a transition to the next state, call `NextState::set`

## TODO

- [x] remove dead methods on App and World
- [x] add `App::add_system_to_schedule` and `App::add_systems_to_schedule`
- [x] avoid adding the default system set at inappropriate times
- [x] remove any accidental cycles in the default plugins schedule
- [x] migrate benchmarks
- [x] expose explicit labels for the built-in command flush points
- [x] migrate engine code
- [x] remove all mentions of stages from the docs
- [x] verify docs for States
- [x] fix uses of exclusive systems that use .end / .at_start / .before_commands
- [x] migrate RenderStage and AssetStage
- [x] migrate examples
- [x] ensure that transform propagation is exported in a sufficiently public way (the systems are already pub)
- [x] ensure that on_enter schedules are run at least once before the main app
- [x] re-enable opt-in to execution order ambiguities
- [x] revert change to `update_bounds` to ensure it runs in `PostUpdate`
- [x] test all examples
  - [x] unbreak directional lights
  - [x] unbreak shadows (see 3d_scene, 3d_shape, lighting, transparaency_3d examples)
  - [x] game menu example shows loading screen and menu simultaneously
  - [x] display settings menu is a blank screen
  - [x] `without_winit` example panics
- [x] ensure all tests pass
  - [x] SubApp doc test fails
  - [x] runs_spawn_local tasks fails
  - [x] [Fix panic_when_hierachy_cycle test hanging](https://github.com/alice-i-cecile/bevy/pull/120)

## Points of Difficulty and Controversy

**Reviewers, please give feedback on these and look closely**

1.  Default sets, from the RFC, have been removed. These added a tremendous amount of implicit complexity and result in hard to debug scheduling errors. They're going to be tackled in the form of "base sets" by @cart in a followup.
2. The outer schedule controls which schedule is run when `App::update` is called.
3. I implemented `Label for `Box<dyn Label>` for our label types. This enables us to store schedule labels in concrete form, and then later run them. I ran into the same set of problems when working with one-shot systems. We've previously investigated this pattern in depth, and it does not appear to lead to extra indirection with nested boxes.
4. `SubApp::update` simply runs the default schedule once. This sucks, but this whole API is incomplete and this was the minimal changeset.
5. `time_system` and `tick_global_task_pools_on_main_thread` no longer use exclusive systems to attempt to force scheduling order
6. Implemetnation strategy for fixed timesteps
7. `AssetStage` was migrated to `AssetSet` without reintroducing command flush points. These did not appear to be used, and it's nice to remove these bottlenecks.
8. Migration of `bevy_render/lib.rs` and pipelined rendering. The logic here is unusually tricky, as we have complex scheduling requirements.

## Future Work (ideally before 0.10)

- Rename schedule_v3 module to schedule or scheduling
- Add a derive macro to states, and likely a `EnumIter` trait of some form
- Figure out what exactly to do with the "systems added should basically work by default" problem
- Improve ergonomics for working with fixed timesteps and states
- Polish FixedTime API to match Time
- Rebase and merge #7415
- Resolve all internal ambiguities (blocked on better tools, especially #7442)
- Add "base sets" to replace the removed default sets.
2023-02-06 02:04:50 +00:00
JoJoJet
44a572e4e6 Fix ignored lifetimes in #[derive(SystemParam)] (#7458)
# Objective

Fix #7447.

The `SystemParam` derive uses the wrong lifetimes for ignored fields.

## Solution

Use type inference instead of explicitly naming the types of ignored fields. This allows the compiler to automatically use the correct lifetime.
2023-02-03 09:17:48 +00:00
Cameron
684f07595f Add bevy_ecs::schedule_v3 module (#6587)
# Objective

Complete the first part of the migration detailed in bevyengine/rfcs#45.

## Solution

Add all the new stuff.

### TODO

- [x] Impl tuple methods.
- [x] Impl chaining.
- [x] Port ambiguity detection.
- [x] Write docs.
- [x] ~~Write more tests.~~(will do later)
- [ ] Write changelog and examples here?
- [x] ~~Replace `petgraph`.~~ (will do later)



Co-authored-by: james7132 <contact@jamessliu.com>
Co-authored-by: Michael Hsu <mike.hsu@gmail.com>
Co-authored-by: Mike Hsu <mike.hsu@gmail.com>
2023-01-17 01:39:17 +00:00
JoJoJet
fa40e2badb Fix a miscompilation with #[derive(SystemParam)] (#7105)
# Objective

- Fix #7103.
- The issue is caused because I forgot to add a where clause to a generated struct in #7056.

## Solution

- Add the where clause.
2023-01-10 18:41:50 +00:00
JoJoJet
1efdbb7e3e Remove the SystemParamState trait and remove types like ResState (#6919)
Spiritual successor to #5205.
Actual successor to #6865.

# Objective

Currently, system params are defined using three traits: `SystemParam`, `ReadOnlySystemParam`, `SystemParamState`. The behavior for each param is specified by the `SystemParamState` trait, while `SystemParam` simply defers to the state.

Splitting the traits in this way makes it easier to implement within macros, but it increases the cognitive load. Worst of all, this approach requires each `MySystemParam` to have a public `MySystemParamState` type associated with it.

## Solution

* Merge the trait `SystemParamState` into `SystemParam`.
* Remove all trivial `SystemParam` state types. 
  * `OptionNonSendMutState<T>`: you will not be missed.

---

- [x] Fix/resolve the remaining test failure.

## Changelog

* Removed the trait `SystemParamState`, merging its functionality into `SystemParam`.

## Migration Guide

**Note**: this should replace the migration guide for #6865.
This is relative to Bevy 0.9, not main.

The traits `SystemParamState` and `SystemParamFetch` have been removed, and their functionality has been transferred to `SystemParam`.


```rust
// Before (0.9)
impl SystemParam for MyParam<'_, '_> {
    type State = MyParamState;
}
unsafe impl SystemParamState for MyParamState {
    fn init(world: &mut World, system_meta: &mut SystemMeta) -> Self { ... }
}
unsafe impl<'w, 's> SystemParamFetch<'w, 's> for MyParamState {
    type Item = MyParam<'w, 's>;
    fn get_param(&mut self, ...) -> Self::Item;
}
unsafe impl ReadOnlySystemParamFetch for MyParamState { }

// After (0.10)
unsafe impl SystemParam for MyParam<'_, '_> {
    type State = MyParamState;
    type Item<'w, 's> = MyParam<'w, 's>;
    fn init_state(world: &mut World, system_meta: &mut SystemMeta) -> Self::State { ... }
    fn get_param<'w, 's>(state: &mut Self::State, ...) -> Self::Item<'w, 's>;
}
unsafe impl ReadOnlySystemParam for MyParam<'_, '_> { }
```

The trait `ReadOnlySystemParamFetch` has been replaced with `ReadOnlySystemParam`.

```rust
// Before
unsafe impl ReadOnlySystemParamFetch for MyParamState {}

// After
unsafe impl ReadOnlySystemParam for MyParam<'_, '_> {}
```
2023-01-07 23:20:32 +00:00
JoJoJet
8ca3d0462c Allow SystemParams with private fields (#7056)
# Objective

- Fix #4200

Currently, `#[derive(SystemParam)]` publicly exposes each field type, which makes it impossible to encapsulate private fields.

## Solution

Previously, the fields were leaked because they were used as an input generic type to the macro-generated `SystemParam::State` struct. That type has been changed to store its state in a field with a specific type, instead of a generic type.

---

## Changelog

- Fixed a bug that caused `#[derive(SystemParam)]` to leak the types of private fields.
2023-01-04 23:25:36 +00:00
JoJoJet
0d98327ce7 Support SystemParam types with const generics (#7001)
# Objective

* Currently, the `SystemParam` derive does not support types with const generic parameters.
  * If you try to use const generics, the error message is cryptic and unhelpful.
* Continuation of the work started in #6867 and #6957.

## Solution

Allow const generic parameters to be used with `#[derive(SystemParam)]`.
2022-12-25 00:06:23 +00:00
JoJoJet
fa2b5f2b36 Add documentation to ParamSet (#6998)
# Objective

Fixes #4729.
Continuation of #4854.

## Solution

Add documentation to `ParamSet` and its methods. Includes examples suggested by community members in the original PR.


Co-authored-by: Nanox19435 <50684926+Nanox19435@users.noreply.github.com>
Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
2022-12-25 00:06:22 +00:00
JoJoJet
025996b18c Lift the 16-field limit from the SystemParam derive (#6867)
# Objective

* The `SystemParam` derive internally uses tuples, which means it is constrained by the 16-field limit on `all_tuples`.
    * The error message if you exceed this limit is abysmal.
* Supercedes #5965 -- this does the same thing, but is simpler.

## Solution

If any tuples have more than 16 fields, they are folded into tuples of tuples until they are under the 16-field limit.
2022-12-21 01:54:10 +00:00
JoJoJet
0363e0b32a Support tuple structs with #[derive(SystemParam)] (#6957)
# Objective

Currently, only named structs can be used with the `SystemParam` derive macro.

## Solution

Remove the restriction. Tuple structs and unit structs are now supported.

---

## Changelog

+ Added support for tuple structs and unit structs to the `SystemParam` derive macro.
2022-12-20 23:45:44 +00:00
James Liu
79b9231b74 Move system_commands spans into apply_buffers (#6900)
# Objective
A separate `tracing` span for running a system's commands is created, even if the system doesn't have commands. This is adding extra measuring overhead (see #4892) where it's not needed.

## Solution
Move the span into `ParallelCommandState` and `CommandQueue`'s `SystemParamState::apply`. To get the right metadata for the span, a additional `&SystemMeta` parameter was added to `SystemParamState::apply`.

---

## Changelog
Added: `SystemMeta::name`
Changed: Systems without `Commands` and  `ParallelCommands` will no longer show a "system_commands" span when profiling.
Changed: `SystemParamState::apply` now takes a `&SystemMeta` parameter in addition to the provided `&mut World`.
2022-12-11 23:04:04 +00:00
James Liu
87bf0e2664 Remove unnecessary branching from bundle insertion (#6902)
# Objective
Speed up bundle insertion and spawning from a bundle.

## Solution
Use the same technique used in #6800 to remove the branch on storage type when writing components from a `Bundle` into storage.

 - Add a `StorageType` argument to the closure on `Bundle::get_components`.
 - Pass `C::Storage::STORAGE_TYPE` into that argument.
 - Match on that argument instead of reading from a `Vec<StorageType>` in `BundleInfo`.
 - Marked all implementations of `Bundle::get_components` as inline to encourage dead code elimination.

The `Vec<StorageType>` in `BundleInfo` was also removed as it's no longer needed. If users were reliant on this, they can either use the compile time constants or fetch the information from `Components`. Should save a rather negligible amount of memory.

## Performance
Microbenchmarks show a slight improvement to inserting components into existing entities, as well as spawning from a bundle. Ranging about 8-16% faster depending on the benchmark.

```
group                                          main                                    soft-constant-write-components
-----                                          ----                                    ------------------------------
add_remove/sparse_set                          1.08  1019.0±80.10µs        ? ?/sec     1.00   944.6±66.86µs        ? ?/sec
add_remove/table                               1.07  1343.3±20.37µs        ? ?/sec     1.00  1257.3±18.13µs        ? ?/sec
add_remove_big/sparse_set                      1.08  1132.4±263.10µs        ? ?/sec    1.00  1050.8±240.74µs        ? ?/sec
add_remove_big/table                           1.02      2.6±0.05ms        ? ?/sec     1.00      2.5±0.08ms        ? ?/sec
get_or_spawn/batched                           1.15   401.4±17.76µs        ? ?/sec     1.00   349.3±11.26µs        ? ?/sec
get_or_spawn/individual                        1.13   732.1±43.35µs        ? ?/sec     1.00   645.6±41.44µs        ? ?/sec
insert_commands/insert                         1.12   623.9±37.48µs        ? ?/sec     1.00   557.4±34.99µs        ? ?/sec
insert_commands/insert_batch                   1.16   401.4±17.00µs        ? ?/sec     1.00   347.4±12.87µs        ? ?/sec
insert_simple/base                             1.08    416.9±5.60µs        ? ?/sec     1.00    385.2±4.14µs        ? ?/sec
insert_simple/unbatched                        1.06   934.5±44.58µs        ? ?/sec     1.00   881.3±47.86µs        ? ?/sec
spawn_commands/2000_entities                   1.09   190.7±11.41µs        ? ?/sec     1.00    174.7±9.15µs        ? ?/sec
spawn_commands/4000_entities                   1.10   386.5±25.33µs        ? ?/sec     1.00   352.3±18.81µs        ? ?/sec
spawn_commands/6000_entities                   1.10   586.2±34.42µs        ? ?/sec     1.00   535.3±27.25µs        ? ?/sec
spawn_commands/8000_entities                   1.08   778.5±45.15µs        ? ?/sec     1.00   718.0±33.66µs        ? ?/sec
spawn_world/10000_entities                     1.04  1026.4±195.46µs        ? ?/sec    1.00  985.8±253.37µs        ? ?/sec
spawn_world/1000_entities                      1.06   103.8±20.23µs        ? ?/sec     1.00    97.6±18.22µs        ? ?/sec
spawn_world/100_entities                       1.15     11.4±4.25µs        ? ?/sec     1.00      9.9±1.87µs        ? ?/sec
spawn_world/10_entities                        1.05  1030.8±229.78ns        ? ?/sec    1.00  986.2±231.12ns        ? ?/sec
spawn_world/1_entities                         1.01   105.1±23.33ns        ? ?/sec     1.00   104.6±31.84ns        ? ?/sec
```

---

## Changelog
Changed: `Bundle::get_components` now takes a `FnMut(StorageType, OwningPtr)`. The provided storage type must be correct for the component being fetched.
2022-12-11 18:46:43 +00:00
JoJoJet
1af73624fa Simplify trait hierarchy for SystemParam (#6865)
# Objective

* Implementing a custom `SystemParam` by hand requires implementing three traits -- four if it is read-only.
* The trait `SystemParamFetch<'w, 's>` is a workaround from before we had generic associated types, and is no longer necessary.

## Solution

* Combine the trait `SystemParamFetch` with `SystemParamState`.
    * I decided to remove the `Fetch` name and keep the `State` name, since the former was consistently conflated with the latter.
* Replace the trait `ReadOnlySystemParamFetch` with `ReadOnlySystemParam`, which simplifies trait bounds in generic code.

---

## Changelog

- Removed the trait `SystemParamFetch`, moving its functionality to `SystemParamState`.
- Replaced the trait `ReadOnlySystemParamFetch` with `ReadOnlySystemParam`.

## Migration Guide

The trait `SystemParamFetch` has been removed, and its functionality has been transferred to `SystemParamState`.

```rust
// Before
impl SystemParamState for MyParamState {
    fn init(world: &mut World, system_meta: &mut SystemMeta) -> Self { ... }
}
impl<'w, 's> SystemParamFetch<'w, 's> for MyParamState {
    type Item = MyParam<'w, 's>;
    fn get_param(...) -> Self::Item;
}

// After
impl SystemParamState for MyParamState {
    type Item<'w, 's> = MyParam<'w, 's>; // Generic associated types!
    fn init(world: &mut World, system_meta: &mut SystemMeta) -> Self { ... }
    fn get_param<'w, 's>(...) -> Self::Item<'w, 's>;
}
```

The trait `ReadOnlySystemParamFetch` has been replaced with `ReadOnlySystemParam`.

```rust
// Before
unsafe impl ReadOnlySystemParamFetch for MyParamState {}

// After
unsafe impl<'w, 's> ReadOnlySystemParam for MyParam<'w, 's> {}
```
2022-12-11 18:34:14 +00:00
JoJoJet
05b498a224 Make the SystemParam derive macro more flexible (#6694)
# Objective

Currently, the `SystemParam` derive forces you to declare the lifetime parameters `<'w, 's>`, even if you don't use them.
If you don't follow this structure, the error message is quite nasty.

### Example (before):

```rust
#[derive(SystemParam)]
pub struct EventWriter<'w, 's, E: Event> {
    events: ResMut<'w, Events<E>>,
    // The derive forces us to declare the `'s` lifetime even though we don't use it,
    // so we have to add this `PhantomData` to please rustc.
    #[system_param(ignore)]
    _marker: PhantomData<&'s ()>,
}
```


## Solution

* Allow the user to omit either lifetime.
* Emit a descriptive error if any lifetimes used are invalid.

### Example (after):

```rust
#[derive(SystemParam)]
pub struct EventWriter<'w, E: Event> {
    events: ResMut<'w, Events<E>>,
}
```

---

## Changelog

* The `SystemParam` derive is now more flexible, allowing you to omit unused lifetime parameters.
2022-12-05 20:15:03 +00:00
Jakob Hellermann
e71c4d2802 fix nightly clippy warnings (#6395)
# Objective

- fix new clippy lints before they get stable and break CI

## Solution

- run `clippy --fix` to auto-fix machine-applicable lints
- silence `clippy::should_implement_trait` for `fn HandleId::default<T: Asset>`

## Changes
- always prefer `format!("{inline}")` over `format!("{}", not_inline)`
- prefer `Box::default` (or `Box::<T>::default` if necessary) over `Box::new(T::default())`
2022-10-28 21:03:01 +00:00
Marc-Stefan Cassola
7a41efa227 implemented #[bundle(ignore)] (#6123)
# Objective

Fixes #5559

Replaces #5628

## Solution

Because the generated method from_components() creates an instance of Self my implementation requires any field type that is marked to be ignored to implement Default.

---

## Changelog

Added the possibility to ignore fields in a bundle with `#[bundle(ignore)]`. Typically used when `PhantomData` needs to be added to a `Bundle`.
2022-10-24 14:33:45 +00:00
Daniel McNab
1a2aedd165 Implement Bundle for Component. Use Bundle tuples for insertion (#2975)
@BoxyUwU this is your fault. 

Also cart didn't arrive in time to tell us not to do this.

# Objective

- Fix #2974

## Solution

- The first commit just does the actual change
- Follow up commits do steps to prove that this method works to unify as required, but this does not remove `insert_bundle`.

## Changelog

### Changed
Nested bundles now collapse automatically, and every `Component` now implements `Bundle`.
This means that you can combine bundles and components arbitrarily, for example:
```rust
// before:
.insert(A).insert_bundle(MyBBundle{..})
// after:
.insert_bundle((A, MyBBundle {..}))
```

Note that there will be a follow up PR that removes the current `insert` impl and renames `insert_bundle` to `insert`.

### Removed
The `bundle` attribute in `derive(Bundle)`.

## Migration guide

In `derive(Bundle)`, the `bundle` attribute has been removed. Nested bundles are not collapsed automatically. You should remove `#[bundle]` attributes.

Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-09-20 20:17:08 +00:00
Alice Cecile
c96b7ffb50 Remove ambiguity sets (#5916)
# Objective

Ambiguity sets are used to ignore system order ambiguities between groups of systems. However, they are not very useful: they are clunky, poorly integrated, and generally hampered by the difficulty using (or discovering) the ambiguity detector.

As a first step to the work in #4299, we're removing them.

## Migration Guide

Ambiguity sets have been removed.
2022-09-09 17:21:50 +00:00
Javier Goday
46f68161f7 #5817: derive_bundle macro is not hygienic (#5835)
# Objective
- Fixes #5817.
- Removes std::vec::Vec ambiguities in derive_bundle macro

## Solution
Prepend :: to standard library full Vec qualified type name (::std::vec::Vec)
2022-08-30 02:07:47 +00:00
ira
992681b59b Make Resource trait opt-in, requiring #[derive(Resource)] V2 (#5577)
*This PR description is an edited copy of #5007, written by @alice-i-cecile.*
# Objective
Follow-up to https://github.com/bevyengine/bevy/pull/2254. The `Resource` trait currently has a blanket implementation for all types that meet its bounds.

While ergonomic, this results in several drawbacks:

* it is possible to make confusing, silent mistakes such as inserting a function pointer (Foo) rather than a value (Foo::Bar) as a resource
* it is challenging to discover if a type is intended to be used as a resource
* we cannot later add customization options (see the [RFC](https://github.com/bevyengine/rfcs/blob/main/rfcs/27-derive-component.md) for the equivalent choice for Component).
* dependencies can use the same Rust type as a resource in invisibly conflicting ways
* raw Rust types used as resources cannot preserve privacy appropriately, as anyone able to access that type can read and write to internal values
* we cannot capture a definitive list of possible resources to display to users in an editor
## Notes to reviewers
 * Review this commit-by-commit; there's effectively no back-tracking and there's a lot of churn in some of these commits.
   *ira: My commits are not as well organized :')*
 * I've relaxed the bound on Local to Send + Sync + 'static: I don't think these concerns apply there, so this can keep things simple. Storing e.g. a u32 in a Local is fine, because there's a variable name attached explaining what it does.
 * I think this is a bad place for the Resource trait to live, but I've left it in place to make reviewing easier. IMO that's best tackled with https://github.com/bevyengine/bevy/issues/4981.

## Changelog
`Resource` is no longer automatically implemented for all matching types. Instead, use the new `#[derive(Resource)]` macro.

## Migration Guide
Add `#[derive(Resource)]` to all types you are using as a resource.

If you are using a third party type as a resource, wrap it in a tuple struct to bypass orphan rules. Consider deriving `Deref` and `DerefMut` to improve ergonomics.

`ClearColor` no longer implements `Component`. Using `ClearColor` as a component in 0.8 did nothing.
Use the `ClearColorConfig` in the `Camera3d` and `Camera2d` components instead.


Co-authored-by: Alice <alice.i.cecile@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: devil-ira <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-08-08 21:36:35 +00:00
JoJoJet
44e9cd4bfc Add attribute to ignore fields of derived labels (#5366)
# Objective

Fixes #5362 

## Solution

Add the attribute `#[label(ignore_fields)]` for `*Label` types.

```rust
#[derive(SystemLabel)]
pub enum MyLabel {
    One,

    // Previously this was not allowed since labels cannot contain data.
    #[system_label(ignore_fields)]
    Two(PhantomData<usize>),
}
```

## Notes

This label makes it possible for equality to behave differently depending on whether or not you are treating the type as a label. For example:

```rust
#[derive(SystemLabel, PartialEq, Eq)]
#[system_label(ignore_fields)]
pub struct Foo(usize);
```

If you compare it as a label, it will ignore the wrapped fields as the user requested. But if you compare it as a `Foo`, the derive will incorrectly compare the inner fields. I see a few solutions

1. Do nothing. This is technically intended behavior, but I think we should do our best to prevent footguns.
2. Generate impls of `PartialEq` and `Eq` along with the `#[derive(Label)]` macros. This is a breaking change as it requires all users to remove these derives from their types.
3. Only allow `PhantomData` to be used with `ignore_fields` -- seems needlessly prescriptive.

---

## Changelog

* Added the `ignore_fields` attribute to the derive macros for `*Label` types.
* Added an example showing off different forms of the derive macro.

<!--
## Migration Guide

> This section is optional. If there are no breaking changes, you can delete this section.

- If this PR is a breaking change (relative to the last release of Bevy), describe how a user might need to migrate their code to support these changes
- Simply adding new functionality is not a breaking change.
- Fixing behavior that was definitely a bug, rather than a questionable design choice is not a breaking change.
-->
2022-07-19 05:21:19 +00:00
Jakob Hellermann
d38a8dfdd7 add more SAFETY comments and lint for missing ones in bevy_ecs (#4835)
# Objective

`SAFETY` comments are meant to be placed before `unsafe` blocks and should contain the reasoning of why in this case the usage of unsafe is okay. This is useful when reading the code because it makes it clear which assumptions are required for safety, and makes it easier to spot possible unsoundness holes. It also forces the code writer to think of something to write and maybe look at the safety contracts of any called unsafe methods again to double-check their correct usage.

There's a clippy lint called `undocumented_unsafe_blocks` which warns when using a block without such a comment. 

## Solution

- since clippy expects `SAFETY` instead of `SAFE`, rename those
- add `SAFETY` comments in more places
- for the last remaining 3 places, add an `#[allow()]` and `// TODO` since I wasn't comfortable enough with the code to justify their safety
- add ` #![warn(clippy::undocumented_unsafe_blocks)]` to `bevy_ecs`


### Note for reviewers

The first commit only renames `SAFETY` to `SAFE` so it doesn't need a thorough review.
cb042a416e..55cef2d6fa is the diff for all other changes.

### Safety comments where I'm not too familiar with the code

774012ece5/crates/bevy_ecs/src/entity/mod.rs (L540-L546)

774012ece5/crates/bevy_ecs/src/world/entity_ref.rs (L249-L252)

### Locations left undocumented with a `TODO` comment

5dde944a30/crates/bevy_ecs/src/schedule/executor_parallel.rs (L196-L199)

5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L287-L289)

5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L413-L415)

Co-authored-by: Jakob Hellermann <hellermann@sipgate.de>
2022-07-04 14:44:24 +00:00
Daniel McNab
38a940dbbe Make derived SystemParam readonly if possible (#4650)
Required for https://github.com/bevyengine/bevy/pull/4402.

# Objective

- derived `SystemParam` implementations were never `ReadOnlySystemParamFetch`
- We want them to be, e.g. for `EventReader`

## Solution

- If possible, 'forward' the impl of `ReadOnlySystemParamFetch`.
2022-05-09 16:09:33 +00:00
Daniel McNab
ec805e9e07 Apply buffers in ParamSet (#4677)
# Objective

- Fix https://github.com/bevyengine/bevy/issues/4676

## Solution

- Fixes https://github.com/bevyengine/bevy/issues/4676
- I have no reason to think this isn't sound, but `ParamSet` is a bit spooky
2022-05-06 18:52:26 +00:00
James Liu
3e24b725af Pointerfication followup: Type safety and cleanup (#4621)
# Objective
The `Ptr` types gives free access to the underlying `NonNull<u8>`, which adds more publicly visible pointer wrangling than there needs to be. There are also a few edge cases where Ptr types could be more readily utilized for properly validating the soundness of ECS operations.

## Solution
 - Replace `*Ptr(Mut)::inner` with `cast` which requires a concrete type to give the pointer. This function could also have a `debug_assert` with an alignment check to ensure that the pointer is aligned properly, but is currently not included.
 - Use `OwningPtr::read` in ECS macros over casting the inner pointer around.
2022-05-03 20:07:58 +00:00
robtfm
b9f738da8d move system_param fetch struct into anonymous scope to avoid name collisions (#4100)
# Objective

avoid naming collisions with user structs when deriving ``system_param``.

## Solution

~rename the fetch struct created by ``#[derive(system_param)]`` from ``{}State`` to ``{}SysParamState``.~
place the fetch struct into an anonymous scope.

## Migration Guide

For code that was using a system param's fetch struct, such as ``EventReader``'s ``EventReaderState``, the fetch struct can now be identified via the SystemParam trait associated type ``Fetch``, e.g. for ``EventReader<T>`` it can be identified as ``<EventReader<'static, 'static, T> as SystemParam>::Fetch``
2022-05-02 18:26:50 +00:00
Yutao Yuan
2c145826a3 Fix type parameter name conflicts of derive(Bundle) (#4636)
# Objective

This code currently fails to compile with error ``the name `T` is already used for a generic parameter in this item's generic parameters``, because `T` is also used in code generated by `derive(Bundle)`.

```rust
#[derive(Bundle)]
struct MyBundle<T: Component> {
    component: T,
}
```

## Solution

Add double underscores to type parameter names in `derive(Bundle)`.
2022-05-02 11:58:51 +00:00
TheRawMeatball
73c78c3667 Use lifetimed, type erased pointers in bevy_ecs (#3001)
# Objective

`bevy_ecs` has large amounts of unsafe code which is hard to get right and makes it difficult to audit for soundness.

## Solution

Introduce lifetimed, type-erased pointers: `Ptr<'a>` `PtrMut<'a>` `OwningPtr<'a>'` and `ThinSlicePtr<'a, T>` which are newtypes around a raw pointer with a lifetime and conceptually representing strong invariants about the pointee and validity of the pointer.

The process of converting bevy_ecs to use these has already caught multiple cases of unsound behavior.

## Changelog

TL;DR for release notes: `bevy_ecs` now uses lifetimed, type-erased pointers internally, significantly improving safety and legibility without sacrificing performance. This should have approximately no end user impact, unless you were meddling with the (unfortunately public) internals of `bevy_ecs`.

- `Fetch`, `FilterFetch` and `ReadOnlyFetch` trait no longer have a `'state` lifetime
    - this was unneeded
- `ReadOnly/Fetch` associated types on `WorldQuery` are now on a new `WorldQueryGats<'world>` trait
    - was required to work around lack of Generic Associated Types (we wish to express `type Fetch<'a>: Fetch<'a>`)
- `derive(WorldQuery)` no longer requires `'w` lifetime on struct
    - this was unneeded, and improves the end user experience
- `EntityMut::get_unchecked_mut` returns `&'_ mut T` not `&'w mut T`
    - allows easier use of unsafe API with less footguns, and can be worked around via lifetime transmutery as a user
- `Bundle::from_components` now takes a `ctx` parameter to pass to the `FnMut` closure
    - required because closure return types can't borrow from captures
- `Fetch::init` takes `&'world World`, `Fetch::set_archetype` takes `&'world Archetype` and `&'world Tables`, `Fetch::set_table` takes `&'world Table`
    - allows types implementing `Fetch` to store borrows into world
- `WorldQuery` trait now has a `shrink` fn to shorten the lifetime in `Fetch::<'a>::Item`
    - this works around lack of subtyping of assoc types, rust doesnt allow you to turn `<T as Fetch<'static>>::Item'` into `<T as Fetch<'a>>::Item'`
    - `QueryCombinationsIter` requires this
- Most types implementing `Fetch` now have a lifetime `'w`
    - allows the fetches to store borrows of world data instead of using raw pointers

## Migration guide

- `EntityMut::get_unchecked_mut` returns a more restricted lifetime, there is no general way to migrate this as it depends on your code
- `Bundle::from_components` implementations must pass the `ctx` arg to `func`
- `Bundle::from_components` callers have to use a fn arg instead of closure captures for borrowing from world
- Remove lifetime args on `derive(WorldQuery)` structs as it is nonsensical
- `<Q as WorldQuery>::ReadOnly/Fetch` should be changed to either `RO/QueryFetch<'world>` or `<Q as WorldQueryGats<'world>>::ReadOnly/Fetch`
- `<F as Fetch<'w, 's>>` should be changed to `<F as Fetch<'w>>`
- Change the fn sigs of `Fetch::init/set_archetype/set_table` to match respective trait fn sigs
- Implement the required `fn shrink` on any `WorldQuery` implementations
- Move assoc types `Fetch` and `ReadOnlyFetch` on `WorldQuery` impls to `WorldQueryGats` impls
- Pass an appropriate `'world` lifetime to whatever fetch struct you are for some reason using

### Type inference regression

in some cases rustc may give spurrious errors when attempting to infer the `F` parameter on a query/querystate this can be fixed by manually specifying the type, i.e. `QueryState:🆕:<_, ()>(world)`. The error is rather confusing:

```rust=
error[E0271]: type mismatch resolving `<() as Fetch<'_>>::Item == bool`
    --> crates/bevy_pbr/src/render/light.rs:1413:30
     |
1413 |             main_view_query: QueryState::new(world),
     |                              ^^^^^^^^^^^^^^^ expected `bool`, found `()`
     |
     = note: required because of the requirements on the impl of `for<'x> FilterFetch<'x>` for `<() as WorldQueryGats<'x>>::Fetch`
note: required by a bound in `bevy_ecs::query::QueryState::<Q, F>::new`
    --> crates/bevy_ecs/src/query/state.rs:49:32
     |
49   |     for<'x> QueryFetch<'x, F>: FilterFetch<'x>,
     |                                ^^^^^^^^^^^^^^^ required by this bound in `bevy_ecs::query::QueryState::<Q, F>::new`
```

---

Made with help from @BoxyUwU and @alice-i-cecile 

Co-authored-by: Boxy <supbscripter@gmail.com>
2022-04-27 23:44:06 +00:00
TheRawMeatball
032b0f4bac Fix derive(SystemParam) macro (#4400)
Fixes the issue seen in #4398
2022-04-04 19:22:28 +00:00
bilsen
63fee2572b ParamSet for conflicting SystemParam:s (#2765)
# Objective
Add a system parameter `ParamSet` to be used as container for conflicting parameters.

## Solution
Added two methods to the SystemParamState trait, which gives the access used by the parameter. Did the implementation. Added some convenience methods to FilteredAccessSet. Changed `get_conflicts` to return every conflicting component instead of breaking on the first conflicting `FilteredAccess`.


Co-authored-by: bilsen <40690317+bilsen@users.noreply.github.com>
2022-03-29 23:39:38 +00:00
Daniel McNab
6e61fef67d Obviate the need for RunSystem, and remove it (#3817)
# Objective

- Fixes #3300
- `RunSystem` is messy

## Solution

- Adds the trick theorised in https://github.com/bevyengine/bevy/issues/3300#issuecomment-991791234

P.S. I also want this for an experimental refactoring of `Assets`, to remove the duplication of `Events<AssetEvent<T>>`


Co-authored-by: Carter Anderson <mcanders1@gmail.com>
2022-03-15 02:16:55 +00:00