# Objective
The `#[derive(WorldQuery)]` macro currently only supports structs with
named fields.
Same motivation as #6957. Remove sharp edges from the derive macro, make
it just work more often.
## Solution
Support tuple structs.
---
## Changelog
+ Added support for tuple structs to the `#[derive(WorldQuery)]` macro.
# Objective
While migrating the engine to use the `Tick` type in #7905, I forgot to
update `UnsafeWorldCell::increment_change_tick`.
## Solution
Update the function.
---
## Changelog
- The function `UnsafeWorldCell::increment_change_tick` is now
strongly-typed, returning a value of type `Tick` instead of a raw `u32`.
## Migration Guide
The function `UnsafeWorldCell::increment_change_tick` is now
strongly-typed, returning a value of type `Tick` instead of a raw `u32`.
# 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.
# Objective
The function `SyncUnsafeCell::from_mut` returns `&SyncUnsafeCell<T>`,
even though it could return `&mut SyncUnsafeCell<T>`. This means it is
not possible to call `get_mut` on the returned value, so you need to use
unsafe code to get exclusive access back.
## Solution
Return `&mut Self` instead of `&Self` in `SyncUnsafeCell::from_mut`.
This is consistent with my proposal for `UnsafeCell::from_mut`:
https://github.com/rust-lang/libs-team/issues/198.
Replace an unsafe pointer dereference with a safe call to `get_mut`.
---
## Changelog
+ The function `bevy_utils::SyncUnsafeCell::get_mut` now returns a value
of type `&mut SyncUnsafeCell<T>`. Previously, this returned an immutable
reference.
## Migration Guide
The function `bevy_utils::SyncUnsafeCell::get_mut` now returns a value
of type `&mut SyncUnsafeCell<T>`. Previously, this returned an immutable
reference.
# Objective
The documentation on `QueryState::for_each_unchecked` incorrectly says
that it can only be used with read-only queries.
## Solution
Remove the inaccurate sentence.
# 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())
}
}
```
# Objective
Our regression tests for `SystemParam` currently consist of a bunch of
loosely dispersed struct definitions. This is messy, and doesn't fully
test their functionality.
## Solution
Group the struct definitions into functions annotated with `#[test]`.
This not only makes the module more organized, but it allows us to call
`assert_is_system`, which has the potential to catch some bugs that
would have been missed with the old approach. Also, this approach is
consistent with how `WorldQuery` regression tests are organized.
# Objective
- Fixes#7659
## Solution
The idea of anonymous system sets or "implicit hidden organizational
sets" was briefly mentioned by @cart here:
https://github.com/bevyengine/bevy/pull/7634#issuecomment-1428619449.
- `Schedule::add_systems` creates an implicit, anonymous system set of
all systems in `SystemConfigs`.
- All dependencies and conditions from the `SystemConfigs` are now
applied to the implicit system set, instead of being applied to each
individual system. This should not change the behavior, AFAIU, because
`before`, `after`, `run_if` and `ambiguous_with` are transitive
properties from a set to its members.
- The newly added `AnonymousSystemSet` stores the names of its members
to provide better error messages.
- The names are stored in a reference counted slice, allowing fast
clones of the `AnonymousSystemSet`.
- However, only the pointer of the slice is used for hash and equality
operations
- This ensures that two `AnonymousSystemSet` are not equal, even if they
have the same members / member names.
- So two identical `add_systems` calls will produce two different
`AnonymousSystemSet`s.
- Clones of the same `AnonymousSystemSet` will be equal.
## Drawbacks
If my assumptions are correct, the observed behavior should stay the
same. But the number of system sets in the `Schedule` will increase with
each `add_systems` call. If this has negative performance implications,
`add_systems` could be changed to only create the implicit system set if
necessary / when a run condition was added.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
With the removal of base sets, some variants of `ScheduleBuildError` can
never occur and should be removed.
## Solution
- Remove the obsolete variants of `ScheduleBuildError`.
- Also fix a doc comment which mentioned base sets.
---
## Changelog
### Removed
- Remove `ScheduleBuildError::SystemInMultipleBaseSets` and
`ScheduleBuildError::SetInMultipleBaseSets`.
# 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.
# Objective
I ran into a case where I need to create a `CommandQueue` and push
standard `Command` actions like `Insert` or `Remove` to it manually. I
saw that `Remove` looked as follows:
```rust
struct Remove<T> {
entity: Entity,
phantom: PhantomData<T>
}
```
so naturally, I tried to use `Remove::<Foo>::from(entity)` but it didn't
exist. We need to specify the `PhantomData` explicitly when creating
this command action. The same goes for `RemoveResource` and
`InitResource`
## Solution
This PR implements the following:
- `From<Entity>` for `Remove<T>`
- `Default` for `RemoveResource` and `InitResource`
- use these traits in the implementation of methods of `Commands`
- rename `phantom` field on the structs above to `_phantom` to have a
more uniform field naming scheme for the command actions
---
## Changelog
> This section is optional. If this was a trivial fix, or has no
externally-visible impact, you can delete this section.
- Added: implemented `From<Entity>` for `Remove<T>` and `Default` for
`RemoveResource` and `InitResource` for ergonomics
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fix a bug with scene reload.
(This is a copy of #7570 but without the breaking API change, in order
to allow the bugfix to be introduced in 0.10.1)
When a scene was reloaded, it was corrupting components that weren't
native to the scene itself. In particular, when a DynamicScene was
created on Entity (A), all components in the scene without parents are
automatically added as children of Entity (A). But if that scene was
reloaded and the same ID of Entity (A) was a scene ID as well*, that
parent component was corrupted, causing the hierarchy to become
malformed and bevy to panic.
*For example, if Entity (A)'s ID was 3, and the scene contained an
entity with ID 3
This issue could affect any components that:
* Implemented `MapEntities`, basically components that contained
references to other entities
* Were added to entities from a scene file but weren't defined in the
scene file
- Fixes#7529
## Solution
The solution was to keep track of entities+components that had
`MapEntities` functionality during scene load, and only apply the entity
update behavior to them. They were tracked with a HashMap from the
component's TypeID to a vector of entity ID's. Then the
`ReflectMapEntities` struct was updated to hold a function that took a
list of entities to be applied to, instead of naively applying itself to
all values in the EntityMap.
(See this PR comment
https://github.com/bevyengine/bevy/pull/7570#issuecomment-1432302796 for
a story-based explanation of this bug and solution)
## Changelog
### Fixed
- Components that implement `MapEntities` added to scene entities after
load are not corrupted during scene reload.
# Objective
Documentation should no longer be using pre-stageless terminology to
avoid confusion.
## Solution
- update all docs referring to stages to instead refer to sets/schedules
where appropriate
- also mention `apply_system_buffers` for anything system-buffer-related
that previously referred to buffers being applied "at the end of a
stage"
# Objective
`Or<T>` should be a new type of `PhantomData<T>` instead of `T`.
## Solution
Make `Or<T>` a new type of `PhantomData<T>`.
## Migration Guide
`Or<T>` is just used as a type annotation and shouldn't be constructed.
# Objective
When using the `#[derive(WorldQuery)]` macro, the `ReadOnly` struct
generated has default (private) visibility for each field, regardless of
the visibility of the original field.
## Solution
For each field of a read-only `WorldQuery` variant, use the visibility
of the associated field defined on the original struct.
# Objective
Fix#1727Fix#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.
# Objective
The function `assert_is_system` is used in documentation tests to ensure
that example code actually produces valid systems. Currently,
`assert_is_system` just checks that each function parameter implements
`SystemParam`. To further check the validity of the system, we should
initialize the passed system so that it will be checked for conflicting
accesses. Not only does this enforce the validity of our examples, but
it provides a convenient way to demonstrate conflicting accesses via a
`should_panic` example, which is nicely rendered by rustdoc:
## Solution
Initialize the system with an empty world to trigger its internal access
conflict checks.
---
## Changelog
The function `bevy::ecs::system::assert_is_system` now panics when
passed a system with conflicting world accesses, as does
`assert_is_read_only_system`.
## Migration Guide
The functions `assert_is_system` and `assert_is_read_only_system` (in
`bevy_ecs::system`) now panic if the passed system has invalid world
accesses. Any tests that called this function on a system with invalid
accesses will now fail. Either fix the system's conflicting accesses, or
specify that the test is meant to fail:
1. For regular tests (that is, functions annotated with `#[test]`), add
the `#[should_panic]` attribute to the function.
2. For documentation tests, add `should_panic` to the start of the code
block: ` ```should_panic`
# Objective
We're currently using an unconditional `unwrap` in multiple locations
when inserting bundles into an entity when we know it will never fail.
This adds a large amount of extra branching that could be avoided on in
release builds.
## Solution
Use `DebugCheckedUnwrap` in bundle insertion code where relevant. Add
and update the safety comments to match.
This should remove the panicking branches from release builds, which has
a significant impact on the generated code:
https://github.com/james7132/bevy_asm_tests/compare/less-panicking-bundles#diff-e55a27cfb1615846ed3b6472f15a1aed66ed394d3d0739b3117f95cf90f46951R2086
shows about a 10% reduction in the number of generated instructions for
`EntityMut::insert`, `EntityMut::remove`, `EntityMut::take`, and related
functions.
---------
Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
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`
# Objective
#7863 introduced a potential footgun. When trying to incorrectly add a user-defined type using `in_base_set`, the compiler will suggest that the user implement `BaseSystemSet` for their type. This is a reasonable-sounding suggestion, however this is not the correct way to make a base set, and will lead to a confusing panic message when a marker trait is implemented for the wrong type.
## Solution
Rewrite the documentation for these traits, making it more clear that `BaseSystemSet` is a marker for types that are already base sets, and not a way to define a base set.
# Objective
The trait `IntoSystemConfig<>` requires each implementer to repeat every single member method, even though they can all be implemented by just deferring to `SystemConfig`.
## Solution
Add default implementations to most member methods.
