# Objective
- Currently adding observers spawns an entity which implicitly flushes
the command queue, which can cause undefined behaviour if the
`WorldEntityMut` is used after this
- The reason `WorldEntityMut` attempted to (unsuccessfully) avoid
flushing commands until finished was that such commands may move or
despawn the entity being referenced, invalidating the cached location.
- With the introduction of hooks and observers, this isn't sensible
anymore as running the commands generated by hooks immediately is
required to maintain correct ordering of operations and to not expose
the world in an inconsistent state
- Objective is to make command flushing deterministic and fix the
related issues
- Fixes#16212
- Fixes#14621
- Fixes#16034
## Solution
- Allow `WorldEntityMut` to exist even when it refers to a despawned
entity by allowing `EntityLocation` to be marked invalid
- Add checks to all methods to panic if trying to access a despawned
entity
- Flush command queue after every operation that might trigger hooks or
observers
- Update entity location always after flushing command queue
## Testing
- Added test cases for currently broken behaviour
- Added test cases that flushes happen in all operations
- Added test cases to ensure hooks and commands are run exactly in
correct order when nested
---
Todo:
- [x] Write migration guide
- [x] Add tests that using `EntityWorldMut` on a despawned entity panics
- [x] Add tests that commands are flushed after every operation that is
supposed to flush them
- [x] Add tests that hooks, observers and their spawned commands are run
in the correct order when nested
---
## Migration Guide
Previously `EntityWorldMut` triggered command queue flushes in
unpredictable places, which could interfere with hooks and observers.
Now the command queue is flushed always immediately after any call in
`EntityWorldMut` that spawns or despawns an entity, or adds, removes or
replaces a component. This means hooks and observers will run their
commands in the correct order.
As a side effect, there is a possibility that a hook or observer could
despawn the entity that is being referred to by `EntityWorldMut`. This
could already currently happen if an observer was added while keeping an
`EntityWorldMut` referece and would cause unsound behaviour. If the
entity has been despawned, calling any methods which require the entity
location will panic. This matches the behaviour that `Commands` will
panic if called on an already despawned entity. In the extremely rare
case where taking a new `EntityWorldMut` reference or otherwise
restructuring the code so that this case does not happen is not
possible, there's a new `is_despawned` method that can be used to check
if the referred entity has been despawned.
# Objective
- Fixes#16208
## Solution
- Added an associated type to `Component`, `Mutability`, which flags
whether a component is mutable, or immutable. If `Mutability= Mutable`,
the component is mutable. If `Mutability= Immutable`, the component is
immutable.
- Updated `derive_component` to default to mutable unless an
`#[component(immutable)]` attribute is added.
- Updated `ReflectComponent` to check if a component is mutable and, if
not, panic when attempting to mutate.
## Testing
- CI
- `immutable_components` example.
---
## Showcase
Users can now mark a component as `#[component(immutable)]` to prevent
safe mutation of a component while it is attached to an entity:
```rust
#[derive(Component)]
#[component(immutable)]
struct Foo {
// ...
}
```
This prevents creating an exclusive reference to the component while it
is attached to an entity. This is particularly powerful when combined
with component hooks, as you can now fully track a component's value,
ensuring whatever invariants you desire are upheld. Before this would be
done my making a component private, and manually creating a `QueryData`
implementation which only permitted read access.
<details>
<summary>Using immutable components as an index</summary>
```rust
/// This is an example of a component like [`Name`](bevy::prelude::Name), but immutable.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Component)]
#[component(
immutable,
on_insert = on_insert_name,
on_replace = on_replace_name,
)]
pub struct Name(pub &'static str);
/// This index allows for O(1) lookups of an [`Entity`] by its [`Name`].
#[derive(Resource, Default)]
struct NameIndex {
name_to_entity: HashMap<Name, Entity>,
}
impl NameIndex {
fn get_entity(&self, name: &'static str) -> Option<Entity> {
self.name_to_entity.get(&Name(name)).copied()
}
}
fn on_insert_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) {
let Some(&name) = world.entity(entity).get::<Name>() else {
unreachable!()
};
let Some(mut index) = world.get_resource_mut::<NameIndex>() else {
return;
};
index.name_to_entity.insert(name, entity);
}
fn on_replace_name(mut world: DeferredWorld<'_>, entity: Entity, _component: ComponentId) {
let Some(&name) = world.entity(entity).get::<Name>() else {
unreachable!()
};
let Some(mut index) = world.get_resource_mut::<NameIndex>() else {
return;
};
index.name_to_entity.remove(&name);
}
// Setup our name index
world.init_resource::<NameIndex>();
// Spawn some entities!
let alyssa = world.spawn(Name("Alyssa")).id();
let javier = world.spawn(Name("Javier")).id();
// Check our index
let index = world.resource::<NameIndex>();
assert_eq!(index.get_entity("Alyssa"), Some(alyssa));
assert_eq!(index.get_entity("Javier"), Some(javier));
// Changing the name of an entity is also fully capture by our index
world.entity_mut(javier).insert(Name("Steven"));
// Javier changed their name to Steven
let steven = javier;
// Check our index
let index = world.resource::<NameIndex>();
assert_eq!(index.get_entity("Javier"), None);
assert_eq!(index.get_entity("Steven"), Some(steven));
```
</details>
Additionally, users can use `Component<Mutability = ...>` in trait
bounds to enforce that a component _is_ mutable or _is_ immutable. When
using `Component` as a trait bound without specifying `Mutability`, any
component is applicable. However, methods which only work on mutable or
immutable components are unavailable, since the compiler must be
pessimistic about the type.
## Migration Guide
- When implementing `Component` manually, you must now provide a type
for `Mutability`. The type `Mutable` provides equivalent behaviour to
earlier versions of `Component`:
```rust
impl Component for Foo {
type Mutability = Mutable;
// ...
}
```
- When working with generic components, you may need to specify that
your generic parameter implements `Component<Mutability = Mutable>`
rather than `Component` if you require mutable access to said component.
- The entity entry API has had to have some changes made to minimise
friction when working with immutable components. Methods which
previously returned a `Mut<T>` will now typically return an
`OccupiedEntry<T>` instead, requiring you to add an `into_mut()` to get
the `Mut<T>` item again.
## Draft Release Notes
Components can now be made immutable while stored within the ECS.
Components are the fundamental unit of data within an ECS, and Bevy
provides a number of ways to work with them that align with Rust's rules
around ownership and borrowing. One part of this is hooks, which allow
for defining custom behavior at key points in a component's lifecycle,
such as addition and removal. However, there is currently no way to
respond to _mutation_ of a component using hooks. The reasons for this
are quite technical, but to summarize, their addition poses a
significant challenge to Bevy's core promises around performance.
Without mutation hooks, it's relatively trivial to modify a component in
such a way that breaks invariants it intends to uphold. For example, you
can use `core::mem::swap` to swap the components of two entities,
bypassing the insertion and removal hooks.
This means the only way to react to this modification is via change
detection in a system, which then begs the question of what happens
_between_ that alteration and the next run of that system?
Alternatively, you could make your component private to prevent
mutation, but now you need to provide commands and a custom `QueryData`
implementation to allow users to interact with your component at all.
Immutable components solve this problem by preventing the creation of an
exclusive reference to the component entirely. Without an exclusive
reference, the only way to modify an immutable component is via removal
or replacement, which is fully captured by component hooks. To make a
component immutable, simply add `#[component(immutable)]`:
```rust
#[derive(Component)]
#[component(immutable)]
struct Foo {
// ...
}
```
When implementing `Component` manually, there is an associated type
`Mutability` which controls this behavior:
```rust
impl Component for Foo {
type Mutability = Mutable;
// ...
}
```
Note that this means when working with generic components, you may need
to specify that a component is mutable to gain access to certain
methods:
```rust
// Before
fn bar<C: Component>() {
// ...
}
// After
fn bar<C: Component<Mutability = Mutable>>() {
// ...
}
```
With this new tool, creating index components, or caching data on an
entity should be more user friendly, allowing libraries to provide APIs
relying on components and hooks to uphold their invariants.
## Notes
- ~~I've done my best to implement this feature, but I'm not happy with
how reflection has turned out. If any reflection SMEs know a way to
improve this situation I'd greatly appreciate it.~~ There is an
outstanding issue around the fallibility of mutable methods on
`ReflectComponent`, but the DX is largely unchanged from `main` now.
- I've attempted to prevent all safe mutable access to a component that
does not implement `Component<Mutability = Mutable>`, but there may
still be some methods I have missed. Please indicate so and I will
address them, as they are bugs.
- Unsafe is an escape hatch I am _not_ attempting to prevent. Whatever
you do with unsafe is between you and your compiler.
- I am marking this PR as ready, but I suspect it will undergo fairly
major revisions based on SME feedback.
- I've marked this PR as _Uncontroversial_ based on the feature, not the
implementation.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Benjamin Brienen <benjamin.brienen@outlook.com>
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
Co-authored-by: Nuutti Kotivuori <naked@iki.fi>
## Objective
Fixes#1515
This PR implements a flexible entity cloning system. The primary use
case for it is to clone dynamically-generated entities.
Example:
```rs
#[derive(Component, Clone)]
pub struct Projectile;
#[derive(Component, Clone)]
pub struct Damage {
value: f32,
}
fn player_input(
mut commands: Commands,
projectiles: Query<Entity, With<Projectile>>,
input: Res<ButtonInput<KeyCode>>,
) {
// Fire a projectile
if input.just_pressed(KeyCode::KeyF) {
commands.spawn((Projectile, Damage { value: 10.0 }));
}
// Triplicate all active projectiles
if input.just_pressed(KeyCode::KeyT) {
for projectile in projectiles.iter() {
// To triplicate a projectile we need to create 2 more clones
for _ in 0..2{
commands.clone_entity(projectile)
}
}
}
}
```
## Solution
### Commands
Add a `clone_entity` command to create a clone of an entity with all
components that can be cloned. Components that can't be cloned will be
ignored.
```rs
commands.clone_entity(entity)
```
If there is a need to configure the cloning process (like set to clone
recursively), there is a second command:
```rs
commands.clone_entity_with(entity, |builder| {
builder.recursive(true)
});
```
Both of these commands return `EntityCommands` of the cloned entity, so
the copy can be modified afterwards.
### Builder
All these commands use `EntityCloneBuilder` internally. If there is a
need to clone an entity using `World` instead, it is also possible:
```rs
let entity = world.spawn(Component).id();
let entity_clone = world.spawn_empty().id();
EntityCloneBuilder::new(&mut world).clone_entity(entity, entity_clone);
```
Builder has methods to `allow` or `deny` certain components during
cloning if required and can be extended by implementing traits on it.
This PR includes two `EntityCloneBuilder` extensions:
`CloneEntityWithObserversExt` to configure adding cloned entity to
observers of the original entity, and `CloneEntityRecursiveExt` to
configure cloning an entity recursively.
### Clone implementations
By default, all components that implement either `Clone` or `Reflect`
will be cloned (with `Clone`-based implementation preferred in case
component implements both).
This can be overriden on a per-component basis:
```rs
impl Component for SomeComponent {
const STORAGE_TYPE: StorageType = StorageType::Table;
fn get_component_clone_handler() -> ComponentCloneHandler {
// Don't clone this component
ComponentCloneHandler::Ignore
}
}
```
### `ComponentCloneHandlers`
Clone implementation specified in `get_component_clone_handler` will get
registered in `ComponentCloneHandlers` (stored in
`bevy_ecs::component::Components`) at component registration time.
The clone handler implementation provided by a component can be
overriden after registration like so:
```rs
let component_id = world.components().component_id::<Component>().unwrap()
world.get_component_clone_handlers_mut()
.set_component_handler(component_id, ComponentCloneHandler::Custom(component_clone_custom))
```
The default clone handler for all components that do not explicitly
define one (or don't derive `Component`) is
`component_clone_via_reflect` if `bevy_reflect` feature is enabled, and
`component_clone_ignore` (noop) otherwise.
Default handler can be overriden using
`ComponentCloneHandlers::set_default_handler`
### Handlers
Component clone handlers can be used to modify component cloning
behavior. The general signature for a handler that can be used in
`ComponentCloneHandler::Custom` is as follows:
```rs
pub fn component_clone_custom(
world: &mut DeferredWorld,
entity_cloner: &EntityCloner,
) {
// implementation
}
```
The `EntityCloner` implementation (used internally by
`EntityCloneBuilder`) assumes that after calling this custom handler,
the `target` entity has the desired version of the component from the
`source` entity.
### Builder handler overrides
Besides component-defined and world-overriden handlers,
`EntityCloneBuilder` also has a way to override handlers locally. It is
mainly used to allow configuration methods like `recursive` and
`add_observers`.
```rs
// From observer clone handler implementation
impl CloneEntityWithObserversExt for EntityCloneBuilder<'_> {
fn add_observers(&mut self, add_observers: bool) -> &mut Self {
if add_observers {
self.override_component_clone_handler::<ObservedBy>(ComponentCloneHandler::Custom(
component_clone_observed_by,
))
} else {
self.remove_component_clone_handler_override::<ObservedBy>()
}
}
}
```
## Testing
Includes some basic functionality tests and doctests.
Performance-wise this feature is the same as calling `clone` followed by
`insert` for every entity component. There is also some inherent
overhead due to every component clone handler having to access component
data through `World`, but this can be reduced without breaking current
public API in a later PR.
# Objective
There is currently no way of getting `QueryState` from `&World`, so it
is hard to, for example, iterate over all entities with a component,
only having `&World`.
## Solution
Add `try_new` function to `QueryState` that internally uses
`WorldQuery`'s `get_state`.
## Testing
No testing
# Objective
- Fixes#16406 even more. The previous implementation did not take into
account the depth of the requiree when setting the depth relative to the
required_by component.
## Solution
- Add the depth of the requiree!
## Testing
- Added a test.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Seemed to have missed the export of `DynamicComponentFetch` from #15593.
`TryFromFilteredError` which is returned by `impl
TryFrom<FiliteredEntityMut/Ref> for EntityRef/Mut` also seemed to have
been missing.
## Solution
Export both of them.
# Objective
- Fixes: #15603
## Solution
- Add an unsafe `get_mut_by_id_unchecked` to `EntityMut` that borrows
&self instead of &mut self, thereby allowing access to multiple
components simultaneously.
## Testing
- a unit test function `get_mut_by_id_unchecked` was added.
---------
Co-authored-by: Mike <mike.hsu@gmail.com>
# Objective
Re-enable some tests in `entity_ref.rs` that are marked as `#[ignore]`,
but that pass after #14561.
## Solution
Remove `#[ignore]` from those tests.
# Objective
Bevy seems to want to standardize on "American English" spellings. Not
sure if this is laid out anywhere in writing, but see also #15947.
While perusing the docs for `typos`, I noticed that it has a `locale`
config option and tried it out.
## Solution
Switch to `en-us` locale in the `typos` config and run `typos -w`
## Migration Guide
The following methods or fields have been renamed from `*dependants*` to
`*dependents*`.
- `ProcessorAssetInfo::dependants`
- `ProcessorAssetInfos::add_dependant`
- `ProcessorAssetInfos::non_existent_dependants`
- `AssetInfo::dependants_waiting_on_load`
- `AssetInfo::dependants_waiting_on_recursive_dep_load`
- `AssetInfos::loader_dependants`
- `AssetInfos::remove_dependants_and_labels`
# Objective
- Closes#14774
## Solution
Added:
```rust
impl<'w, E, B: Bundle> Trigger<'w, E, B> {
pub fn components(&self) -> &[ComponentId];
}
```
I went with storing it in the trigger as a `SmallVec<[Component; 1]>`
because a singular target component will be the most common case, and it
remains the same size as `Vec<ComponentId>`.
## Testing
Added a test.
# Objective
Another clippy-lint fix: the goal is so that `ci lints` actually
displays the problems that a contributor caused, and not a bunch of
existing stuff in the repo. (when run on nightly)
## Solution
This fixes all but the `clippy::needless_lifetimes` lint, which will
result in substantially more fixes and be in other PR(s). I also
explicitly allow `non_local_definitions` since it is [not working
correctly, but will be
fixed](https://github.com/rust-lang/rust/issues/131643).
A few things were manually fixed: for example, some places had an
explicitly defined `div_ceil` function that was used, which is no longer
needed since this function is stable on unsigned integers. Also, empty
lines in doc comments were handled individually.
## Testing
I ran `cargo clippy --workspace --all-targets --all-features --fix
--allow-staged` with the `clippy::needless_lifetimes` lint marked as
`allow` in `Cargo.toml` to avoid fixing that too. It now passes with all
but the listed lint.
# Objective
`insert_or_spawn_batch` exists, but a version for just inserting doesn't
- Closes#2693
- Closes#8384
- Adopts/supersedes #8600
## Solution
Add `insert_batch`, along with the most common `insert` variations:
- `World::insert_batch`
- `World::insert_batch_if_new`
- `World::try_insert_batch`
- `World::try_insert_batch_if_new`
- `Commands::insert_batch`
- `Commands::insert_batch_if_new`
- `Commands::try_insert_batch`
- `Commands::try_insert_batch_if_new`
## Testing
Added tests, and added a benchmark for `insert_batch`.
Performance is slightly better than `insert_or_spawn_batch` when only
inserting:
<details>
<summary>old benchmark</summary>
This was before reworking it to remove the `UnsafeWorldCell`:
</details>
---
## Showcase
Usage is the same as `insert_or_spawn_batch`:
```
use bevy_ecs::{entity::Entity, world::World, component::Component};
#[derive(Component)]
struct A(&'static str);
#[derive(Component, PartialEq, Debug)]
struct B(f32);
let mut world = World::new();
let entity_a = world.spawn_empty().id();
let entity_b = world.spawn_empty().id();
world.insert_batch([
(entity_a, (A("a"), B(0.0))),
(entity_b, (A("b"), B(1.0))),
]);
assert_eq!(world.get::<B>(entity_a), Some(&B(0.0)));
```
# Objective
If a `Resource` implements `FromWorld` or `Default`, it's nicer to be
able to write:
```rust
let foo = world.get_resource_or_init::<Foo>();
```
Rather than:
```rust
let foo = world.get_resource_or_insert_with(Foo::default);
```
The latter is also not possible if a type implements `FromWorld` only,
and not `Default`.
## Solution
Added:
```rust
impl World {
pub fn get_resource_or_init<R: Resource + FromWorld>(&mut self) -> Mut<'_, R>;
}
```
Turns out all current in-engine uses of `get_resource_or_insert_with`
are exactly the above, so they've also been replaced.
## Testing
- Added a doc-test.
- Also added a doc-test for `World::get_resource_or_insert_with`.
# Objective
- Closes#15752
Calling the functions `App::observe` and `World::observe` doesn't make
sense because you're not "observing" the `App` or `World`, you're adding
an observer that listens for an event that occurs *within* the `World`.
We should rename them to better fit this.
## Solution
Renames:
- `App::observe` -> `App::add_observer`
- `World::observe` -> `World::add_observer`
- `Commands::observe` -> `Commands::add_observer`
- `EntityWorldMut::observe_entity` -> `EntityWorldMut::observe`
(Note this isn't a breaking change as the original rename was introduced
earlier this cycle.)
## Testing
Reusing current tests.
# Objective
After merging retained rendering world #15320, we now have a good way of
creating a link between worlds (*HIYAA intensifies*). This means that
`get_or_spawn` is no longer necessary for that function. Entity should
be opaque as the warning above `get_or_spawn` says. This is also part of
#15459.
I'm deprecating `get_or_spawn_batch` in a different PR in order to keep
the PR small in size.
## Solution
Deprecate `get_or_spawn` and replace it with `get_entity` in most
contexts. If it's possible to query `&RenderEntity`, then the entity is
synced and `render_entity.id()` is initialized in the render world.
## Migration Guide
If you are given an `Entity` and you want to do something with it, use
`Commands.entity(...)` or `World.entity(...)`. If instead you want to
spawn something use `Commands.spawn(...)` or `World.spawn(...)`. If you
are not sure if an entity exists, you can always use `get_entity` and
match on the `Option<...>` that is returned.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Following the pattern established in #15593, we can reduce the API
surface of `World` by providing a single function to grab both a
singular entity reference, or multiple entity references.
## Solution
The following functions can now also take multiple entity IDs and will
return multiple entity references back:
- `World::entity`
- `World::get_entity`
- `World::entity_mut`
- `World::get_entity_mut`
- `DeferredWorld::entity_mut`
- `DeferredWorld::get_entity_mut`
If you pass in X, you receive Y:
- give a single `Entity`, receive a single `EntityRef`/`EntityWorldMut`
(matches current behavior)
- give a `[Entity; N]`/`&[Entity; N]` (array), receive an equally-sized
`[EntityRef; N]`/`[EntityMut; N]`
- give a `&[Entity]` (slice), receive a
`Vec<EntityRef>`/`Vec<EntityMut>`
- give a `&EntityHashSet`, receive a
`EntityHashMap<EntityRef>`/`EntityHashMap<EntityMut>`
Note that `EntityWorldMut` is only returned in the single-entity case,
because having multiple at the same time would lead to UB. Also,
`DeferredWorld` receives an `EntityMut` in the single-entity case
because it does not allow structural access.
## Testing
- Added doc-tests on `World::entity`, `World::entity_mut`, and
`DeferredWorld::entity_mut`
- Added tests for aliased mutability and entity existence
---
## Showcase
<details>
<summary>Click to view showcase</summary>
The APIs for fetching `EntityRef`s and `EntityMut`s from the `World`
have been unified.
```rust
// This code will be referred to by subsequent code blocks.
let world = World::new();
let e1 = world.spawn_empty().id();
let e2 = world.spawn_empty().id();
let e3 = world.spawn_empty().id();
```
Querying for a single entity remains mostly the same:
```rust
// 0.14
let eref: EntityRef = world.entity(e1);
let emut: EntityWorldMut = world.entity_mut(e1);
let eref: Option<EntityRef> = world.get_entity(e1);
let emut: Option<EntityWorldMut> = world.get_entity_mut(e1);
// 0.15
let eref: EntityRef = world.entity(e1);
let emut: EntityWorldMut = world.entity_mut(e1);
let eref: Result<EntityRef, Entity> = world.get_entity(e1);
let emut: Result<EntityWorldMut, Entity> = world.get_entity_mut(e1);
```
Querying for multiple entities with an array has changed:
```rust
// 0.14
let erefs: [EntityRef; 2] = world.many_entities([e1, e2]);
let emuts: [EntityMut; 2] = world.many_entities_mut([e1, e2]);
let erefs: Result<[EntityRef; 2], Entity> = world.get_many_entities([e1, e2]);
let emuts: Result<[EntityMut; 2], QueryEntityError> = world.get_many_entities_mut([e1, e2]);
// 0.15
let erefs: [EntityRef; 2] = world.entity([e1, e2]);
let emuts: [EntityMut; 2] = world.entity_mut([e1, e2]);
let erefs: Result<[EntityRef; 2], Entity> = world.get_entity([e1, e2]);
let emuts: Result<[EntityMut; 2], EntityFetchError> = world.get_entity_mut([e1, e2]);
```
Querying for multiple entities with a slice has changed:
```rust
let ids = vec![e1, e2, e3]);
// 0.14
let erefs: Result<Vec<EntityRef>, Entity> = world.get_many_entities_dynamic(&ids[..]);
let emuts: Result<Vec<EntityMut>, QueryEntityError> = world.get_many_entities_dynamic_mut(&ids[..]);
// 0.15
let erefs: Result<Vec<EntityRef>, Entity> = world.get_entity(&ids[..]);
let emuts: Result<Vec<EntityMut>, EntityFetchError> = world.get_entity_mut(&ids[..]);
let erefs: Vec<EntityRef> = world.entity(&ids[..]); // Newly possible!
let emuts: Vec<EntityMut> = world.entity_mut(&ids[..]); // Newly possible!
```
Querying for multiple entities with an `EntityHashSet` has changed:
```rust
let set = EntityHashSet::from_iter([e1, e2, e3]);
// 0.14
let emuts: Result<Vec<EntityMut>, QueryEntityError> = world.get_many_entities_from_set_mut(&set);
// 0.15
let emuts: Result<EntityHashMap<EntityMut>, EntityFetchError> = world.get_entity_mut(&set);
let erefs: Result<EntityHashMap<EntityRef>, EntityFetchError> = world.get_entity(&set); // Newly possible!
let emuts: EntityHashMap<EntityMut> = world.entity_mut(&set); // Newly possible!
let erefs: EntityHashMap<EntityRef> = world.entity(&set); // Newly possible!
```
</details>
## Migration Guide
- `World::get_entity` now returns `Result<_, Entity>` instead of
`Option<_>`.
- Use `world.get_entity(..).ok()` to return to the previous behavior.
- `World::get_entity_mut` and `DeferredWorld::get_entity_mut` now return
`Result<_, EntityFetchError>` instead of `Option<_>`.
- Use `world.get_entity_mut(..).ok()` to return to the previous
behavior.
- Type inference for `World::entity`, `World::entity_mut`,
`World::get_entity`, `World::get_entity_mut`,
`DeferredWorld::entity_mut`, and `DeferredWorld::get_entity_mut` has
changed, and might now require the input argument's type to be
explicitly written when inside closures.
- The following functions have been deprecated, and should be replaced
as such:
- `World::many_entities` -> `World::entity::<[Entity; N]>`
- `World::many_entities_mut` -> `World::entity_mut::<[Entity; N]>`
- `World::get_many_entities` -> `World::get_entity::<[Entity; N]>`
- `World::get_many_entities_dynamic` -> `World::get_entity::<&[Entity]>`
- `World::get_many_entities_mut` -> `World::get_entity_mut::<[Entity;
N]>`
- The equivalent return type has changed from `Result<_,
QueryEntityError>` to `Result<_, EntityFetchError>`
- `World::get_many_entities_dynamic_mut` ->
`World::get_entity_mut::<&[Entity]>1
- The equivalent return type has changed from `Result<_,
QueryEntityError>` to `Result<_, EntityFetchError>`
- `World::get_many_entities_from_set_mut` ->
`World::get_entity_mut::<&EntityHashSet>`
- The equivalent return type has changed from `Result<Vec<EntityMut>,
QueryEntityError>` to `Result<EntityHashMap<EntityMut>,
EntityFetchError>`. If necessary, you can still convert the
`EntityHashMap` into a `Vec`.
## Objective
The new Required Components feature (#14791) in Bevy allows spawning a
fixed set of components with a single method with cool require macro.
However, there's currently no corresponding method to remove all those
components together. This makes it challenging to keep insertion and
removal code in sync, especially for simple using cases.
```rust
#[derive(Component)]
#[require(Y)]
struct X;
#[derive(Component, Default)]
struct Y;
world.entity_mut(e).insert(X); // Spawns both X and Y
world.entity_mut(e).remove::<X>();
world.entity_mut(e).remove::<Y>(); // We need to manually remove dependencies without any sync with the `require` macro
```
## Solution
Simplifies component management by providing operations for removal
required components.
This PR introduces simple 'footgun' methods to removes all components of
this bundle and its required components.
Two new methods are introduced:
For Commands:
```rust
commands.entity(e).remove_with_requires::<B>();
```
For World:
```rust
world.entity_mut(e).remove_with_requires::<B>();
```
For performance I created new field in Bundels struct. This new field
"contributed_bundle_ids" contains cached ids for dynamic bundles
constructed from bundle_info.cintributed_components()
## Testing
The PR includes three test cases:
1. Removing a single component with requirements using World.
2. Removing a bundle with requirements using World.
3. Removing a single component with requirements using Commands.
4. Removing a single component with **runtime** requirements using
Commands
These tests ensure the feature works as expected across different
scenarios.
## Showcase
Example:
```rust
use bevy_ecs::prelude::*;
#[derive(Component)]
#[require(Y)]
struct X;
#[derive(Component, Default)]
#[require(Z)]
struct Y;
#[derive(Component, Default)]
struct Z;
#[derive(Component)]
struct W;
let mut world = World::new();
// Spawn an entity with X, Y, Z, and W components
let entity = world.spawn((X, W)).id();
assert!(world.entity(entity).contains::<X>());
assert!(world.entity(entity).contains::<Y>());
assert!(world.entity(entity).contains::<Z>());
assert!(world.entity(entity).contains::<W>());
// Remove X and required components Y, Z
world.entity_mut(entity).remove_with_requires::<X>();
assert!(!world.entity(entity).contains::<X>());
assert!(!world.entity(entity).contains::<Y>());
assert!(!world.entity(entity).contains::<Z>());
assert!(world.entity(entity).contains::<W>());
```
## Motivation for PR
#15580
## Performance
I made simple benchmark
```rust
let mut world = World::default();
let entity = world.spawn_empty().id();
let steps = 100_000_000;
let start = std::time::Instant::now();
for _ in 0..steps {
world.entity_mut(entity).insert(X);
world.entity_mut(entity).remove::<(X, Y, Z, W)>();
}
let end = std::time::Instant::now();
println!("normal remove: {:?} ", (end - start).as_secs_f32());
println!("one remove: {:?} micros", (end - start).as_secs_f64() / steps as f64 * 1_000_000.0);
let start = std::time::Instant::now();
for _ in 0..steps {
world.entity_mut(entity).insert(X);
world.entity_mut(entity).remove_with_requires::<X>();
}
let end = std::time::Instant::now();
println!("remove_with_requires: {:?} ", (end - start).as_secs_f32());
println!("one remove_with_requires: {:?} micros", (end - start).as_secs_f64() / steps as f64 * 1_000_000.0);
```
Output:
CPU: Amd Ryzen 7 2700x
```bash
normal remove: 17.36135
one remove: 0.17361348299999999 micros
remove_with_requires: 17.534006
one remove_with_requires: 0.17534005400000002 micros
```
NOTE: I didn't find any tests or mechanism in the repository to update
BundleInfo after creating new runtime requirements with an existing
BundleInfo. So this PR also does not contain such logic.
## Future work (outside this PR)
Create cache system for fast removing components in "safe" mode, where
"safe" mode is remove only required components that will be no longer
required after removing root component.
---------
Co-authored-by: a.yamaev <a.yamaev@smartengines.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Support accessing dynamic resources in a dynamic system, including
accessing them by component id. This is similar to how dynamic
components can be queried using `Query<FilteredEntityMut>`.
## Solution
Create `FilteredResources` and `FilteredResourcesMut` types that act
similar to `FilteredEntityRef` and `FilteredEntityMut` and that can be
used as system parameters.
## Example
```rust
// Use `FilteredResourcesParamBuilder` to declare access to resources.
let system = (FilteredResourcesParamBuilder::new(|builder| {
builder.add_read::<B>().add_read::<C>();
}),)
.build_state(&mut world)
.build_system(resource_system);
world.init_resource::<A>();
world.init_resource::<C>();
fn resource_system(res: FilteredResources) {
// The resource exists, but we have no access, so we can't read it.
assert!(res.get::<A>().is_none());
// The resource doesn't exist, so we can't read it.
assert!(res.get::<B>().is_none());
// The resource exists and we have access, so we can read it.
let c = res.get::<C>().unwrap();
// The type parameter can be left out if it can be determined from use.
let c: Res<C> = res.get().unwrap();
}
```
## Future Work
As a follow-up PR, `ReflectResource` can be modified to take `impl
Into<FilteredResources>`, similar to how `ReflectComponent` takes `impl
Into<FilteredEntityRef>`. That will allow dynamic resources to be
accessed using reflection.
# Objective
The current observers have some unfortunate footguns where you can end
up confused about what is actually being observed. For apps you can
chain observe like `app.observe(..).observe(..)` which works like you
would expect, but if you try the same with world the first `observe()`
will return the `EntityWorldMut` for the created observer, and the
second `observe()` will only observe on the observer entity. It took
several hours for multiple people on discord to figure this out, which
is not a great experience.
## Solution
Rename `observe` on entities to `observe_entity`. It's slightly more
verbose when you know you have an entity, but it feels right to me that
observers for specific things have more specific naming, and it prevents
this issue completely.
Another possible solution would be to unify `observe` on `App` and
`World` to have the same kind of return type, but I'm not sure exactly
what that would look like.
## Testing
Simple name change, so only concern is docs really.
---
## Migration Guide
The `observe()` method on entities has been renamed to
`observe_entity()` to prevent confusion about what is being observed in
some cases.
# Objective
Fixes#14511.
`despawn` allows you to remove entities from the world. However, if the
entity does not exist, it emits a warning. This may not be intended
behavior for many users who have use cases where they need to call
`despawn` regardless of if the entity actually exists (see the issue),
or don't care in general if the entity already doesn't exist.
(Also trying to gauge interest on if this feature makes sense, I'd
personally love to have it, but I could see arguments that this might be
a footgun. Just trying to help here 😄 If there's no contention I could
also implement this for `despawn_recursive` and `despawn_descendants` in
the same PR)
## Solution
Add `try_despawn`, `try_despawn_recursive` and
`try_despawn_descendants`.
Modify `World::despawn_with_caller` to also take in a `warn` boolean
argument, which is then considered when logging the warning. Set
`log_warning` to `true` in the case of `despawn`, and `false` in the
case of `try_despawn`.
## Testing
Ran `cargo run -p ci` on macOS, it seemed fine.
# Objective
- Closes#15577
## Solution
The following functions can now also take multiple component IDs and
return multiple pointers back:
- `EntityRef::get_by_id`
- `EntityMut::get_by_id`
- `EntityMut::into_borrow_by_id`
- `EntityMut::get_mut_by_id`
- `EntityMut::into_mut_by_id`
- `EntityWorldMut::get_by_id`
- `EntityWorldMut::into_borrow_by_id`
- `EntityWorldMut::get_mut_by_id`
- `EntityWorldMut::into_mut_by_id`
If you pass in X, you receive Y:
- give a single `ComponentId`, receive a single `Ptr`/`MutUntyped`
- give a `[ComponentId; N]` (array), receive a `[Ptr; N]`/`[MutUntyped;
N]`
- give a `&[ComponentId; N]` (array), receive a `[Ptr; N]`/`[MutUntyped;
N]`
- give a `&[ComponentId]` (slice), receive a
`Vec<Ptr>`/`Vec<MutUntyped>`
- give a `&HashSet<ComponentId>`, receive a `HashMap<ComponentId,
Ptr>`/`HashMap<ComponentId, MutUntyped>`
## Testing
- Added 4 new tests.
---
## Migration Guide
- The following functions now return an `Result<_,
EntityComponentError>` instead of a `Option<_>`: `EntityRef::get_by_id`,
`EntityMut::get_by_id`, `EntityMut::into_borrow_by_id`,
`EntityMut::get_mut_by_id`, `EntityMut::into_mut_by_id`,
`EntityWorldMut::get_by_id`, `EntityWorldMut::into_borrow_by_id`,
`EntityWorldMut::get_mut_by_id`, `EntityWorldMut::into_mut_by_id`
# Objective
Fixes#15540
End-users risk using `World::flush_commands` instead of `World::flush`,
which panics if any queued commands are `spawn`. Hiding
`World::flush_commands` would help avoid calling a potentially panicky
function, and helps alleviate end-user API confusion.
## Solution
This PR updates the function visibility to crate-level, like
`World::flush_entities`, hiding it from the end-user while still making
it accessible for the tests that are currently set up.
## Testing
The change was tested by executing the available tests for `bevy_ecs`.
From what I've gathered, `World::flush_commands` is not used in any
other bevy crate. If further testing is recommended, please inform me!
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#15367.
Currently, required components can only be defined through the `require`
macro attribute. While this should be used in most cases, there are also
several instances where you may want to define requirements at runtime,
commonly in plugins.
Example use cases:
- Require components only if the relevant optional plugins are enabled.
For example, a `SleepTimer` component (for physics) is only relevant if
the `SleepPlugin` is enabled.
- Third party crates can define their own requirements for first party
types. For example, "each `Handle<Mesh>` should require my custom
rendering data components". This also gets around the orphan rule.
- Generic plugins that add marker components based on the existence of
other components, like a generic `ColliderPlugin<C: AnyCollider>` that
wants to add a `ColliderMarker` component for all types of colliders.
- This is currently relevant for the retained render world in #15320.
The `ExtractComponentPlugin<C>` should add `SyncToRenderWorld` to all
components that should be extracted. This is currently done with
observers, which is more expensive than required components, and causes
archetype moves.
- Replace some built-in components with custom versions. For example, if
`GlobalTransform` required `Transform` through `TransformPlugin`, but we
wanted to use a `CustomTransform` type, we could replace
`TransformPlugin` with our own plugin. (This specific example isn't
good, but there are likely better use cases where this may be useful)
See #15367 for more in-depth reasoning.
## Solution
Add `register_required_components::<T, R>` and
`register_required_components_with::<T, R>` methods for `Default` and
custom constructors respectively. These methods exist on `App` and
`World`.
```rust
struct BirdPlugin;
impl Plugin for BirdPlugin {
fn plugin(app: &mut App) {
// Make `Bird` require `Wings` with a `Default` constructor.
app.register_required_components::<Bird, Wings>();
// Make `Wings` require `FlapSpeed` with a custom constructor.
// Fun fact: Some hummingbirds can flutter their wings 80 times per second!
app.register_required_components_with::<Wings, FlapSpeed>(|| FlapSpeed::from_duration(1.0 / 80.0));
}
}
```
The custom constructor is a function pointer to match the `require` API,
though it could take a raw value too.
Requirement inheritance works similarly as with the `require` attribute.
If `Bird` required `FlapSpeed` directly, it would take precedence over
indirectly requiring it through `Wings`. The same logic applies to all
levels of the inheritance tree.
Note that registering the same component requirement more than once will
panic, similarly to trying to add multiple component hooks of the same
type to the same component. This avoids constructor conflicts and
confusing ordering issues.
### Implementation
Runtime requirements have two additional challenges in comparison to the
`require` attribute.
1. The `require` attribute uses recursion and macros with clever
ordering to populate hash maps of required components for each component
type. The expected semantics are that "more specific" requirements
override ones deeper in the inheritance tree. However, at runtime, there
is no representation of how "specific" each requirement is.
2. If you first register the requirement `X -> Y`, and later register `Y
-> Z`, then `X` should also indirectly require `Z`. However, `Y` itself
doesn't know that it is required by `X`, so it's not aware that it
should update the list of required components for `X`.
My solutions to these problems are:
1. Store the depth in the inheritance tree for each entry of a given
component's `RequiredComponents`. This is used to determine how
"specific" each requirement is. For `require`-based registration, these
depths are computed as part of the recursion.
2. Store and maintain a `required_by` list in each component's
`ComponentInfo`, next to `required_components`. For `require`-based
registration, these are also added after each registration, as part of
the recursion.
When calling `register_required_components`, it works as follows:
1. Get the required components of `Foo`, and check that `Bar` isn't
already a *direct* requirement.
3. Register `Bar` as a required component for `Foo`, and add `Foo` to
the `required_by` list for `Bar`.
4. Find and register all indirect requirements inherited from `Bar`,
adding `Foo` to the `required_by` list for each component.
5. Iterate through components that require `Foo`, registering the new
inherited requires for them as indirect requirements.
The runtime registration is likely slightly more expensive than the
`require` version, but it is a one-time cost, and quite negligible in
practice, unless projects have hundreds or thousands of runtime
requirements. I have not benchmarked this however.
This does also add a small amount of extra cost to the `require`
attribute for updating `required_by` lists, but I expect it to be very
minor.
## Testing
I added some tests that are copies of the `require` versions, as well as
some tests that are more specific to the runtime implementation. I might
add a few more tests though.
## Discussion
- Is `register_required_components` a good name? Originally I went for
`register_component_requirement` to be consistent with
`register_component_hooks`, but the general feature is often referred to
as "required components", which is why I changed it to
`register_required_components`.
- Should we *not* panic for duplicate requirements? If so, should they
just be ignored, or should the latest registration overwrite earlier
ones?
- If we do want to panic for duplicate, conflicting registrations,
should we at least not panic if the registrations are *exactly* the
same, i.e. same component and same constructor? The current
implementation panics for all duplicate direct registrations regardless
of the constructor.
## Next Steps
- Allow `register_required_components` to take a `Bundle` instead of a
single required component.
- I could also try to do it in this PR if that would be preferable.
- Not directly related, but archetype invariants?
# Objective
`World::flush_commands` will cause a panic with `error[B0003]: Could not
insert a bundle [...] for entity [...] because it doesn't exist in this
World` if there was a `spawn` command in the queue and you should
instead use `flush` for this but this isn't mentioned in the docs
## Solution
Add a note to the docs suggesting to use `World::flush` in this context.
This error doesn't appear to happen with `spawn_batch` so I didn't add
that to the note although you can cause it with
`commands.spawn_empty().insert(...)` but I wasn't sure that was worth
the documentation complexity as it is pretty unlikely (and equivalent to
`commands.spawn(...)`.
# Objective
Improve the documentation of `SystemParamBuilder`. Not all builder types
have documentation, and the documentation is spread around and not
linked together well.
## Solution
Reorganize `SystemParamBuilder` docs and examples. All builder types now
have their own examples, and the list of builder types is linked from
the `SystemParamBuilder` trait. Add some examples to `FilteredEntityRef`
and `FilteredEntityMut` so that `QueryParamBuilder` can reference them.
# Objective
Fixes#15394
## Solution
Observers now validate params.
System registry has a new error variant for when system running fails
due to invalid parameters.
Run once now returns a `Result<Out, RunOnceError>` instead of `Out`.
This is more inline with system registry, which also returns a result.
I'll address warning messages in #15500.
## Testing
Added one test for each case.
---
## Migration Guide
- `RunSystemOnce::run_system_once` and
`RunSystemOnce::run_system_once_with` now return a `Result<Out>` instead
of just `Out`
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
- Resolves#15453
## Solution
- Added new `World::resource_id` and `World::register_resource` methods
to support this feature
- Added new `ReflectResource::register_resource` method, and new pointer
to this new function
- Added new `ReflectComponent::register_component`
## Testing
- Tested this locally, but couldn't test the entire crate locally, just
this new feature, expect that CI will do the rest of the work.
---
## Showcase
```rs
#[derive(Component, Reflect)]
#[reflect(Component)]
struct MyComp;
let mut world = World::new();
let mut registry = TypeRegistration::of::<MyComp>();
registry.insert::<ReflectComponent>(FromType::<MyComp>::from_type());
let data = registry.data::<ReflectComponent>().unwrap();
// Its now possible to register the Component in the world this way
let component_id = data.register_component(&mut world);
// They will be the same
assert_eq!(component_id, world.component_id::<MyComp>().unwrap());
```
```rs
#[derive(Resource, Reflect)]
#[reflect(Resource)]
struct MyResource;
let mut world = World::new();
let mut registry = TypeRegistration::of::<MyResource>();
registry.insert::<ReflectResource>(FromType::<MyResource>::from_type());
let data = registry.data::<ReflectResource>().unwrap();
// Same with resources
let component_id = data.register_resource(&mut world);
// They match
assert_eq!(component_id, world.resource_id::<MyResource>().unwrap());
```
> [!NOTE]
> This is my first PR, so if something is incorrect
> or missing, please let me know :3
# Objective
- Clarifies `spawn`, `spawn_batch` and `ParallelCommands` docs about
performance and use cases
- Fixes#15472
## Solution
Add comments to `spawn`, `spawn_batch` and `ParallelCommands` to clarify
the
intended use case and link to other/better ways of doing spawning things
for
certain use cases.
# Objective
- Fixes#6370
- Closes#6581
## Solution
- Added the following lints to the workspace:
- `std_instead_of_core`
- `std_instead_of_alloc`
- `alloc_instead_of_core`
- Used `cargo +nightly fmt` with [item level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Item%5C%3A)
to split all `use` statements into single items.
- Used `cargo clippy --workspace --all-targets --all-features --fix
--allow-dirty` to _attempt_ to resolve the new linting issues, and
intervened where the lint was unable to resolve the issue automatically
(usually due to needing an `extern crate alloc;` statement in a crate
root).
- Manually removed certain uses of `std` where negative feature gating
prevented `--all-features` from finding the offending uses.
- Used `cargo +nightly fmt` with [crate level use
formatting](https://rust-lang.github.io/rustfmt/?version=v1.6.0&search=#Crate%5C%3A)
to re-merge all `use` statements matching Bevy's previous styling.
- Manually fixed cases where the `fmt` tool could not re-merge `use`
statements due to conditional compilation attributes.
## Testing
- Ran CI locally
## Migration Guide
The MSRV is now 1.81. Please update to this version or higher.
## Notes
- This is a _massive_ change to try and push through, which is why I've
outlined the semi-automatic steps I used to create this PR, in case this
fails and someone else tries again in the future.
- Making this change has no impact on user code, but does mean Bevy
contributors will be warned to use `core` and `alloc` instead of `std`
where possible.
- This lint is a critical first step towards investigating `no_std`
options for Bevy.
---------
Co-authored-by: François Mockers <francois.mockers@vleue.com>
# Objective
- Fixes#15451
## Migration Guide
- `World::init_component` has been renamed to `register_component`.
- `World::init_component_with_descriptor` has been renamed to
`register_component_with_descriptor`.
- `World::init_bundle` has been renamed to `register_bundle`.
- `Components::init_component` has been renamed to `register_component`.
- `Components::init_component_with_descriptor` has been renamed to
`register_component_with_descriptor`.
- `Components::init_resource` has been renamed to `register_resource`.
- `Components::init_non_send` had been renamed to `register_non_send`.
# Objective
Make it easier to debug why an entity doesn't match a query.
## Solution
List the entities components in `QueryEntityError::QueryDoesNotMatch`'s
message, e.g. `The query does not match the entity 0v1, which has
components foo::Bar, foo::Baz`.
This covers most cases as expected components are typically known and
filtering for change detection is rare when assessing a query by entity
id.
## Testing
Added a test confirming the new message matches the entity's components.
## Migration Guide
- `QueryEntityError` now has a lifetime. Convert it to a custom error if
you need to store it.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: poopy <gonesbird@gmail.com>
# Objective
Fixes#14467
Observers and component lifecycle hooks are allowed to perform
operations that subsequently require `Entities` to be flushed, such as
reserving a new entity. If this occurs during an `on_remove` hook or an
`OnRemove` event trigger during an `EntityWorldMut::despawn`, a panic
will occur.
## Solution
Call `world.flush_entities()` after running `on_remove` hooks/observers
during `despawn`
## Testing
Added a new test that fails before the fix and succeeds afterward.
# Objective
Fixes#14331
## Solution
- Make `Traversal` a subtrait of `ReadOnlyQueryData`
- Update implementations and usages
## Testing
- Updated unit tests
## Migration Guide
Update implementations of `Traversal`.
---------
Co-authored-by: Christian Hughes <9044780+ItsDoot@users.noreply.github.com>
Currently, Bevy restricts animation clips to animating
`Transform::translation`, `Transform::rotation`, `Transform::scale`, or
`MorphWeights`, which correspond to the properties that glTF can
animate. This is insufficient for many use cases such as animating UI,
as the UI layout systems expect to have exclusive control over UI
elements' `Transform`s and therefore the `Style` properties must be
animated instead.
This commit fixes this, allowing for `AnimationClip`s to animate
arbitrary properties. The `Keyframes` structure has been turned into a
low-level trait that can be implemented to achieve arbitrary animation
behavior. Along with `Keyframes`, this patch adds a higher-level trait,
`AnimatableProperty`, that simplifies the task of animating single
interpolable properties. Built-in `Keyframes` implementations exist for
translation, rotation, scale, and morph weights. For the most part, you
can migrate by simply changing your code from
`Keyframes::Translation(...)` to `TranslationKeyframes(...)`, and
likewise for rotation, scale, and morph weights.
An example `AnimatableProperty` implementation for the font size of a
text section follows:
#[derive(Reflect)]
struct FontSizeProperty;
impl AnimatableProperty for FontSizeProperty {
type Component = Text;
type Property = f32;
fn get_mut(component: &mut Self::Component) -> Option<&mut
Self::Property> {
Some(&mut component.sections.get_mut(0)?.style.font_size)
}
}
In order to keep this patch relatively small, this patch doesn't include
an implementation of `AnimatableProperty` on top of the reflection
system. That can be a follow-up.
This patch builds on top of the new `EntityMutExcept<>` type in order to
widen the `AnimationTarget` query to include write access to all
components. Because `EntityMutExcept<>` has some performance overhead
over an explicit query, we continue to explicitly query `Transform` in
order to avoid regressing the performance of skeletal animation, such as
the `many_foxes` benchmark. I've measured the performance of that
benchmark and have found no significant regressions.
A new example, `animated_ui`, has been added. This example shows how to
use Bevy's built-in animation infrastructure to animate font size and
color, which wasn't possible before this patch.
## Showcase
https://github.com/user-attachments/assets/1fa73492-a9ce-405a-a8f2-4aacd7f6dc97
## Migration Guide
* Animation keyframes are now an extensible trait, not an enum. Replace
`Keyframes::Translation(...)`, `Keyframes::Scale(...)`,
`Keyframes::Rotation(...)`, and `Keyframes::Weights(...)` with
`Box::new(TranslationKeyframes(...))`, `Box::new(ScaleKeyframes(...))`,
`Box::new(RotationKeyframes(...))`, and
`Box::new(MorphWeightsKeyframes(...))` respectively.
# Objective
The goal of this PR is to introduce `SystemParam` validation in order to
reduce runtime panics.
Fixes#15265
## Solution
`SystemParam` now has a new method `validate_param(...) -> bool`, which
takes immutable variants of `get_param` arguments. The returned value
indicates whether the parameter can be acquired from the world. If
parameters cannot be acquired for a system, it won't be executed,
similarly to run conditions. This reduces panics when using params like
`Res`, `ResMut`, etc. as well as allows for new, ergonomic params like
#15264 or #15302.
Param validation happens at the level of executors. All validation
happens directly before executing a system, in case of normal systems
they are skipped, in case of conditions they return false.
Warning about system skipping is primitive and subject to change in
subsequent PRs.
## Testing
Two executor tests check that all executors:
- skip systems which have invalid parameters:
- piped systems get skipped together,
- dependent systems still run correctly,
- skip systems with invalid run conditions:
- system conditions have invalid parameters,
- system set conditions have invalid parameters.
# Objective
Closes#11825
## Solution
Change return type of `get_resource_ref` and `resource_ref` from `Res`
to `Ref` and implement `From Res<T> for Ref<T>`.
# Objective
- I was running miri locally to check the UB in #15276 and it detected
an unrelated memory leak, due to the `RawCommandQueue` changes. (I
probably should have turned the leak detection off because we do
purposely leak interned string labels and I assume that's why CI didn't
detect it.)
## Solution
- The memory allocated to `RawCommandQueue` needs to be manually
dropped. This was being done for `bytes` and `cursor`, but was missed
for `panic_recovery`.
## Testing
- Ran miri locally and the related memory leaks errors when away.
Enabled `check-private-items` in `clippy.toml` and then fixed the
resulting errors. Most of these were simply misformatted and of the
remaining:
- ~Added `#[allow(clippy::missing_safety_doc)]` to~ Removed unsafe from
a pair of functions in `bevy_utils/futures` which are only unsafe so
that they can be passed to a function which requires `unsafe fn`
- Removed `unsafe` from `UnsafeWorldCell::observers` as from what I can
tell it is always safe like `components`, `bundles` etc. (this should be
checked)
- Added safety docs to:
- `Bundles::get_storage_unchecked`: Based on the function that writes to
`dynamic_component_storages`
- `Bundles::get_storages_unchecked`: Based on the function that writes
to `dynamic_bundle_storages`
- `QueryIterationCursor::init_empty`: Duplicated from `init`
- `QueryIterationCursor::peek_last`: Thanks Giooschi (also added
internal unsafe blocks)
- `tests::drop_ptr`: Moved safety comment out to the doc string
This lint would also apply to `missing_errors_doc`, `missing_panics_doc`
and `unnecessary_safety_doc` if we chose to enable any of those at some
point, although there is an open
[issue](https://github.com/rust-lang/rust-clippy/issues/13074) to
separate these options.
This commit adds two new `WorldQuery` types: `EntityRefExcept` and
`EntityMutExcept`. These types work just like `EntityRef` and
`EntityMut`, but they prevent access to a statically-specified list of
components. For example, `EntityMutExcept<(AnimationPlayer,
Handle<AnimationGraph>)>` provides mutable access to all components
except for `AnimationPlayer` and `Handle<AnimationGraph>`. These types
are useful when you need to be able to process arbitrary queries while
iterating over the results of another `EntityMut` query.
The motivating use case is *generalized animation*, which is an upcoming
feature that allows animation of any component property, not just
rotation, translation, scaling, or morph weights. To implement this, we
must change the current `AnyOf<(&mut Transform, &mut MorphWeights)>` to
instead be `EntityMutExcept<(AnimationPlayer, Handle<AnimationGraph>)>`.
It's possible to use `FilteredEntityMut` in conjunction with a
dynamically-generated system instead, but `FilteredEntityMut` isn't
optimized for the use case of a large number of allowed components
coupled with a small set of disallowed components. No amount of
optimization of `FilteredEntityMut` produced acceptable performance on
the `many_foxes` benchmark. `Query<EntityMut, Without<AnimationPlayer>>`
will not suffice either, as it's legal and idiomatic for an
`AnimationTarget` and an `AnimationPlayer` to coexist on the same
entity.
An alternate proposal was to implement a somewhat-more-general
`Except<Q, CL>` feature, where Q is a `WorldQuery` and CL is a
`ComponentList`. I wasn't able to implement that proposal in a
reasonable way, because of the fact that methods like
`EntityMut::get_mut` and `EntityRef::get` are inherent methods instead
of methods on `WorldQuery`, and therefore there was no way to delegate
methods like `get` and `get_mut` to the inner query in a generic way.
Refactoring those methods into a trait would probably be possible.
However, I didn't see a use case for a hypothetical `Except` with
arbitrary queries: `Query<Except<(&Transform, &Visibility),
Visibility>>` would just be a complicated equivalent to
`Query<&Transform>`, for instance. So, out of a desire for simplicity, I
omitted a generic `Except` mechanism.
I've tested the performance of generalized animation on `many_foxes` and
found that, with this patch, `animate_targets` has a 7.4% slowdown over
`main`. With `FilteredEntityMut` optimized to use `Arc<Access>`, the
slowdown is 75.6%, due to contention on the reference count. Without
`Arc<Access>`, the slowdown is even worse, over 2x.
## Testing
New tests have been added that check that `EntityRefExcept` and
`EntityMutExcept` allow and disallow access to components properly and
that the query engine can correctly reject conflicting queries involving
those types.
A Tracy profile of `many_foxes` with 10,000 foxes showing generalized
animation using `FilteredEntityMut` (red) vs. main (yellow) is as
follows:
A Tracy profile of `many_foxes` with 10,000 foxes showing generalized
animation using this `EntityMutExcept` (yellow) vs. main (red) is as
follows:
# Objective
- Fixes#15106
## Solution
- Trivial refactor to rename the method. The duplicate method `push` was
removed as well. This will simpify the API and make the semantics more
clear. `Add` implies that the action happens immediately, whereas in
reality, the command is queued to be run eventually.
- `ChildBuilder::add_command` has similarly been renamed to
`queue_command`.
## Testing
Unit tests should suffice for this simple refactor.
---
## Migration Guide
- `Commands::add` and `Commands::push` have been replaced with
`Commnads::queue`.
- `ChildBuilder::add_command` has been renamed to
`ChildBuilder::queue_command`.
# Objective
- fix#12853
- Make `Table::allocate` faster
## Solution
The PR consists of multiple steps:
1) For the component data: create a new data-structure that's similar to
`BlobVec` but doesn't store `len` & `capacity` inside of it: "BlobArray"
(name suggestions welcome)
2) For the `Tick` data: create a new data-structure that's similar to
`ThinSlicePtr` but supports dynamic reallocation: "ThinArrayPtr" (name
suggestions welcome)
3) Create a new data-structure that's very similar to `Column` that
doesn't store `len` & `capacity` inside of it: "ThinColumn"
4) Adjust the `Table` implementation to use `ThinColumn` instead of
`Column`
The result is that only one set of `len` & `capacity` is stored in
`Table`, in `Table::entities`
### Notes Regarding Performance
Apart from shaving off some excess memory in `Table`, the changes have
also brought noteworthy performance improvements:
The previous implementation relied on `Vec::reserve` &
`BlobVec::reserve`, but that redundantly repeated the same if statement
(`capacity` == `len`). Now that check could be made at the `Table` level
because the capacity and length of all the columns are synchronized;
saving N branches per allocation. The result is a respectable
performance improvement per every `Table::reserve` (and subsequently
`Table::allocate`) call.
I'm hesitant to give exact numbers because I don't have a lot of
experience in profiling and benchmarking, but these are the results I
got so far:
*`add_remove_big/table` benchmark after the implementation:*
*`add_remove_big/table` benchmark in main branch (measured in comparison
to the implementation):*
*`add_remove_very_big/table` benchmark after the implementation:*
*`add_remove_very_big/table` benchmark in main branch (measured in
comparison to the implementation):*
cc @james7132 to verify
---
## Changelog
- New data-structure that's similar to `BlobVec` but doesn't store `len`
& `capacity` inside of it: `BlobArray`
- New data-structure that's similar to `ThinSlicePtr` but supports
dynamic allocation:`ThinArrayPtr`
- New data-structure that's very similar to `Column` that doesn't store
`len` & `capacity` inside of it: `ThinColumn`
- Adjust the `Table` implementation to use `ThinColumn` instead of
`Column`
- New benchmark: `add_remove_very_big` to benchmark the performance of
spawning a lot of entities with a lot of components (15) each
## Migration Guide
`Table` now uses `ThinColumn` instead of `Column`. That means that
methods that previously returned `Column`, will now return `ThinColumn`
instead.
`ThinColumn` has a much more limited and low-level API, but you can
still achieve the same things in `ThinColumn` as you did in `Column`.
For example, instead of calling `Column::get_added_tick`, you'd call
`ThinColumn::get_added_ticks_slice` and index it to get the specific
added tick.
---------
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
Smaller scoped version of #13375 without the `_mut` variants which
currently have unsoundness issues.
## Solution
Same as #13375, but without the `_mut` variants.
## Testing
- The same test from #13375 is reused.
---
## Migration Guide
- Renamed `FilteredEntityRef::components` to
`FilteredEntityRef::accessed_components` and
`FilteredEntityMut::components` to
`FilteredEntityMut::accessed_components`.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Co-authored-by: Periwink <charlesbour@gmail.com>
# Objective
- Fixes#14860
## Solution
- Added a line of documentation to `FromWorld`'s trait definition
mention the `Default` blanket implementation.
- Added custom documentation to the `from_world` method for the
`Default` blanket implementation. This ensures when inspecting the
`from_world` function within an IDE, the tooltip will explicitly state
the `default()` method will be used for any `Default` types.
## Testing
- CI passes.
## Introduction
This is the first step in my [Next Generation Scene / UI
Proposal](https://github.com/bevyengine/bevy/discussions/14437).
Fixes https://github.com/bevyengine/bevy/issues/7272#14800.
Bevy's current Bundles as the "unit of construction" hamstring the UI
user experience and have been a pain point in the Bevy ecosystem
generally when composing scenes:
* They are an additional _object defining_ concept, which must be
learned separately from components. Notably, Bundles _are not present at
runtime_, which is confusing and limiting.
* They can completely erase the _defining component_ during Bundle init.
For example, `ButtonBundle { style: Style::default(), ..default() }`
_makes no mention_ of the `Button` component symbol, which is what makes
the Entity a "button"!
* They are not capable of representing "dependency inheritance" without
completely non-viable / ergonomically crushing nested bundles. This
limitation is especially painful in UI scenarios, but it applies to
everything across the board.
* They introduce a bunch of additional nesting when defining scenes,
making them ugly to look at
* They introduce component name "stutter": `SomeBundle { component_name:
ComponentName::new() }`
* They require copious sprinklings of `..default()` when spawning them
in Rust code, due to the additional layer of nesting
**Required Components** solve this by allowing you to define which
components a given component needs, and how to construct those
components when they aren't explicitly provided.
This is what a `ButtonBundle` looks like with Bundles (the current
approach):
```rust
#[derive(Component, Default)]
struct Button;
#[derive(Bundle, Default)]
struct ButtonBundle {
pub button: Button,
pub node: Node,
pub style: Style,
pub interaction: Interaction,
pub focus_policy: FocusPolicy,
pub border_color: BorderColor,
pub border_radius: BorderRadius,
pub image: UiImage,
pub transform: Transform,
pub global_transform: GlobalTransform,
pub visibility: Visibility,
pub inherited_visibility: InheritedVisibility,
pub view_visibility: ViewVisibility,
pub z_index: ZIndex,
}
commands.spawn(ButtonBundle {
style: Style {
width: Val::Px(100.0),
height: Val::Px(50.0),
..default()
},
focus_policy: FocusPolicy::Block,
..default()
})
```
And this is what it looks like with Required Components:
```rust
#[derive(Component)]
#[require(Node, UiImage)]
struct Button;
commands.spawn((
Button,
Style {
width: Val::Px(100.0),
height: Val::Px(50.0),
..default()
},
FocusPolicy::Block,
));
```
With Required Components, we mention only the most relevant components.
Every component required by `Node` (ex: `Style`, `FocusPolicy`, etc) is
automatically brought in!
### Efficiency
1. At insertion/spawn time, Required Components (including recursive
required components) are initialized and inserted _as if they were
manually inserted alongside the given components_. This means that this
is maximally efficient: there are no archetype or table moves.
2. Required components are only initialized and inserted if they were
not manually provided by the developer. For the code example in the
previous section, because `Style` and `FocusPolicy` are inserted
manually, they _will not_ be initialized and inserted as part of the
required components system. Efficient!
3. The "missing required components _and_ constructors needed for an
insertion" are cached in the "archetype graph edge", meaning they aren't
computed per-insertion. When a component is inserted, the "missing
required components" list is iterated (and that graph edge (AddBundle)
is actually already looked up for us during insertion, because we need
that for "normal" insert logic too).
### IDE Integration
The `#[require(SomeComponent)]` macro has been written in such a way
that Rust Analyzer can provide type-inspection-on-hover and `F12` /
go-to-definition for required components.
### Custom Constructors
The `require` syntax expects a `Default` constructor by default, but it
can be overridden with a custom constructor:
```rust
#[derive(Component)]
#[require(
Node,
Style(button_style),
UiImage
)]
struct Button;
fn button_style() -> Style {
Style {
width: Val::Px(100.0),
..default()
}
}
```
### Multiple Inheritance
You may have noticed by now that this behaves a bit like "multiple
inheritance". One of the problems that this presents is that it is
possible to have duplicate requires for a given type at different levels
of the inheritance tree:
```rust
#[derive(Component)
struct X(usize);
#[derive(Component)]
#[require(X(x1))
struct Y;
fn x1() -> X {
X(1)
}
#[derive(Component)]
#[require(
Y,
X(x2),
)]
struct Z;
fn x2() -> X {
X(2)
}
// What version of X is inserted for Z?
commands.spawn(Z);
```
This is allowed (and encouraged), although this doesn't appear to occur
much in practice. First: only one version of `X` is initialized and
inserted for `Z`. In the case above, I think we can all probably agree
that it makes the most sense to use the `x2` constructor for `X`,
because `Y`'s `x1` constructor exists "beneath" `Z` in the inheritance
hierarchy; `Z`'s constructor is "more specific".
The algorithm is simple and predictable:
1. Use all of the constructors (including default constructors) directly
defined in the spawned component's require list
2. In the order the requires are defined in `#[require()]`, recursively
visit the require list of each of the components in the list (this is a
depth Depth First Search). When a constructor is found, it will only be
used if one has not already been found.
From a user perspective, just think about this as the following:
1. Specifying a required component constructor for `Foo` directly on a
spawned component `Bar` will result in that constructor being used (and
overriding existing constructors lower in the inheritance tree). This is
the classic "inheritance override" behavior people expect.
2. For cases where "multiple inheritance" results in constructor
clashes, Components should be listed in "importance order". List a
component earlier in the requirement list to initialize its inheritance
tree earlier.
Required Components _does_ generally result in a model where component
values are decoupled from each other at construction time. Notably, some
existing Bundle patterns use bundle constructors to initialize multiple
components with shared state. I think (in general) moving away from this
is necessary:
1. It allows Required Components (and the Scene system more generally)
to operate according to simple rules
2. The "do arbitrary init value sharing in Bundle constructors" approach
_already_ causes data consistency problems, and those problems would be
exacerbated in the context of a Scene/UI system. For cases where shared
state is truly necessary, I think we are better served by observers /
hooks.
3. If a situation _truly_ needs shared state constructors (which should
be rare / generally discouraged), Bundles are still there if they are
needed.
## Next Steps
* **Require Construct-ed Components**: I have already implemented this
(as defined in the [Next Generation Scene / UI
Proposal](https://github.com/bevyengine/bevy/discussions/14437). However
I've removed `Construct` support from this PR, as that has not landed
yet. Adding this back in requires relatively minimal changes to the
current impl, and can be done as part of a future Construct pr.
* **Port Built-in Bundles to Required Components**: This isn't something
we should do right away. It will require rethinking our public
interfaces, which IMO should be done holistically after the rest of Next
Generation Scene / UI lands. I think we should merge this PR first and
let people experiment _inside their own code with their own Components_
while we wait for the rest of the new scene system to land.
* **_Consider_ Automatic Required Component Removal**: We should
evaluate _if_ automatic Required Component removal should be done. Ex:
if all components that explicitly require a component are removed,
automatically remove that component. This issue has been explicitly
deferred in this PR, as I consider the insertion behavior to be
desirable on its own (and viable on its own). I am also doubtful that we
can find a design that has behavior we actually want. Aka: can we
_really_ distinguish between a component that is "only there because it
was automatically inserted" and "a component that was necessary / should
be kept". See my [discussion response
here](https://github.com/bevyengine/bevy/discussions/14437#discussioncomment-10268668)
for more details.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: BD103 <59022059+BD103@users.noreply.github.com>
Co-authored-by: Pascal Hertleif <killercup@gmail.com>
# Objective
I tried writing something like this in my project
```rust
.observe(|e: Trigger<OnAdd, Skeleton>| {
panic!("Skeletoned! {e:?}");
});
```
and it didn't compile.
Having `Debug` trait defined on `Trigger` event will ease debugging the
observers a little bit.
## Solution
Add a bespoke `Debug` implementation when both the bundle and the event
have `Debug` implemented for them.
## Testing
I've added `println!("{trigger:#?}");` to the [observers
example](938d810766/examples/ecs/observers.rs (L124))
and it compiled!
Caveats with this PR are:
- removing this implementation if for any reason we will need it, will
be a breaking change
- the implementation is manually generated, which adds potential toil
when changing the `Trigger` structure
## Showcase
Log output:
```rust
on_add_mine: Trigger {
event: OnAdd,
propagate: false,
trigger: ObserverTrigger {
observer: 2v1#4294967298,
event_type: ComponentId(
0,
),
entity: 454v1#4294967750,
},
_marker: PhantomData<observers::Mine>,
}
```
Thank you for maintaining this engine! 🧡
