# Objective
`RelatedSpawnerCommands` offers methods to get the underlying
`Commands`.
`RelatedSpawner` does not expose the inner `World` reference so far.
I currently want to write extension traits for both of them but I need
to duplicate the whole API for the latter because I cannot get it's
`&mut World`.
## Solution
Add methods for immutable and mutable `World` access
# Objective
Currently, `bevy_ecs`'s `children!` macro only supports spawning up to
twelve children at once. Ideally there would be no limit.
## Solution
`children!` is limited because `SpawnableList`, [the primary trait bound
here](https://docs.rs/bevy/0.16.0-rc.5/bevy/ecs/hierarchy/struct.Children.html#method.spawn),
uses the fake variadics pattern on tuples of up to twelve elements.
However, since a tuple itself implements `SpawnableList`, we can simply
nest tuples of entities when we run out of room.
This PR achieves this using `macro_rules` macros with a bit of brute
force, following [some discussion on
Discord](https://discord.com/channels/691052431525675048/692572690833473578/1362174415458013314).
If we create patterns for lists of up to eleven bundles, then use a
repetition pattern to handle the rest, we can "special-case" the
recursion into a nested tuple.
In principle, this would permit an arbitrary number of children, but
Rust's recursion limits will cut things short at around 1400 elements by
default. Of course, it's generally not a good idea to stick that many
bundles in a single invocation, but it might be worth mentioning in the
docs.
## Implementation notes
### Why are cases 0-11 expanded by hand?
We could make use of a tertiary macro:
```rs
macro_rules! recursive_spawn {
// so that this...
($a:expr, $b:expr) => {
(
$crate::spawn::Spawn($a),
$crate::spawn::Spawn($b),
)
};
// becomes this...
($a:expr, $b:expr) => {
$crate::spawn_tuple!($a, $b)
};
}
```
But I already feel a little bad exporting `recursive_spawn`. I'd really
like to avoid exposing more internals, even if they are annotated with
`#[doc(hidden)]`. If I had to guess, I'd say it'll also make the
expansion a tiny bit slower.
### Do we really need to handle up to twelve elements in the macro?
The macro is a little long, but doing it this way maximizes the
"flatness" of the types to be spawned. This should improve the codegen a
bit and makes the macro output a little bit easier to look at.
## Future work
The `related!` macro is essentially the same as `children!`, so if this
direction is accepted, `related!` should receive the same treatment. I
imagine we'd want to extract out the `recursive_spawn` macro into its
own file since it can be used for both. If this should be tackled in
this PR, let me know!
## Testing
This change is fairly trivial, but I added a single test to verify that
it compiles and nothing goes wrong once recursion starts happening. It's
pretty easy to verify that the change works in practice -- just spawn
over twelve entities as children at once!
# Objective
Contributes to #18741 and #18453.
## Solution
Deprecate `SimpleExecutor`. If users run into migration issues, we can
backtrack. Otherwise, we follow this up with #18741
We can't easily deprecate the module too because of
[this](https://github.com/rust-lang/rust/issues/47238).
## Testing
CI
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Cyrill Schenkel <cyrill.schenkel@gmail.com>
# Objective
- bevy removed `Observe` type parameters in #15151 ,it enables merging
`Observer` and `ObserverState ` into a single component. with this
consolidation ,we can improve efficiency while reducing boilerplate.
## Solution
- remove `ObserverState `and merge it into `Observer`
## Testing
40%~60% performance win due to removal of redundant look up.
This also improves ergonomics when using dynamic observer
```rust
// previously
world.spawn(ObserverState {
// SAFETY: we registered `event_a` above and it matches the type of EventA
descriptor: unsafe { ObserverDescriptor::default().with_events(vec![event_a]) },
runner: |mut world, _trigger, _ptr, _propagate| {
world.resource_mut::<Order>().observed("event_a");
},
..Default::default()
});
// now
let observe = unsafe {
Observer::with_dynamic_runner(|mut world, _trigger, _ptr, _propagate| {
world.resource_mut::<Order>().observed("event_a");
})
.with_event(event_a)
};
world.spawn(observe);
```
# Objective
Simplify code in the `SingleThreadedExecutor` by removing a special case
for exclusive systems.
The `SingleThreadedExecutor` runs systems without immediately applying
deferred buffers. That required calling `run_unsafe()` instead of
`run()`, but that would `panic` for exclusive systems, so the code also
needed a special case for those. Following #18076 and #18406, we have a
`run_without_applying_deferred` method that has the exact behavior we
want and works on exclusive systems.
## Solution
Replace the code in `SingleThreadedExecutor` that runs systems with a
single call to `run_without_applying_deferred()`. Also add this as a
wrapper in the `__rust_begin_short_backtrace` module to preserve the
special behavior for backtraces.
# Objective
It has long been a todo item in the ecs to create a `BundleRemover`
alongside the inserter, spawner, etc.
This is an uncontroversial first step of #18514.
## Solution
Move existing code from complex helper functions to one generalized
`BundleRemover`.
## Testing
Existing tests.
# Objective
Let `FilteredEntityRef` and `FilteredEntityMut` receive access when
nested inside tuples or `#[derive(QueryData)]` types. Make sure to
exclude any access that would conflict with other subqueries!
Fixes#14349
## Solution
Replace `WorldQuery::set_access(state, access)` with a new method,
`QueryData::provide_extra_access(state, access, available_access)`, that
passes both the total available access and the currently used access.
This is called after `WorldQuery::update_component_access()`, so any
access used by ordinary subqueries will be known. `FilteredEntityRef`
and `FilteredEntityMut` can use the combination to determine how much
access they can safely take, while tuples can safely pass those
parameters directly to their subqueries.
This requires a new `Access::remove_conflicting_access()` method that
can be used to remove any access that would conflict with existing
access. Implementing this method was easier by first factoring some
common set manipulation code out of `Access::extend`. I can extract that
refactoring to a separate PR if desired.
Have `FilteredEntity(Ref|Mut)` store `Access` instead of
`FilteredAccess` because they do not need to keep track of the filter.
This was necessary in an early draft but no longer is. I left it in
because it's small and I'm touching that code anyway, but I can extract
it to a separate PR if desired.
# Objective
Fixes#17803
## Solution
- Add an `Allows<T>` `QueryFilter` that adds archetypal access for `T`
- Fix access merging to include archetypal from both sides
## Testing
- Added a case to the unit test for the application of
`DefaultQueryFilters`
# Objective
Based on and closes#18054, this PR builds on #18035 and #18147 to
remove:
- `Commands::insert_or_spawn_batch`
- `Entities::alloc_at_without_replacement`
- `Entities::alloc_at`
- `entity::AllocAtWithoutReplacement`
- `World::insert_or_spawn_batch`
- `World::insert_or_spawn_batch_with_caller`
## Testing
Just removing unused, deprecated code, so no new tests. Note that as of
writing, #18035 is still under testing and review.
## Future Work
Per
[this](https://github.com/bevyengine/bevy/issues/18054#issuecomment-2689088899)
comment on #18054, there may be additional performance improvements
possible to the entity allocator now that `alloc_at` no longer is
supported. At a glance, I don't see anything obvious to improve, but it
may be worth further investigation in the future.
---------
Co-authored-by: JaySpruce <jsprucebruce@gmail.com>
# Objective
Stop using `ArchetypeComponentId` in the executor. These IDs will grow
even more quickly with relations, and the size may start to degrade
performance.
## Solution
Have systems expose their `FilteredAccessSet<ComponentId>`, and have the
executor use that to determine which systems conflict. This can be
determined statically, so determine all conflicts during initialization
and only perform bit tests when running.
## Testing
I ran many_foxes and didn't see any performance changes. It's probably
worth testing this with a wider range of realistic schedules to see
whether the reduced concurrency has a cost in practice, but I don't know
what sort of test cases to use.
## Migration Guide
The schedule will now prevent systems from running in parallel if there
*could* be an archetype that they conflict on, even if there aren't
actually any. For example, these systems will now conflict even if no
entity has both `Player` and `Enemy` components:
```rust
fn player_system(query: Query<(&mut Transform, &Player)>) {}
fn enemy_system(query: Query<(&mut Transform, &Enemy)>) {}
```
To allow them to run in parallel, use `Without` filters, just as you
would to allow both queries in a single system:
```rust
// Either one of these changes alone would be enough
fn player_system(query: Query<(&mut Transform, &Player), Without<Enemy>>) {}
fn enemy_system(query: Query<(&mut Transform, &Enemy), Without<Player>>) {}
```
# Objective
Prevent using exclusive systems as observers. Allowing them is unsound,
because observers are only expected to have `DeferredWorld` access, and
the observer infrastructure will keep pointers that are invalidated by
the creation of `&mut World`.
See
https://github.com/bevyengine/bevy/actions/runs/14778342801/job/41491517847?pr=19011
for a MIRI failure in a recent PR caused by an exclusive system being
used as an observer in a test.
## Solution
Have `Observer::new` panic if `System::is_exclusive()` is true. Document
that method, and methods that call it, as panicking.
(It should be possible to express this in the type system so that the
calls won't even compile, but I did not want to attempt that.)
## Testing
Added a unit test that calls `World::add_observer` with an exclusive
system.
# Objective
I've been tinkering with ECS insertion/removal lately, and noticed that
sparse sets just... don't interact with `InsertMode` at all. Sure
enough, using `insert_if_new` with a sparse component does the same
thing as `insert`.
# Solution
- Add a check in `BundleInfo::write_components` to drop the new value if
the entity already has the component and `InsertMode` is `Keep`.
- Add necessary methods to sparse set internals to fetch the drop
function.
# Testing
Minimal reproduction:
<details>
<summary>Code</summary>
```
use bevy::prelude::*;
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(PostStartup, component_print)
.run();
}
#[derive(Component)]
#[component(storage = "SparseSet")]
struct SparseComponent(u32);
fn setup(mut commands: Commands) {
let mut entity = commands.spawn_empty();
entity.insert(SparseComponent(1));
entity.insert(SparseComponent(2));
let mut entity = commands.spawn_empty();
entity.insert(SparseComponent(3));
entity.insert_if_new(SparseComponent(4));
}
fn component_print(query: Query<&SparseComponent>) {
for component in &query {
info!("{}", component.0);
}
}
```
</details>
Here it is on Bevy Playground (0.15.3):
https://learnbevy.com/playground?share=2a96a68a81e804d3fdd644a833c1d51f7fa8dd33fc6192fbfd077b082a6b1a41
Output on `main`:
```
2025-05-04T17:50:50.401328Z INFO system{name="fork::component_print"}: fork: 2
2025-05-04T17:50:50.401583Z INFO system{name="fork::component_print"}: fork: 4
```
Output with this PR :
```
2025-05-04T17:51:33.461835Z INFO system{name="fork::component_print"}: fork: 2
2025-05-04T17:51:33.462091Z INFO system{name="fork::component_print"}: fork: 3
```
# Objective
`BTreeSet` doesn't implement `RelationshipSourceCollection`.
## Solution
Implement it.
## Testing
`cargo clippy`
---
## Showcase
You can now use `BTreeSet` in a `RelationshipTarget`
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
Create a `When` system param wrapper for skipping systems that fail
validation.
Currently, the `Single` and `Populated` parameters cause systems to skip
when they fail validation, while the `Res` family causes systems to
error. Generalize this so that any fallible parameter can be used either
to skip a system or to raise an error. A parameter used directly will
always raise an error, and a parameter wrapped in `When<P>` will always
cause the system to be silently skipped.
~~Note that this changes the behavior for `Single` and `Populated`. The
current behavior will be available using `When<Single>` and
`When<Populated>`.~~
Fixes#18516
## Solution
Create a `When` system param wrapper that wraps an inner parameter and
converts all validation errors to `skipped`.
~~Change the behavior of `Single` and `Populated` to fail by default.~~
~~Replace in-engine use of `Single` with `When<Single>`. I updated the
`fallible_systems` example, but not all of the others. The other
examples I looked at appeared to always have one matching entity, and it
seemed more clear to use the simpler type in those cases.~~
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
Co-authored-by: François Mockers <mockersf@gmail.com>
# Objective
We have methods to:
- Add related entities
- Replace related entities
- Remove specific related entities
We don't have a method the remove all related entities so.
## Solution
Add a method to remove all related entities.
## Testing
A new test case.
# Objective
When implementing `SystemParam` for an object which contains a mutable
reference to World, which cannot be derived due to a required lifetime
parameter, it's necessary to check that there aren't any conflicts.
As far as I know, the is_empty method is the only way provided to check
for no conflicts at all
# Objective
Fixes#18857.
## Solution
Add the requested method, and a `try_` variant as well.
## Testing
It compiles, doctests succeed, and is trivial enough that I don't think
it needs a unit test (correct me if I'm wrong though).
# Objective
A small typo was found on `bevy_ecs/examples/event.rs`.
I know it's very minor but I'd think fixing it would still help others
in the long run.
## Solution
Fix the typo.
## Testing
I don't think this is necessary.
# Objective
One to one relationships (added in
https://github.com/bevyengine/bevy/pull/18087) can currently easily be
invalidated by having two entities relate to the same target.
Alternative to #18817 (removing one-to-one relationships)
## Solution
Panic if a RelationshipTarget is already targeted. Thanks @urben1680 for
the idea!
---------
Co-authored-by: François Mockers <mockersf@gmail.com>
Fixes#18834.
`EntityWorldMut::remove_children` and `EntityCommands::remove_children`
were removed in the relationships overhaul (#17398) and never got
replaced.
I don't *think* this was intentional (the methods were never mentioned
in the PR or its comments), but I could've missed something.
Fixes a small mix-up from #18058, which added bulk relationship
replacement methods.
`EntityCommands::replace_related_with_difference` calls
`EntityWorldMut::replace_children_with_difference` instead of
`EntityWorldMut::replace_related_with_difference`, which means it always
operates on the `ChildOf` relationship instead of the `R: Relationship`
generic it's provided.
`EntityCommands::replace_children_with_difference` takes an `R:
Relationship` generic that it shouldn't, but it accidentally works
correctly on `main` because it calls the above method.
# Objective
After #17967, closures which always panic no longer satisfy various Bevy
traits. Principally, this affects observers, systems and commands.
While this may seem pointless (systems which always panic are kind of
useless), it is distinctly annoying when using the `todo!` macro, or
when writing tests that should panic.
Fixes#18778.
## Solution
- Add failing tests to demonstrate the problem
- Add the trick from
[`never_say_never`](https://docs.rs/never-say-never/latest/never_say_never/)
to name the `!` type on stable Rust
- Write looots of docs explaining what the heck is going on and why
we've done this terrible thing
## To do
Unfortunately I couldn't figure out how to avoid conflicting impls, and
I am out of time for today, the week and uh the week after that.
Vacation! If you feel like finishing this for me, please submit PRs to
my branch and I can review and press the button for it while I'm off.
Unless you're Cart, in which case you have write permissions to my
branch!
- [ ] fix for commands
- [ ] fix for systems
- [ ] fix for observers
- [ ] revert https://github.com/bevyengine/bevy-website/pull/2092/
## Testing
I've added a compile test for these failure cases and a few adjacent
non-failing cases (with explicit return types).
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
The parameter `In` of `call_inner` is completely unconstrained by its
arguments and return type. We are only able to infer it by assuming that
the only associated type equal to `In::Param<'_>` is `In::Param<'_>`
itself. It could just as well be some other associated type which only
normalizes to `In::Param<'_>`. This will change with the next-generation
trait solver and was encountered by a crater run
https://github.com/rust-lang/rust/pull/133502-
cc
https://github.com/rust-lang/trait-system-refactor-initiative/issues/168
I couldn't think of a cleaner alternative here. I first tried to just
provide `In` as an explicit type parameter. This is also kinda ugly as I
need to provide a variable number of them and `${ignore(..)}` is
currently still unstable https://github.com/rust-lang/rust/issues/83527.
Sorry for the inconvenience. Also fun that this function exists to avoid
a separate solver bug in the first place 😅
# Objective
The goal of `bevy_platform_support` is to provide a set of platform
agnostic APIs, alongside platform-specific functionality. This is a high
traffic crate (providing things like HashMap and Instant). Especially in
light of https://github.com/bevyengine/bevy/discussions/18799, it
deserves a friendlier / shorter name.
Given that it hasn't had a full release yet, getting this change in
before Bevy 0.16 makes sense.
## Solution
- Rename `bevy_platform_support` to `bevy_platform`.
# Objective
- Piped systems are an edge case that we missed when reworking system
parameter validation.
- Fixes#18755.
## Solution
- Validate the parameters for both systems, ~~combining the errors if
both failed validation~~ by simply using an early out.
- ~~Also fix the same bug for combinator systems while we're here.~~
## Testing
I've added a large number of tests checking the behavior under various
permutations. These are separate tests, rather than one mega test
because a) it's easier to track down bugs that way and b) many of these
are `should_panic` tests, which will halt the evaluation of the rest of
the test!
I've also added a test for exclusive systems being pipeable because we
don't have one and I was very surprised that that works!
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
Fixes#18678
## Solution
Moved the current `with_related` method to `with_relationships` and
added a new `with_related` that uses a bundle.
I'm not entirely sold on the name just yet, if anyone has any ideas let
me know.
## Testing
I wasn't able to test these changes because it crashed my computer every
time I tried (fun). But there don't seem to be any tests that use the
old `with_related` method so it should be fine, hopefully
## Showcase
```rust
commands.spawn_empty()
.with_related::<Relationship>(Name::new("Related thingy"))
.with_relationships(|rel| {
rel.spawn(Name::new("Second related thingy"));
});
```
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Allow viewing and setting the added tick for change detection aware
data, to allow operations like checking if the value has been modified
since first being added, and spoofing that state (i.e. returning the
value to default in place without a remove/insert dance)
## Solution
- Added corresponding functions matching the existing `changed` API:
- `fn added(&self) -> Tick`
- `fn set_added(&mut self)`
- `fn set_last_added(&mut self, last_added: Tick)`
Discussed on discord @
https://canary.discord.com/channels/691052431525675048/749335865876021248/1358718892465193060
## Testing
- Running the bevy test suite by.. making a PR, heck.
- No new tests were introduced due to triviality (i.e. I don't know what
to test about this API, and the corresponding API for `changed` is
similarly lacking tests.)
---------
Co-authored-by: moonheart08 <moonheart08@users.noreply.github.com>
Co-authored-by: SpecificProtagonist <vincentjunge@posteo.net>
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
Clarify information in the docs about the bundle removal commands.
## Solution
Added information about how the intersection of components are removed.
# Objective
- The `#[deprecated]` attributes supports a `since` field, which
documents in which version an item was deprecated. This field is visible
in `rustdoc`.
- We inconsistently use `since` throughout the project.
For an example of what `since` renders as, take a look at
`ChildOf::get()`:
```rust
/// The parent entity of this child entity.
#[deprecated(since = "0.16.0", note = "Use child_of.parent() instead")]
#[inline]
pub fn get(&self) -> Entity {
self.0
}
```
## Solution
- Add `since = "0.16.0"` to all `#[deprecated]` attributes that do not
already use it.
- Add an example of deprecating a struct with the `since` field in the
migration guide document.
I would appreciate if this could be included in 0.16's release, as its a
low-risk documentation improvement that is valuable for the release, but
I'd understand if this was cut.
## Testing
You can use `cargo doc` to inspect the rendered form of
`#[deprecated(since = "0.16.0", ...)]`.
# Objective
Newest installment of the #16547 series.
In #18319 we introduced `Entity` defaults to accomodate the most common
use case for these types, however that resulted in the switch of the `T`
and `N` generics of `UniqueEntityArray`.
Swapping generics might be somewhat acceptable for `UniqueEntityArray`,
it is not at all acceptable for map and set types, which we would make
generic over `T: EntityEquivalent` in #18408.
Leaving these defaults in place would result in a glaring inconsistency
between these set collections and the others.
Additionally, the current standard in the engine is for "entity" to mean
`Entity`. APIs could be changed to accept `EntityEquivalent`, however
that is a separate and contentious discussion.
## Solution
Name these set collections `UniqueEntityEquivalent*`, and retain the
`UniqueEntity*` name for an alias of the `Entity` case.
While more verbose, this allows for all generics to be in proper order,
full consistency between all set types*, and the "entity" name to be
restricted to `Entity`.
On top of that, `UniqueEntity*` now always have 1 generic less, when
previously this was not enforced for the default case.
*`UniqueEntityIter<I: Iterator<T: EntityEquivalent>>` is the sole
exception to this. Aliases are unable to enforce bounds
(`lazy_type_alias` is needed for this), so for this type, doing this
split would be a mere suggestion, and in no way enforced.
Iterator types are rarely ever named, and this specific one is intended
to be aliased when it sees more use, like we do for the corresponding
set collection iterators.
Furthermore, the `EntityEquivalent` precursor `Borrow<Entity>` was used
exactly because of such iterator bounds!
Because of that, we leave it as is.
While no migration guide for 0.15 users, for those that upgrade from
main:
`UniqueEntityVec<T>` -> `UniqueEntityEquivalentVec<T>`
`UniqueEntitySlice<T>` -> `UniqueEntityEquivalentSlice<T>`
`UniqueEntityArray<N, T>` -> `UniqueEntityEquivalentArray<T, N>`
#18555 improved syntax for required components.
However some code was a bit redundant after the new parsing and struct
initializing would not give proper errors.
This PR fixes that.
---------
Co-authored-by: Tim Overbeek <oorbecktim@Tims-MacBook-Pro.local>
# Objective
Improve the parameter validation error message for
`Event(Reader|Writer|Mutator)`.
System parameters defined using `#[derive(SystemParam)]`, including the
parameters for events, currently propagate the validation errors from
their subparameters. The error includes the type of the failing
parameter, so the resulting error includes the type of the failing
subparameter instead of the derived parameter.
In particular, `EventReader<T>` will report an error from a
`Res<Events<T>>`, even though the user has no parameter of that type!
This is a follow-up to #18593.
## Solution
Have `#[derive]`d system parameters map errors during propagation so
that they report the outer parameter type.
To continue to provide context, add a field to
`SystemParamValidationError` that identifies the subparameter by name,
and is empty for non-`#[derive]`d parameters.
Allow them to override the failure message for individual parameters.
Use this to convert "Resource does not exist" to "Event not initialized"
for `Event(Reader|Writer|Mutator)`.
## Showcase
The validation error for a `EventReader<SomeEvent>` parameter when
`add_event` has not been called changes from:
Before:
```
Parameter `Res<Events<SomeEvent>>` failed validation: Resource does not exist
```
After
```
Parameter `EventReader<SomeEvent>::events` failed validation: Event not initialized
```
Extension of #18409.
I was updating a migration guide for hierarchy commands and realized
`insert_children` wasn't added to `EntityCommands`, only
`EntityWorldMut`.
This adds that and `insert_related` (basically just some
copy-and-pasting).
# Objective
In #17905 we swapped to a named field on `ChildOf` to help resolve
variable naming ambiguity of child vs parent (ex: `child_of.parent`
clearly reads as "I am accessing the parent of the child_of
relationship", whereas `child_of.0` is less clear).
Unfortunately this has the side effect of making initialization less
ideal. `ChildOf { parent }` reads just as well as `ChildOf(parent)`, but
`ChildOf { parent: root }` doesn't read nearly as well as
`ChildOf(root)`.
## Solution
Move back to `ChildOf(pub Entity)` but add a `child_of.parent()`
function and use it for all accesses. The downside here is that users
are no longer "forced" to access the parent field with `parent`
nomenclature, but I think this strikes the right balance.
Take a look at the diff. I think the results provide strong evidence for
this change. Initialization has the benefit of reading much better _and_
of taking up significantly less space, as many lines go from 3 to 1, and
we're cutting out a bunch of syntax in some cases.
Sadly I do think this should land in 0.16 as the cost of doing this
_after_ the relationships migration is high.
# Objective
Provide more useful errors when `World::run_system` and related methods
fail parameter validation.
Let callers determine whether the validation failure would have skipped
or failed the system.
Follow-up to #18541.
## Solution
Add a `SystemParamValidationError` value to the
`RunSystemError::InvalidParams` and
`RegisteredSystemError::InvalidParams` variants. That includes the
complete context of the parameter validation error, including the
`skipped` flag.
fixes#17478
# Objective
- Complete #17558.
- the `insert_children` method was previously removed, and as #17478
points out, needs to be added back.
## Solution
- Add a `OrderedRelationshipSourceCollection`, which allows sorting,
ordering, rearranging, etc of a `RelationshipSourceCollection`.
- Implement `insert_related`
- Implement `insert_children`
- Tidy up some docs while I'm here.
## Testing
@bjoernp116 set up a unit test, and I added a doc test to
`OrderedRelationshipSourceCollection`.
---------
Co-authored-by: bjoernp116 <bjoernpollen@gmail.com>
Co-authored-by: Dmytro Banin <banind@cs.washington.edu>
Co-authored-by: Talin <viridia@gmail.com>
# Objective
#18173 allows components to be queued without being fully registered.
But much of bevy's debug logging contained
`components.get_name(id).unwrap()`. However, this panics when the id is
queued. This PR fixes this, allowing names to be retrieved for debugging
purposes, etc, even while they're still queued.
## Solution
We change `ComponentInfo::descriptor` to be `Arc<ComponentDescriptor>`
instead of not arc'd. This lets us pass the descriptor around (as a name
or otherwise) as needed. The alternative would require some form of
`MappedRwLockReadGuard`, which is unstable, and would be terribly
blocking. Putting it in an arc also signifies that it doesn't change,
which is a nice signal to users. This does mean there's an extra pointer
dereference, but I don't think that's an issue here, as almost all paths
that use this are for debugging purposes or one-time set ups.
## Testing
Existing tests.
## Migration Guide
`Components::get_name` now returns `Option<Cow<'_, str>` instead of
`Option<&str>`. This is because it now returns results for queued
components. If that behavior is not desired, or you know the component
is not queued, you can use
`components.get_info().map(ComponentInfo::name)` instead.
Similarly, `ScheduleGraph::conflicts_to_string` now returns `impl
Iterator<Item = (String, String, Vec<Cow<str>>)>` instead of `impl
Iterator<Item = (String, String, Vec<&str>)>`. Because `Cow<str>` derefs
to `&str`, most use cases can remain unchanged.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
- Lots of nits, formatting, and rephrasing, with the goal of making
things more consistent.
- Fix outdated error handler explanation in `Commands` and
`EntityCommands` docs.
- Expand docs for system-related commands.
- Remove panic notes if the command only panics with the default error
handler.
- Update error handling notes for `try_` variants.
- Hide `prelude` import in most doctest examples, unless the example
uses something that people might not realize is in the prelude (like
`Name`).
- Remove a couple doctest examples that (in my opinion) didn't make
sense.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
Improve error messages for missing resources.
The default error handler currently prints the `Debug` representation of
the error type instead of `Display`. Most error types use
`#[derive(Debug)]`, resulting in a dump of the structure, but will have
a user-friendly message for `Display`.
Follow-up to #18593
## Solution
Change the default error handler to use `Display` instead of `Debug`.
Change `BevyError` to include the backtrace in the `Display` format in
addition to `Debug` so that it is still included.
## Showcase
Before:
```
Encountered an error in system `system_name`: SystemParamValidationError { skipped: false, message: "Resource does not exist", param: "bevy_ecs::change_detection::Res<app_name::ResourceType>" }
Encountered an error in system `other_system_name`: "String message with\nmultiple lines."
```
After
```
Encountered an error in system `system_name`: Parameter `Res<ResourceType>` failed validation: Resource does not exist
Encountered an error in system `other_system_name`: String message with
multiple lines.
```
# Objective
- There's been several changes to `Query` for this release cycle, and
`Query`'s top-level documentation has gotten slightly out-of-date.
- Alternative to #18615.
## Solution
- Edit `Query`'s docs for consistency, clarity, and correctness.
- Make sure to group `get()` and `get_many()` together instead of
`single()` and `get_many()`, to enforce the distinction from
https://github.com/bevyengine/bevy/pull/18615#issuecomment-2764355672.
- Reformat doc tests so they would be readable if extracted into their
own file. (Which mainly involves adding more spacing.)
- Move link definitions to be nearer where they are used.
- Fix the tables so they are up-to-date and correctly escape square
brackets `\[ \]`.
## Testing
I ran `cargo doc -p bevy_ecs --no-deps` to view the docs and `cargo test
-p bevy_ecs --doc` to test the doc comments.
## Reviewing
The diff is difficult to read, so I don't recommend _just_ looking at
that. Instead, run `cargo doc -p bevy_ecs --no-deps` locally and read
through the new version. It should theoretically read smoother with less
super-technical jargon. :)
## Follow-up
I want to go through some of `Query`'s methods, such as `single()`,
`get()`, and `get_many()`, but I'll leave that for another PR.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
Fixes#9367.
Yet another follow-up to #16547.
These traits were initially based on `Borrow<Entity>` because that trait
was what they were replacing, and it felt close enough in meaning.
However, they ultimately don't quite match: `borrow` always returns
references, whereas `EntityBorrow` always returns a plain `Entity`.
Additionally, `EntityBorrow` can imply that we are borrowing an `Entity`
from the ECS, which is not what it does.
Due to its safety contract, `TrustedEntityBorrow` is important an
important and widely used trait for `EntitySet` functionality.
In contrast, the safe `EntityBorrow` does not see much use, because even
outside of `EntitySet`-related functionality, it is a better idea to
accept `TrustedEntityBorrow` over `EntityBorrow`.
Furthermore, as #9367 points out, abstracting over returning `Entity`
from pointers/structs that contain it can skip some ergonomic friction.
On top of that, there are aspects of #18319 and #18408 that are relevant
to naming:
We've run into the issue that relying on a type default can switch
generic order. This is livable in some contexts, but unacceptable in
others.
To remedy that, we'd need to switch to a type alias approach:
The "defaulted" `Entity` case becomes a
`UniqueEntity*`/`Entity*Map`/`Entity*Set` alias, and the base type
receives a more general name. `TrustedEntityBorrow` does not mesh
clearly with sensible base type names.
## Solution
Replace any `EntityBorrow` bounds with `TrustedEntityBorrow`.
+
Rename them as such:
`EntityBorrow` -> `ContainsEntity`
`TrustedEntityBorrow` -> `EntityEquivalent`
For `EntityBorrow` we produce a change in meaning; We designate it for
types that aren't necessarily strict wrappers around `Entity` or some
pointer to `Entity`, but rather any of the myriad of types that contain
a single associated `Entity`.
This pattern can already be seen in the common `entity`/`id` methods
across the engine.
We do not mean for `ContainsEntity` to be a trait that abstracts input
API (like how `AsRef<T>` is often used, f.e.), because eliding
`entity()` would be too implicit in the general case.
We prefix "Contains" to match the intuition of a struct with an `Entity`
field, like some contain a `length` or `capacity`.
It gives the impression of structure, which avoids the implication of a
relationship to the `ECS`.
`HasEntity` f.e. could be interpreted as "a currently live entity",
As an input trait for APIs like #9367 envisioned, `TrustedEntityBorrow`
is a better fit, because it *does* restrict itself to strict wrappers
and pointers. Which is why we replace any
`EntityBorrow`/`ContainsEntity` bounds with
`TrustedEntityBorrow`/`EntityEquivalent`.
Here, the name `EntityEquivalent` is a lot closer to its actual meaning,
which is "A type that is both equivalent to an `Entity`, and forms the
same total order when compared".
Prior art for this is the
[`Equivalent`](https://docs.rs/hashbrown/latest/hashbrown/trait.Equivalent.html)
trait in `hashbrown`, which utilizes both `Borrow` and `Eq` for its one
blanket impl!
Given that we lose the `Borrow` moniker, and `Equivalent` can carry
various meanings, we expand on the safety comment of `EntityEquivalent`
somewhat. That should help prevent the confusion we saw in
[#18408](https://github.com/bevyengine/bevy/pull/18408#issuecomment-2742094176).
The new name meshes a lot better with the type aliasing approach in
#18408, by aligning with the base name `EntityEquivalentHashMap`.
For a consistent scheme among all set types, we can use this scheme for
the `UniqueEntity*` wrapper types as well!
This allows us to undo the switched generic order that was introduced to
`UniqueEntityArray` by its `Entity` default.
Even without the type aliases, I think these renames are worth doing!
## Migration Guide
Any use of `EntityBorrow` becomes `ContainsEntity`.
Any use of `TrustedEntityBorrow` becomes `EntityEquivalent`.
# Objective
Unlike for their helper typers, the import paths for
`unique_array::UniqueEntityArray`, `unique_slice::UniqueEntitySlice`,
`unique_vec::UniqueEntityVec`, `hash_set::EntityHashSet`,
`hash_map::EntityHashMap`, `index_set::EntityIndexSet`,
`index_map::EntityIndexMap` are quite redundant.
When looking at the structure of `hashbrown`, we can also see that while
both `HashSet` and `HashMap` have their own modules, the main types
themselves are re-exported to the crate level.
## Solution
Re-export the types in their shared `entity` parent module, and simplify
the imports where they're used.
