# Objective
Help users discover how to use `Option<T>` and `When<T>` to handle
failing parameters.
## Solution
Have the error message for a failed parameter mention that `Option<T>`
and `When<T>` can be used to handle the failure.
## Showcase
```
Encountered an error in system `system_name`: Parameter `Res<ResourceType>` failed validation: Resource does not exist
If this is an expected state, wrap the parameter in `Option<T>` and handle `None` when it happens, or wrap the parameter in `When<T>` to skip the system when it happens.
```
# Objective
- Enable hot patching systems with subsecond
- Fixes#19296
## Solution
- First commit is the naive thin layer
- Second commit only check the jump table when the code is hot patched
instead of on every system execution
- Depends on https://github.com/DioxusLabs/dioxus/pull/4153 for a nicer
API, but could be done without
- Everything in second commit is feature gated, it has no impact when
the feature is not enabled
## Testing
- Check dependencies without the feature enabled: nothing dioxus in tree
- Run the new example: text and color can be changed
---------
Co-authored-by: Jan Hohenheim <jan@hohenheim.ch>
Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
# Objective
- Part 1 of #19454 .
- Split from PR #18860(authored by @notmd) for better review and limit
implementation impact. so all credit for this work belongs to @notmd .
## Solution
- Trigger `ArchetypeCreated ` when new archetype is createed
---------
Co-authored-by: mgi388 <135186256+mgi388@users.noreply.github.com>
# Objective
`Populated`, a loose wrapper around `Query`, does not implement
`IntoIterator`, requiring either a deref or `into_inner()` call to
access the `Query` and iterate over that.
## Solution
This pr implements `IntoIterator` for `Populated`, `&Populated`, and
`&mut Populated`, each of which forwards the call to the inner `Query`.
This allows the `Populated` to be used directly for any API that takes
an `impl IntoIterator`.
## Testing
`cargo test` was run on the `bevy_ecs` crate
```
test result: ok. 390 passed; 0 failed; 2 ignored; 0 measured; 0 filtered out; finished in 46.38s
```
# Objective
This is the first step of #19430 and is a follow up for #19132.
Now that `ArchetypeRow` has a niche, we can use `Option` instead of
needing `INVALID` everywhere.
This was especially concerning since `INVALID` *really was valid!*
Using options here made the code clearer and more data-driven.
## Solution
Replace all uses of `INVALID` entity locations (and archetype/table
rows) with `None`.
## Testing
CI
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fix#19324
## Solution
`EntityCloner` replaces required components when filtering. This is
unexpected when comparing with the way the rest of bevy handles required
components. This PR separates required components from explicit
components when filtering in `EntityClonerBuilder`.
## Testing
Added a regression test for this case.
# Objective
Fixes https://github.com/bevyengine/bevy/issues/17933
## Solution
Correct "value has changed'" in docs to "value has been added or mutably
dereferenced", with a note for emphasis copied from the docs for
Changed.
## Testing
-
# Objective
Recently the `u32` `Entity::generation` was replaced with the new
`EntityGeneration` in #19121.
This made meanings a lot more clear, and prevented accidental misuse.
One common misuse was assuming that `u32`s that were greater than others
came after those others.
Wrapping makes this assumption false.
When `EntityGeneration` was created, it retained the `u32` ordering,
which was useless at best and wrong at worst.
This pr fixes the ordering implementation, so new generations are
greater than older generations.
Some users were already accounting for this ordering issue (which was
still present in 0.16 and before) by manually accessing the `u32`
representation. This made migrating difficult for avian physics; see
[here](https://discord.com/channels/691052431525675048/749335865876021248/1377431569228103780).
I am generally of the opinion that this type should be kept opaque to
prevent accidental misuse.
As we find issues like this, the functionality should be added to
`EntityGeneration` directly.
## Solution
Fix the ordering implementation through `Ord`.
Alternatively, we could keep `Ord` the same and make a `cmp_age` method,
but I think this is better, even though sorting entity ids may be
*marginally* slower now (but more correct). This is a tradeoff.
## Testing
I improved documentation for aliasing and ordering, adding some doc
tests.
# Objective
There are several uninlined format args (seems to be in more formatting
macros and in more crates) that are not detected on stable, but are on
nightly.
## Solution
Fix them.
# Objective
#19047 added an `MaybeUninit` field to `EntityMeta`, but did not
guarantee that it will be initialized before access:
```rust
let mut world = World::new();
let id = world.entities().reserve_entity();
world.flush();
world.entity(id);
```
<details>
<summary>Miri Error</summary>
```
error: Undefined Behavior: using uninitialized data, but this operation requires initialized memory
--> /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1121:26
|
1121 | unsafe { meta.spawned_or_despawned.assume_init() }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
|
= help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
= help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
= note: BACKTRACE:
= note: inside closure at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1121:26: 1121:65
= note: inside `std::option::Option::<&bevy_ecs::entity::EntityMeta>::map::<bevy_ecs::entity::SpawnedOrDespawned, {closure@bevy_ecs::entity::Entities::entity_get_spawned_or_despawned::{closure#1}}>` at /home/vj/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/option.rs:1144:29: 1144:33
= note: inside `bevy_ecs::entity::Entities::entity_get_spawned_or_despawned` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1112:9: 1122:15
= note: inside closure at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1094:13: 1094:57
= note: inside `bevy_ecs::change_detection::MaybeLocation::<std::option::Option<&std::panic::Location<'_>>>::new_with_flattened::<{closure@bevy_ecs::entity::Entities::entity_get_spawned_or_despawned_by::{closure#0}}>` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/change_detection.rs:1371:20: 1371:24
= note: inside `bevy_ecs::entity::Entities::entity_get_spawned_or_despawned_by` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1093:9: 1096:11
= note: inside `bevy_ecs::entity::Entities::entity_does_not_exist_error_details` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1163:23: 1163:70
= note: inside `bevy_ecs::entity::EntityDoesNotExistError::new` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/entity/mod.rs:1182:22: 1182:74
= note: inside `bevy_ecs::world::unsafe_world_cell::UnsafeWorldCell::<'_>::get_entity` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/world/unsafe_world_cell.rs:368:20: 368:73
= note: inside `<bevy_ecs::entity::Entity as bevy_ecs::world::WorldEntityFetch>::fetch_ref` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/world/entity_fetch.rs:207:21: 207:42
= note: inside `bevy_ecs::world::World::get_entity::<bevy_ecs::entity::Entity>` at /home/vj/workspace/rust/bevy/crates/bevy_ecs/src/world/mod.rs:911:18: 911:42
note: inside `main`
--> src/main.rs:12:15
|
12 | world.entity(id);
|
```
</details>
## Solution
- remove the existing `MaybeUninit` in `EntityMeta.spawned_or_despawned`
- initialize during flush. This is not needed for soundness, but not
doing this means we can't return a sensible location/tick for flushed
entities.
## Testing
Test via the snippet above (also added equivalent test).
---------
Co-authored-by: urben1680 <55257931+urben1680@users.noreply.github.com>
# Objective
Fixes#18905
## Solution
`world.commands().entity(target_entity).queue(command)` calls
`commands.with_entity` without an error handler, instead queue on
`Commands` with an error handler
## Testing
Added unit test
Co-authored-by: Heart <>
# Objective
Remove `ArchetypeComponentId` and `archetype_component_access`.
Following #16885, they are no longer used by the engine, so we can stop
spending time calculating them or space storing them.
## Solution
Remove `ArchetypeComponentId` and everything that touches it.
The `System::update_archetype_component_access` method no longer needs
to update `archetype_component_access`. We do still need to update query
caches, but we no longer need to do so *before* running the system. We'd
have to touch every caller anyway if we gave the method a better name,
so just remove `System::update_archetype_component_access` and
`SystemParam::new_archetype` entirely, and update the query cache in
`Query::get_param`.
The `Single` and `Populated` params also need their query caches updated
in `SystemParam::validate_param`, so change `validate_param` to take
`&mut Self::State` instead of `&Self::State`.
# Objective
- move SyncCell and SyncUnsafeCell to bevy_platform
## Solution
- move SyncCell and SyncUnsafeCell to bevy_platform
## Testing
- cargo clippy works
Fixes#19081.
Simply created a duplicate of the existing `insert_if_new` test, but
using sparse sets.
## Testing:
The test passes on main, but fails if #19059 is reverted.
# Objective
Fix some grammatical errors: it's -> its
Not the most useful commit in the world, but I saw a couple of these and
decided to fix the lot.
## Solution
-
## Testing
-
# Objective
Fix https://github.com/bevyengine/bevy/issues/13390
## Solution
The second parameter of the remove_reflect function is called
component_type_name in ReflectCommandExt but component_type_path in the
implementation for EntityCommands. Use component_type_path in both
places.
## Testing
None
# Objective
Fixes#18790.
Simpler alternative to #19195.
## Solution
As suggested by @PixelDust22, simply avoid overwriting the pass if the
schedule already has auto sync points enabled.
Leave pass logic untouched.
It still is probably a bad idea to add systems/set configs before
changing the build settings, but that is not important as long there are
no more complex build passes.
## Testing
Added a test.
---------
Co-authored-by: Thierry Berger <contact@thierryberger.com>
# Objective
Since #18704 is done, we can track the length of unique entity row
collections with only a `u32` and identify an index within that
collection with only a `NonMaxU32`. This leaves an opportunity for
performance improvements.
## Solution
- Use `EntityRow` in sparse sets.
- Change table, entity, and query lengths to be `u32` instead of
`usize`.
- Keep `batching` module `usize` based since that is reused for events,
which may exceed `u32::MAX`.
- Change according `Range<usize>` to `Range<u32>`. This is more
efficient and helps justify safety.
- Change `ArchetypeRow` and `TableRow` to wrap `NonMaxU32` instead of
`u32`.
Justifying `NonMaxU32::new_unchecked` everywhere is predicated on this
safety comment in `Entities::set`: "`location` must be valid for the
entity at `index` or immediately made valid afterwards before handing
control to unknown code." This ensures no entity is in two table rows
for example. That fact is used to argue uniqueness of the entity rows in
each table, archetype, sparse set, query, etc. So if there's no
duplicates, and a maximum total entities of `u32::MAX` none of the
corresponding row ids / indexes can exceed `NonMaxU32`.
## Testing
CI
---------
Co-authored-by: Christian Hughes <9044780+ItsDoot@users.noreply.github.com>
# Objective
- Currently, the error span for `get_struct_field` when encountering an
enum or union points to the macro invocation, rather than the `enum` or
`union` token. It also doesn't mention which macro reported the error.
## Solution
- Report the correct error span
- Add parameter for passing in the name of the macro invocation
## Testing
Bevy compiles fine with this change
## Migration Guide
```rs
// before
let fields = get_struct_fields(&ast.data);
// after
let fields = get_struct_fields(&ast.data, "derive(Bundle)");
```
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Hiya!
# Objective
- Remove upcasting methods that are no longer necessary since Rust 1.86.
- Cleanup the interned label code.
## Notes
- I didn't try to remove the upcasting methods from `bevy_reflect`, as
there appears to be some complexity related to remote type reflection.
- There are likely some other upcasting methods floating around.
## Testing
I ran the `breakout` example to check that the hashing/eq
implementations of the labels are still correct.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
similar to https://github.com/bevyengine/bevy/pull/12030
# Objective
`bevy_mod_debugdump` uses the `SystemTypeSet::system_type` to look up
constrains like `(system_1, system_2.after(system_1))`. For that it
needs to find the type id in `schedule.graph().systems()`
Now with systems being wrapped in an `InfallibleSystemWrapper` this
association was no longer possible.
## Solution
By forwarding the type id in `InfallibleSystemWrapper`,
`bevy_mod_debugdump` can resolve the dependencies as before, and the
wrapper is an unnoticable implementation detail.
## Testing
- `cargo test -p bevy_ecs`
I'm not sure what exactly could break otherwise.
# Objective
Now that `bevy_platform::cfg` is merged, we can start tidying up
features. This PR starts with `bevy_utils`.
## Solution
- Removed `serde` and `critical-section` features (they were just
re-exports of `bevy_platform` anyway)
- Removed `std`, `alloc` features, relying on `bevy_platform::cfg` to
check for availability.
- Added `parallel` feature to provide access to the `Parallel` type.
- Moved the `HashMap` type aliases into `map.rs` for better
organisation.
## Testing
- CI
# Objective
Remove errant "a" from docs.
(I'm assuming that this sort of trivial fix is easy enough to merge that
it's worth doing, but let me know if you'd prefer me to not bother.)
# Objective
allow serialization / deserialization on the `ChildOf` entity, for
example in network usage.
my usage was for the bevy_replicon crate, to replicate `ChildOf`.
## Solution
same implementation of serde as other types in the bevy repo
---------
Co-authored-by: Hennadii Chernyshchyk <genaloner@gmail.com>
## Objective
Add documentation useful to users of `bevy_ecs` not also using `App`.
Fixes#19270.
## Solution
* Add explanation of labels to `Schedule` documentation.
* Add example of `derive(ScheduleLabel)` to `trait ScheduleLabel`.
* Add a third example to `Schedule` which demonstrates using a schedule
via label instead of owning it directly.
* Add further explanation and links to `World::add_schedule()`, and
`World::run_schedule()`.
## Testing
Reviewed generated documentation.
Please review this documentation carefully for correctness, as I have
little experience with `bevy_ecs` and I am adding this information
because it would have helped my own past confusion, but I may still be
wrong about how things should be done.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: theotherphil <phil.j.ellison@gmail.com>
# Objective
Fixes#19120
## Solution
Use the find and replace token feature in VSCode to replace all the
`Condition`s with `SystemCondition`s. Then look through all the
documentation with find and replace to replace all the `Condition`s
there.
## Testing
- Did you test these changes? If so, how?
Yes, used cargo clippy, cargo build and cargo test.
- Are there any parts that need more testing?
Nope
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
By compiling and running bevy
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
Shouldn't be, but Fedora Linux with KDE Wayland
# Objective
[see original
comment](https://github.com/bevyengine/bevy/pull/18801#issuecomment-2796981745)
> Alternately, could we store it on the World instead of a global? I
think we have a World nearby whenever we call default_error_handler().
That would avoid the need for atomics or locks, since we could do
ordinary reads and writes to the World.
Global error handlers don't actually need to be global – per world is
enough. This allows using different handlers for different worlds and
also removes the restrictions on changing the handler only once.
## Solution
Each `World` can now store its own error handler in a resource.
For convenience, you can also set the default error handler for an
`App`, which applies it to the worlds of all `SubApp`s. The old behavior
of only being able to set the error handler once is kept for apps.
We also don't need the `configurable_error_handler` feature anymore now.
## Testing
New/adjusted tests for failing schedule systems & observers.
---
## Showcase
```rust
App::new()
.set_error_handler(info)
…
```
`bevy_ecs` was meant to have the `States` and `SubStates`
`proc_macro_derive`s removed when the separate `bevy_state` [was
created](https://github.com/bevyengine/bevy/issues/13216) but they were
missed.
# Objective
Fixes#19130
## Solution
Fully quality `Result::Ok` so as to not accidentally invoke the anyhow
function of the same name
## Testing
Tested on this minimal repro with and without change.
main.rs
```rs
use anyhow::Ok;
use bevy::ecs::system::SystemParam;
#[derive(SystemParam)]
pub struct SomeParams;
fn main() {
}
```
Cargo.toml
```toml
[package]
name = "bevy-playground"
version = "0.1.0"
edition = "2024"
[dependencies]
anyhow = "1.0.98"
bevy = { path = "../bevy" }
```
# Objective
resolves#19092
## Solution
- remove the `.saturating_sub` from the index transformation
- add `.saturating_add` to the internal offset calculation
## Testing
- added regression test, confirming 0 index order + testing max bound
# Objective
In my own project I was encountering the issue to find out which
entities were spawned after applying commands. I began maintaining a
vector of all entities with generational information before and after
applying the command and diffing it. This was awfully complicated though
and has no constant complexity but grows with the number of entities.
## Solution
Looking at `EntyMeta` it seemed obvious to me that struct can track the
tick just as it does with `MaybeLocation`, updated from the same call.
After that it became almost a given to also introduce query data
`SpawnDetails` which offers methods to get the spawn tick and location,
and query filter `Spawned` that filters entities out that were not
spawned since the last run.
## Testing
I expanded a few tests and added new ones, though maybe I forgot a group
of tests that should be extended too. I basically searched `bevy_ecs`
for mentions of `Changed` and `Added` to see where the tests and docs
are.
Benchmarks of spawn/despawn can be found
[here](https://github.com/bevyengine/bevy/pull/19047#issuecomment-2852181374).
---
## Showcase
From the added docs, systems with equal complexity since the filter is
not archetypal:
```rs
fn system1(q: Query<Entity, Spawned>) {
for entity in &q { /* entity spawned */ }
}
fn system2(query: Query<(Entity, SpawnDetails)>) {
for (entity, spawned) in &query {
if spawned.is_spawned() { /* entity spawned */ }
}
}
```
`SpawnedDetails` has a few more methods:
```rs
fn print_spawn_details(query: Query<(Entity, SpawnDetails)>) {
for (entity, spawn_details) in &query {
if spawn_details.is_spawned() {
print!("new ");
}
println!(
"entity {:?} spawned at {:?} by {:?}",
entity,
spawn_details.spawned_at(),
spawn_details.spawned_by()
);
}
}
```
## Changes
No public api was changed, I only added to it. That is why I added no
migration guide.
- query data `SpawnDetails`
- query filter `Spawned`
- method `Entities::entity_get_spawned_or_despawned_at`
- method `EntityRef::spawned_at`
- method `EntityMut::spawned_at`
- method `EntityWorldMut::spawned_at`
- method `UnsafeEntityCell::spawned_at`
- method `FilteredEntityRef::spawned_at`
- method `FilteredEntityMut::spawned_at`
- method `EntityRefExcept::spawned_at`
- method `EntityMutExcept::spawned_at`
---------
Co-authored-by: Eagster <79881080+ElliottjPierce@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
This is a followup to #18704 . There's lots more followup work, but this
is the minimum to unblock #18670, etc.
This direction has been given the green light by Alice
[here](https://github.com/bevyengine/bevy/pull/18704#issuecomment-2853368129).
## Solution
I could have split this over multiple PRs, but I figured skipping
straight here would be easiest for everyone and would unblock things the
quickest.
This removes the now no longer needed `identifier` module and makes
`Entity::generation` go from `NonZeroU32` to `struct
EntityGeneration(u32)`.
## Testing
CI
---------
Co-authored-by: Mark Nokalt <marknokalt@live.com>
# Objective
There are two problems this aims to solve.
First, `Entity::index` is currently a `u32`. That means there are
`u32::MAX + 1` possible entities. Not only is that awkward, but it also
make `Entity` allocation more difficult. I discovered this while working
on remote entity reservation, but even on main, `Entities` doesn't
handle the `u32::MAX + 1` entity very well. It can not be batch reserved
because that iterator uses exclusive ranges, which has a maximum upper
bound of `u32::MAX - 1`. In other words, having `u32::MAX` as a valid
index can be thought of as a bug right now. We either need to make that
invalid (this PR), which makes Entity allocation cleaner and makes
remote reservation easier (because the length only needs to be u32
instead of u64, which, in atomics is a big deal), or we need to take
another pass at `Entities` to make it handle the `u32::MAX` index
properly.
Second, `TableRow`, `ArchetypeRow` and `EntityIndex` (a type alias for
u32) all have `u32` as the underlying type. That means using these as
the index type in a `SparseSet` uses 64 bits for the sparse list because
it stores `Option<IndexType>`. By using `NonMaxU32` here, we cut the
memory of that list in half. To my knowledge, `EntityIndex` is the only
thing that would really benefit from this niche. `TableRow` and
`ArchetypeRow` I think are not stored in an `Option` in bulk. But if
they ever are, this would help. Additionally this ensures
`TableRow::INVALID` and `ArchetypeRow::INVALID` never conflict with an
actual row, which in a nice bonus.
As a related note, if we do components as entities where `ComponentId`
becomes `Entity`, the the `SparseSet<ComponentId>` will see a similar
memory improvement too.
## Solution
Create a new type `EntityRow` that wraps `NonMaxU32`, similar to
`TableRow` and `ArchetypeRow`.
Change `Entity::index` to this type.
## Downsides
`NonMax` is implemented as a `NonZero` with a binary inversion. That
means accessing and storing the value takes one more instruction. I
don't think that's a big deal, but it's worth mentioning.
As a consequence, `to_bits` uses `transmute` to skip the inversion which
keeps it a nop. But that also means that ordering has now flipped. In
other words, higher indices are considered less than lower indices. I
don't think that's a problem, but it's also worth mentioning.
## Alternatives
We could keep the index as a u32 type and just document that `u32::MAX`
is invalid, modifying `Entities` to ensure it never gets handed out.
(But that's not enforced by the type system.) We could still take
advantage of the niche here in `ComponentSparseSet`. We'd just need some
unsafe manual conversions, which is probably fine, but opens up the
possibility for correctness problems later.
We could change `Entities` to fully support the `u32::MAX` index. (But
that makes `Entities` more complex and potentially slightly slower.)
## Testing
- CI
- A few tests were changed because they depend on different ordering and
`to_bits` values.
## Future Work
- It might be worth removing the niche on `Entity::generation` since
there is now a different niche.
- We could move `Entity::generation` into it's own type too for clarity.
- We should change `ComponentSparseSet` to take advantage of the new
niche. (This PR doesn't change that yet.)
- Consider removing or updating `Identifier`. This is only used for
`Entity`, so it might be worth combining since `Entity` is now more
unique.
---------
Co-authored-by: atlv <email@atlasdostal.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
Provide a generic `impl SystemParam for Option<P>` that uses system
parameter validation. This immediately gives useful impls for params
like `EventReader` and `GizmosState` that are defined in terms of `Res`.
It also allows third-party system parameters to be usable with `Option`,
which was previously impossible due to orphan rules.
Note that this is a behavior change for `Option<Single>`. It currently
fails validation if there are multiple matching entities, but with this
change it will pass validation and produce `None`.
Also provide an impl for `Result<P, SystemParamValidationError>`. This
allows systems to inspect the error if necessary, either for bubbling it
up or for checking the `skipped` flag.
Fixes#12634Fixes#14949
Related to #18516
## Solution
Add generic `SystemParam` impls for `Option` and `Result`, and remove
the impls for specific types.
Update documentation and `fallible_params` example with the new
semantics for `Option<Single>`.
# Objective
- Fixes a subset of https://github.com/bevyengine/bevy/issues/13735 by
making `EntityRef`, `EntityMut` + similar WorldQueries use the system's
change ticks when being created from within a system.
In particular, this means that `entity_ref.get_ref::<T>()` will use the
correct change ticks (the ones from the system), which matches the
behaviour of querying for `Ref<T>` directly in the system parameters.
## Solution
- Implements the solution described by
https://github.com/bevyengine/bevy/issues/13735#issuecomment-2652482918
which is to add change ticks to the `UnsafeEntityCell`
## Testing
- Added a unit test that is close to what users would encounter: before
this PR the `Added`/`Changed` filters on `Ref`s created from `EntityRef`
are incorrect.
# Objective
A fair few items were deprecated in 0.16. Let's delete them now that
we're in the 0.17 development cycle!
## Solution
- Deleted items marked deprecated in 0.16.
## Testing
- CI
---
## Notes
I'm making the assumption that _everything_ deprecated in 0.16 should be
removed in 0.17. That may be a false assumption in certain cases. Please
check the items to be removed to see if there are any exceptions we
should keep around for another cycle!
# Objective
In #18301, `NonSendMarker` was defined in such a way that it actually
implements `Send`. This isn't strictly a soundness issue, as its goal is
to be used as a `SystemParam`, and it _does_ appropriately mark system
access as `!Send`. It just seems odd that `NonSendMarker: Send`.
## Solution
- Made `NonSendMarker` wrap `PhantomData<*mut ()>`, which forces it to
be `!Send`.
## Testing
- CI
---
## Notes
This does mean constructing a `NonSendMarker` _value_ will require using
the `SystemParam` trait, but I think that's acceptable as the marker as
a value should be rarely required if at all.
# Objective
Fixes a part of #14274.
Bevy has an incredibly inconsistent naming convention for its system
sets, both internally and across the ecosystem.
<img alt="System sets in Bevy"
src="https://github.com/user-attachments/assets/d16e2027-793f-4ba4-9cc9-e780b14a5a1b"
width="450" />
*Names of public system set types in Bevy*
Most Bevy types use a naming of `FooSystem` or just `Foo`, but there are
also a few `FooSystems` and `FooSet` types. In ecosystem crates on the
other hand, `FooSet` is perhaps the most commonly used name in general.
Conventions being so wildly inconsistent can make it harder for users to
pick names for their own types, to search for system sets on docs.rs, or
to even discern which types *are* system sets.
To reign in the inconsistency a bit and help unify the ecosystem, it
would be good to establish a common recommended naming convention for
system sets in Bevy itself, similar to how plugins are commonly suffixed
with `Plugin` (ex: `TimePlugin`). By adopting a consistent naming
convention in first-party Bevy, we can softly nudge ecosystem crates to
follow suit (for types where it makes sense to do so).
Choosing a naming convention is also relevant now, as the [`bevy_cli`
recently adopted
lints](https://github.com/TheBevyFlock/bevy_cli/pull/345) to enforce
naming for plugins and system sets, and the recommended naming used for
system sets is still a bit open.
## Which Name To Use?
Now the contentious part: what naming convention should we actually
adopt?
This was discussed on the Bevy Discord at the end of last year, starting
[here](<https://discord.com/channels/691052431525675048/692572690833473578/1310659954683936789>).
`FooSet` and `FooSystems` were the clear favorites, with `FooSet` very
narrowly winning an unofficial poll. However, it seems to me like the
consensus was broadly moving towards `FooSystems` at the end and after
the poll, with Cart
([source](https://discord.com/channels/691052431525675048/692572690833473578/1311140204974706708))
and later Alice
([source](https://discord.com/channels/691052431525675048/692572690833473578/1311092530732859533))
and also me being in favor of it.
Let's do a quick pros and cons list! Of course these are just what I
thought of, so take it with a grain of salt.
`FooSet`:
- Pro: Nice and short!
- Pro: Used by many ecosystem crates.
- Pro: The `Set` suffix comes directly from the trait name `SystemSet`.
- Pro: Pairs nicely with existing APIs like `in_set` and
`configure_sets`.
- Con: `Set` by itself doesn't actually indicate that it's related to
systems *at all*, apart from the implemented trait. A set of what?
- Con: Is `FooSet` a set of `Foo`s or a system set related to `Foo`? Ex:
`ContactSet`, `MeshSet`, `EnemySet`...
`FooSystems`:
- Pro: Very clearly indicates that the type represents a collection of
systems. The actual core concept, system(s), is in the name.
- Pro: Parallels nicely with `FooPlugins` for plugin groups.
- Pro: Low risk of conflicts with other names or misunderstandings about
what the type is.
- Pro: In most cases, reads *very* nicely and clearly. Ex:
`PhysicsSystems` and `AnimationSystems` as opposed to `PhysicsSet` and
`AnimationSet`.
- Pro: Easy to search for on docs.rs.
- Con: Usually results in longer names.
- Con: Not yet as widely used.
Really the big problem with `FooSet` is that it doesn't actually
describe what it is. It describes what *kind of thing* it is (a set of
something), but not *what it is a set of*, unless you know the type or
check its docs or implemented traits. `FooSystems` on the other hand is
much more self-descriptive in this regard, at the cost of being a bit
longer to type.
Ultimately, in some ways it comes down to preference and how you think
of system sets. Personally, I was originally in favor of `FooSet`, but
have been increasingly on the side of `FooSystems`, especially after
seeing what the new names would actually look like in Avian and now
Bevy. I prefer it because it usually reads better, is much more clearly
related to groups of systems than `FooSet`, and overall *feels* more
correct and natural to me in the long term.
For these reasons, and because Alice and Cart also seemed to share a
preference for it when it was previously being discussed, I propose that
we adopt a `FooSystems` naming convention where applicable.
## Solution
Rename Bevy's system set types to use a consistent `FooSet` naming where
applicable.
- `AccessibilitySystem` → `AccessibilitySystems`
- `GizmoRenderSystem` → `GizmoRenderSystems`
- `PickSet` → `PickingSystems`
- `RunFixedMainLoopSystem` → `RunFixedMainLoopSystems`
- `TransformSystem` → `TransformSystems`
- `RemoteSet` → `RemoteSystems`
- `RenderSet` → `RenderSystems`
- `SpriteSystem` → `SpriteSystems`
- `StateTransitionSteps` → `StateTransitionSystems`
- `RenderUiSystem` → `RenderUiSystems`
- `UiSystem` → `UiSystems`
- `Animation` → `AnimationSystems`
- `AssetEvents` → `AssetEventSystems`
- `TrackAssets` → `AssetTrackingSystems`
- `UpdateGizmoMeshes` → `GizmoMeshSystems`
- `InputSystem` → `InputSystems`
- `InputFocusSet` → `InputFocusSystems`
- `ExtractMaterialsSet` → `MaterialExtractionSystems`
- `ExtractMeshesSet` → `MeshExtractionSystems`
- `RumbleSystem` → `RumbleSystems`
- `CameraUpdateSystem` → `CameraUpdateSystems`
- `ExtractAssetsSet` → `AssetExtractionSystems`
- `Update2dText` → `Text2dUpdateSystems`
- `TimeSystem` → `TimeSystems`
- `AudioPlaySet` → `AudioPlaybackSystems`
- `SendEvents` → `EventSenderSystems`
- `EventUpdates` → `EventUpdateSystems`
A lot of the names got slightly longer, but they are also a lot more
consistent, and in my opinion the majority of them read much better. For
a few of the names I took the liberty of rewording things a bit;
definitely open to any further naming improvements.
There are still also cases where the `FooSystems` naming doesn't really
make sense, and those I left alone. This primarily includes system sets
like `Interned<dyn SystemSet>`, `EnterSchedules<S>`, `ExitSchedules<S>`,
or `TransitionSchedules<S>`, where the type has some special purpose and
semantics.
## Todo
- [x] Should I keep all the old names as deprecated type aliases? I can
do this, but to avoid wasting work I'd prefer to first reach consensus
on whether these renames are even desired.
- [x] Migration guide
- [x] Release notes
# Objective
Originally [provided as a solution to a user's problem in
Discord](https://discord.com/channels/691052431525675048/1247654592838111302/1344431131277394042),
library authors might find the need to present user-registered systems
with system-specific data. Typically `Local<T>` is used for this type of
thing, but its not generally feasible or possible to configure/set the
underlying `T` data for locals. Alternatively, we can use `SystemInput`
to pass the data.
## Solution
- Added `IntoSystem::with_input`: Allows system-specific data to be
passed in explicitly.
- Added `IntoSystem::with_input_from`: Allows system-specific data to be
created at initialization time via `FromWorld`.
## Testing
Added two new tests, testing each of `with_input` and `with_input_from`.
# Objective
With the current `MapEntities` `impl`s, it is not possible to derive
things like this:
```rust
#[derive(Component)]
pub struct Inventory {
#[entities]
slots: Vec<Option<Entity>>,
}
```
This is because `MapEntities` is only implemented for `Vec<Entity>` &
`Option<Entity>`, and not arbitrary combinations of those.
It would be nice to also support those types.
## Solution
I replaced the `impl`s of the following types
- `Option<Entity>`: replaced with `Option<T>`
- `Vec<Entity>`: replaced with `Vec<T>`
- `HashSet<Entity, S>`: replaced with `HashSet<T, S>`
- `T` also had to be `Eq + core:#️⃣:Hash` here. **Not sure if this is
too restrictive?**
- `IndexSet<Entity, S>`: replaced with `IndexSet <T, S>`
- `T` also had to be `Eq + core:#️⃣:Hash` here. **Not sure if this is
too restrictive?**
- `BTreeSet<Entity>`: replaced with `BTreeSet<T>`
- `VecDeque<Entity>`: replaced with `VecDeque<T>`
- `SmallVec<A: smallvec::Array<Item = Entity>>`: replaced with
`SmallVec<A: smallvec::Array<Item = T>>`
(in all of the above, `T` is a generic type that implements
`MapEntities` (`Entity` being one of them).)
## Testing
I did not test any of this, but extended the `Component::map_entities`
doctest with an example usage of the newly supported types.
---
## Showcase
With these changes, this is now possible:
```rust
#[derive(Component)]
pub struct Inventory {
#[entities]
slots: Vec<Option<Entity>>,
}
```
# 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.
# Objective
Fixes#18515
After the recent changes to system param validation, the panic message
for a missing resource is currently:
```
Encountered an error in system `missing_resource_error::res_system`: SystemParamValidationError { skipped: false }
```
Add the parameter type name and a descriptive message, improving the
panic message to:
```
Encountered an error in system `missing_resource_error::res_system`: SystemParamValidationError { skipped: false, message: "Resource does not exist", param: "bevy_ecs::change_detection::Res<missing_resource_error::MissingResource>" }
```
## Solution
Add fields to `SystemParamValidationError` for error context. Include
the `type_name` of the param and a message.
Store them as `Cow<'static, str>` and only format them into a friendly
string in the `Display` impl. This lets us create errors using a
`&'static str` with no allocation or formatting, while still supporting
runtime `String` values if necessary.
Add a unit test that verifies the panic message.
## Future Work
If we change the default error handling to use `Display` instead of
`Debug`, and to use `ShortName` for the system name, the panic message
could be further improved to:
```
Encountered an error in system `res_system`: Parameter `Res<MissingResource>` failed validation: Resource does not exist
```
However, `BevyError` currently includes the backtrace in `Debug` but not
`Display`, and I didn't want to try to change that in this PR.
