# Objective
FilteredResource::get should return a Result instead of Option
Fixes#17480
---
## Migration Guide
Users will need to handle the different return type on
FilteredResource::get, FilteredResource::get_id,
FilteredResource::get_mut as it is now a Result not an Option.
# Objective
Continuation of #17449.
#17449 implemented the wrapper types around `IndexMap`/`Set` and co.,
however punted on the slice types.
They are needed to support creating `EntitySetIterator`s from their
slices, not just the base maps and sets.
## Solution
Add the wrappers, in the same vein as #17449 and #17589 before.
The `Index`/`IndexMut` implementations take up a lot of space, however
they cannot be merged because we'd then get overlaps.
They are simply named `Slice` to match the `indexmap` naming scheme, but
this means they cannot be differentiated properly until their modules
are made public, which is already a follow-up mentioned in #17954.
# Objective
Now that #13432 has been merged, it's important we update our reflected
types to properly opt into this feature. If we do not, then this could
cause issues for users downstream who want to make use of
reflection-based cloning.
## Solution
This PR is broken into 4 commits:
1. Add `#[reflect(Clone)]` on all types marked `#[reflect(opaque)]` that
are also `Clone`. This is mandatory as these types would otherwise cause
the cloning operation to fail for any type that contains it at any
depth.
2. Update the reflection example to suggest adding `#[reflect(Clone)]`
on opaque types.
3. Add `#[reflect(clone)]` attributes on all fields marked
`#[reflect(ignore)]` that are also `Clone`. This prevents the ignored
field from causing the cloning operation to fail.
Note that some of the types that contain these fields are also `Clone`,
and thus can be marked `#[reflect(Clone)]`. This makes the
`#[reflect(clone)]` attribute redundant. However, I think it's safer to
keep it marked in the case that the `Clone` impl/derive is ever removed.
I'm open to removing them, though, if people disagree.
4. Finally, I added `#[reflect(Clone)]` on all types that are also
`Clone`. While not strictly necessary, it enables us to reduce the
generated output since we can just call `Clone::clone` directly instead
of calling `PartialReflect::reflect_clone` on each variant/field. It
also means we benefit from any optimizations or customizations made in
the `Clone` impl, including directly dereferencing `Copy` values and
increasing reference counters.
Along with that change I also took the liberty of adding any missing
registrations that I saw could be applied to the type as well, such as
`Default`, `PartialEq`, and `Hash`. There were hundreds of these to
edit, though, so it's possible I missed quite a few.
That last commit is **_massive_**. There were nearly 700 types to
update. So it's recommended to review the first three before moving onto
that last one.
Additionally, I can break the last commit off into its own PR or into
smaller PRs, but I figured this would be the easiest way of doing it
(and in a timely manner since I unfortunately don't have as much time as
I used to for code contributions).
## Testing
You can test locally with a `cargo check`:
```
cargo check --workspace --all-features
```
# Objective
Currently experimenting with manually implementing
`Relationship`/`RelationshipTarget` to support associated edge data,
which means I need to replace the default hook implementations provided
by those traits. However, copying them over for editing revealed that
`UnsafeWorldCell::get_raw_command_queue` is `pub(crate)`, and I would
like to not have to clone the source collection, like the default impl.
So instead, I've taken to providing a safe abstraction for being able to
access entities and queue commands simultaneously.
## Solution
Added `World::entities_and_commands` and
`DeferredWorld::entities_and_commands`, which can be used like so:
```rust
let eid: Entity = /* ... */;
let (mut fetcher, mut commands) = world.entities_and_commands();
let emut = fetcher.get_mut(eid).unwrap();
commands.entity(eid).despawn();
```
## Testing
- Added a new test for each of the added functions.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Continuation to #16547 and #17954.
The `get_many` family are the last methods on `Query`/`QueryState` for
which we're still missing a `unique` version.
## Solution
Offer `get_many_unique`/`get_many_unique_mut` and
`get_many_unique_inner`!
Their implementation is the same as `get_many`, the difference lies in
their guaranteed-to-be unique inputs, meaning we never do any aliasing
checks.
To reduce confusion, we also rename `get_many_readonly` into
`get_many_inner` and the current `get_many_inner` into
`get_many_mut_inner` to clarify their purposes.
## Testing
Doc examples.
## Migration Guide
`get_many_inner` is now called `get_many_mut_inner`.
`get_many_readonly` is now called `get_many_inner`.
Registering dynamic bundles was not possible for the user yet.
It is alone not very useful though as there are no methods to clone,
move or remove components via a `BundleId`. This could be a follow-up
work if this PR is approved and such a third (besides `T: Bundle` and
`ComponentId`(s)) API for structural operation is desired. I certainly
would use a hypothetical `EntityClonerBuilder::allow_by_bundle_id`.
I personally still would like this register method because I have a
`Bundles`-like custom data structure and I would like to not reinvent
the wheel. Then instead of having boxed `ComponentId` slices in my
collection I could look up explicit and required components there.
For reference scroll up to the typed version right above the new one.
# Objective
Installment of the #16547 series.
The vast majority of uses for these types will be the `Entity` case, so
it makes sense for it to be the default.
## Solution
`UniqueEntityVec`, `UniqueEntitySlice`, `UniqueEntityArray` and their
helper iterator aliases now have `Entity` as a default.
Unfortunately, this means the the `T` parameter for `UniqueEntityArray`
now has to be ordered after the `N` constant, which breaks the
consistency to `[T; N]`.
Same with about a dozen iterator aliases that take some `P`/`F`
predicate/function parameter.
This should however be an ergonomic improvement in most cases, so we'll
just have to live with this inconsistency.
## Migration Guide
Switch type parameter order for the relevant wrapper types/aliases.
# Objective
#13432 added proper reflection-based cloning. This is a better method
than cloning via `clone_value` for reasons detailed in the description
of that PR. However, it may not be immediately apparent to users why one
should be used over the other, and what the gotchas of `clone_value`
are.
## Solution
This PR marks `PartialReflect::clone_value` as deprecated, with the
deprecation notice pointing users to `PartialReflect::reflect_clone`.
However, it also suggests using a new method introduced in this PR:
`PartialReflect::to_dynamic`.
`PartialReflect::to_dynamic` is essentially a renaming of
`PartialReflect::clone_value`. By naming it `to_dynamic`, we make it
very obvious that what's returned is a dynamic type. The one caveat to
this is that opaque types still use `reflect_clone` as they have no
corresponding dynamic type.
Along with changing the name, the method is now optional, and comes with
a default implementation that calls out to the respective reflection
subtrait method. This was done because there was really no reason to
require manual implementors provide a method that almost always calls
out to a known set of methods.
Lastly, to make this default implementation work, this PR also did a
similar thing with the `clone_dynamic ` methods on the reflection
subtraits. For example, `Struct::clone_dynamic` has been marked
deprecated and is superseded by `Struct::to_dynamic_struct`. This was
necessary to avoid the "multiple names in scope" issue.
### Open Questions
This PR maintains the original signature of `clone_value` on
`to_dynamic`. That is, it takes `&self` and returns `Box<dyn
PartialReflect>`.
However, in order for this to work, it introduces a panic if the value
is opaque and doesn't override the default `reflect_clone`
implementation.
One thing we could do to avoid the panic would be to make the conversion
fallible, either returning `Option<Box<dyn PartialReflect>>` or
`Result<Box<dyn PartialReflect>, ReflectCloneError>`.
This makes using the method a little more involved (i.e. users have to
either unwrap or handle the rare possibility of an error), but it would
set us up for a world where opaque types don't strictly need to be
`Clone`. Right now this bound is sort of implied by the fact that
`clone_value` is a required trait method, and the default behavior of
the macro is to use `Clone` for opaque types.
Alternatively, we could keep the signature but make the method required.
This maintains that implied bound where manual implementors must provide
some way of cloning the value (or YOLO it and just panic), but also
makes the API simpler to use.
Finally, we could just leave it with the panic. It's unlikely this would
occur in practice since our macro still requires `Clone` for opaque
types, and thus this would only ever be an issue if someone were to
manually implement `PartialReflect` without a valid `to_dynamic` or
`reflect_clone` method.
## Testing
You can test locally using the following command:
```
cargo test --package bevy_reflect --all-features
```
---
## Migration Guide
`PartialReflect::clone_value` is being deprecated. Instead, use
`PartialReflect::to_dynamic` if wanting to create a new dynamic instance
of the reflected value. Alternatively, use
`PartialReflect::reflect_clone` to attempt to create a true clone of the
underlying value.
Similarly, the following methods have been deprecated and should be
replaced with these alternatives:
- `Array::clone_dynamic` → `Array::to_dynamic_array`
- `Enum::clone_dynamic` → `Enum::to_dynamic_enum`
- `List::clone_dynamic` → `List::to_dynamic_list`
- `Map::clone_dynamic` → `Map::to_dynamic_map`
- `Set::clone_dynamic` → `Set::to_dynamic_set`
- `Struct::clone_dynamic` → `Struct::to_dynamic_struct`
- `Tuple::clone_dynamic` → `Tuple::to_dynamic_tuple`
- `TupleStruct::clone_dynamic` → `TupleStruct::to_dynamic_tuple_struct`
# Objective
While poking at https://github.com/bevyengine/bevy/issues/17272, I
noticed a few small things to clean up.
## Solution
- Improve the docs
- ~~move `SystemErrorContext` out of the `handler.rs` module: it's not
an error handler~~
# Objective
Prevents duplicate implementation between IntoSystemConfigs and
IntoSystemSetConfigs using a generic, adds a NodeType trait for more
config flexibility (opening the door to implement
https://github.com/bevyengine/bevy/issues/14195?).
## Solution
Followed writeup by @ItsDoot:
https://hackmd.io/@doot/rJeefFHc1x
Removes IntoSystemConfigs and IntoSystemSetConfigs, instead using
IntoNodeConfigs with generics.
## Testing
Pending
---
## Showcase
N/A
## Migration Guide
SystemSetConfigs -> NodeConfigs<InternedSystemSet>
SystemConfigs -> NodeConfigs<ScheduleSystem>
IntoSystemSetConfigs -> IntoNodeConfigs<InternedSystemSet, M>
IntoSystemConfigs -> IntoNodeConfigs<ScheduleSystem, M>
---------
Co-authored-by: Christian Hughes <9044780+ItsDoot@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
In updating examples to use the Improved Spawning API I got tripped up
on being able to spawn children with a Vec. I eventually figured out
that I could use `Children::spawn(SpawnIter(my_vec.into_iter()))` but
thought there might be a more ergonomic way to approach it. After
tinkering with it for a while I came up with the implementation here. It
allows authors to use `Children::spawn(my_vec)` as an equivalent
implementation.
## Solution
- Implements `<R: Relationship, B: Bundle SpawnableList<R> for Vec<B>`
- uses `alloc::vec::Vec` for compatibility with `no_std` (`std::Vec`
also inherits implementations against the `alloc::vec::Vec` because std
is a re-export of the alloc struct, thanks @bushrat011899 for the info
on this!)
## Testing
- Did you test these changes? If so, how?
- Opened the examples before and after and verified the same behavior
was observed. I did this on Ubuntu 24.04.2 LTS using `--features
wayland`.
- Are there any parts that need more testing?
- Other OS's and features can't hurt, but this is such a small change it
shouldn't be a problem.
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- Run the examples yourself with and without these changes.
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
- see above
## Showcase
n/a
## Migration Guide
- Optional: you may use the new API to spawn `Vec`s of `Bundle` instead
of using the `SpawnIter` approach.
# Objective
- Prevent usage of `println!`, `eprintln!` and the like because they
require `std`
- Fixes#17446
## Solution
- Enable the `print_stdout` and `print_stderr` clippy lints
- Replace all `println!` and `eprintln!` occurrences with `log::*` where
applicable or alternatively ignore the warnings
## Testing
- Run `cargo clippy --workspace` to ensure that there are no warnings
relating to printing to `stdout` or `stderr`
# Objective
Part of the #16547 series.
The entity wrapper types often have some associated types an aliases
with them that cannot be re-exported into an outer module together.
Some helper types are best used with part of their path:
`bevy::ecs::entity::index_set::Slice` as `index_set::Slice`.
This has already been done for `entity::hash_set` and
`entity::hash_map`.
## Solution
Publicize the `index_set`, `index_map`, `unique_vec`, `unique_slice`,
and `unique_array` modules.
## Migration Guide
Any mention or import of types in the affected modules have to add the
respective module name to the import path.
F.e.:
`bevy::ecs::entity::EntityIndexSet` ->
`bevy::ecs::entity::index_set::EntityIndexSet`
# Objective
While redoing #18058 I needed `RelationshipSourceCollection` (henceforth
referred to as the **Trait**) to implement `clear` so I added it.
## Solution
Add the `clear` method to the **Trait**.
Also make `add` and `remove` report if they succeeded.
## Testing
Eyeballs
---
## Showcase
The `RelationshipSourceCollection` trait now reports if adding or
removing an entity from it was successful.
It also not contains the `clear` method so you can easily clear the
collection in generic contexts.
## Changes
EDITED by Alice: We should get this into 0.16, so no migration guide
needed.
The `RelationshipSourceCollection` methods `add` and `remove` now need
to return a boolean indicating if they were successful (adding a entity
to a set that already contains it counts as failure). Additionally the
`clear` method has been added to support clearing the collection in
generic contexts.
# Objective
I was recently exploreing `Entities` and stumbled on something strange.
`Entities::len` (the field) has the comment `Stores the number of free
entities for [`len`](Entities::len)`, refering to the method. But that
method says `The count of currently allocated entities.` Looking at the
code, the field's comment is wrong, and the public `len()` is correct.
Phew!
## Solution
So, I was just going to fix the comment, so it didn't confuse anyone
else, but as it turns out, we can just remove the field entirely. As a
bonus, this saves some book keeping work too. We can just calculate it
on the fly.
Also, add additional length methods and documentation for completeness.
These new length methods might be useful debug tools in the future.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
Make component registration faster. This is a tinny, almost petty PR,
but it led to roughly 10% faster registration, according to my
benchmarks in #17871.
Up to y'all if we do this or not. It is completely unnecessary, but its
such low hanging fruit that I wanted to put it out there.
## Solution
Instead of cloning a `HashSet`, collect it into a `SmallVec`. Since this
is empty for many components, this saves a lot of allocation and hashing
work.
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
This is an alternative to #17871 and #17701 for tracking issue #18155.
This thanks to @maniwani for help with this design.
The goal is to enable component ids to be reserved from multiple threads
concurrently and with only `&World`. This contributes to assets as
entities, read-only query and system parameter initialization, etc.
## What's wrong with #17871 ?
In #17871, I used my proposed staging utilities to allow *fully*
registering components from any thread concurrently with only
`&Components`. However, if we want to pursue components as entities
(which is desirable for a great many reasons. See
[here](https://discord.com/channels/691052431525675048/692572690833473578/1346499196655505534)
on discord), this staging isn't going to work. After all, if registering
a component requires spawning an entity, and spawning an entity requires
`&mut World`, it is impossible to register a component fully with only
`&World`.
## Solution
But what if we don't have to register it all the way? What if it's
enough to just know the `ComponentId` it will have once it is registered
and to queue it to be registered at a later time? Spoiler alert: That is
all we need for these features.
Here's the basic design:
Queue a registration:
1. Check if it has already been registered.
2. Check if it has already been queued.
3. Reserve a `ComponentId`.
4. Queue the registration at that id.
Direct (normal) registration:
1. Check if this registration has been queued.
2. If it has, use the queued registration instead.
3. Otherwise, proceed like normal.
Appllying the queue:
1. Pop queued items off one by one.
2. Register them directly.
One other change:
The whole point of this design over #17871 is to facilitate coupling
component registration with the World. To ensure that this would fully
work with that, I went ahead and moved the `ComponentId` generator onto
the world itself. That stemmed a couple of minor organizational changes
(see migration guide). As we do components as entities, we will replace
this generator with `Entities`, which lives on `World` too. Doing this
move early let me verify the design and will reduce migration headaches
in the future. If components as entities is as close as I think it is, I
don't think splitting this up into different PRs is worth it. If it is
not as close as it is, it might make sense to still do #17871 in the
meantime (see the risks section). I'll leave it up to y'all what we end
up doing though.
## Risks and Testing
The biggest downside of this compared to #17871 is that now we have to
deal with correct but invalid `ComponentId`s. They are invalid because
the component still isn't registered, but they are correct because, once
registered, the component will have exactly that id.
However, the only time this becomes a problem is if some code violates
safety rules by queuing a registration and using the returned id as if
it was valid. As this is a new feature though, nothing in Bevy does
this, so no new tests were added for it. When we do use it, I left
detailed docs to help mitigate issues here, and we can test those
usages. Ex: we will want some tests on using queries initialized from
queued registrations.
## Migration Guide
Component registration can now be queued with only `&World`. To
facilitate this, a few APIs needed to be moved around.
The following functions have moved from `Components` to
`ComponentsRegistrator`:
- `register_component`
- `register_component_with_descriptor`
- `register_resource_with_descriptor`
- `register_non_send`
- `register_resource`
- `register_required_components_manual`
Accordingly, functions in `Bundle` and `Component` now take
`ComponentsRegistrator` instead of `Components`.
You can obtain `ComponentsRegistrator` from the new
`World::components_registrator`.
You can obtain `ComponentsQueuedRegistrator` from the new
`World::components_queue`, and use it to stage component registration if
desired.
# Open Question
Can we verify that it is enough to queue registration with `&World`? I
don't think it would be too difficult to package this up into a
`Arc<MyComponentsManager>` type thing if we need to, but keeping this on
`&World` certainly simplifies things. If we do need the `Arc`, we'll
need to look into partitioning `Entities` for components as entities, so
we can keep most of the allocation fast on `World` and only keep a
smaller partition in the `Arc`. I'd love an SME on assets as entities to
shed some light on this.
---------
Co-authored-by: andriyDev <andriydzikh@gmail.com>
# Objective
Fixes#18030
## Solution
When running a one-shot system, requeue the system's command queue onto
the world's command queue, then execute the later.
If running the entire command queue of the world is undesired, I could
add a new method to `RawCommandQueue` to only apply part of it.
## Testing
See the new test.
---
## Showcase
```rust
#[derive(Resource)]
pub struct Test {
id: SystemId,
counter: u32,
}
let mut world = World::new();
let id = world.register_system(|mut commands: Commands, mut test: ResMut<Test>| {
print!("{:?} ", test.counter);
test.counter -= 1;
if test.counter > 0 {
commands.run_system(test.id);
}
});
world.insert_resource(Test { id, counter: 5 });
world.run_system(id).unwrap();
```
```
5 4 3 2 1
```
# Objective
I found a bug while working on #17871. When required components are
registered, ones that are more specific (smaller inheritance depth) are
preferred to others. So, if a ComponentA is already required, but it is
registered as required again, it will be updated if and only if the new
requirement has a smaller inheritance depth (is more specific). However,
this logic was not reflected in merging `RequriedComponents`s together.
Hence, for complicated requirement trees, the wrong initializer could be
used.
## Solution
Re-write merging to work by extending the collection via
`require_dynamic` instead of blindly combining the inner storage.
## Testing
I created this test to ensure this bug doesn't creep back in. This test
fails on main, but passes on this branch.
```rs
#[test]
fn required_components_inheritance_depth_bias() {
#[derive(Component, PartialEq, Eq, Clone, Copy, Debug)]
struct MyRequired(bool);
#[derive(Component, Default)]
#[require(MyRequired(|| MyRequired(false)))]
struct MiddleMan;
#[derive(Component, Default)]
#[require(MiddleMan)]
struct ConflictingRequire;
#[derive(Component, Default)]
#[require(MyRequired(|| MyRequired(true)))]
struct MyComponent;
let mut world = World::new();
let order_a = world
.spawn((ConflictingRequire, MyComponent))
.get::<MyRequired>()
.cloned();
let order_b = world
.spawn((MyComponent, ConflictingRequire))
.get::<MyRequired>()
.cloned();
assert_eq!(order_a, Some(MyRequired(true)));
assert_eq!(order_b, Some(MyRequired(true)));
}
```
Note that when the inheritance depth is 0 (Like if there were no middle
man above), the order of the components in the bundle still matters.
## Migration Guide
`RequiredComponents::register_dynamic` has been changed to
`RequiredComponents::register_dynamic_with`.
Old:
```rust
required_components.register_dynamic(
component_id,
component_constructor.clone(),
requirement_inheritance_depth,
);
```
New:
```rust
required_components.register_dynamic_with(
component_id,
requirement_inheritance_depth,
|| component_constructor.clone(),
);
```
This can prevent unnecessary cloning.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Co-authored-by: Joona Aalto <jondolf.dev@gmail.com>
# Objective
Fix unsound lifetimes in `Query::join` and `Query::join_filtered`.
The joined query allowed access from either input query, but it only
took the `'world` lifetime from `self`, not from `other`. This meant
that after the borrow of `other` ended, the joined query would unsoundly
alias `other`.
## Solution
Change the lifetimes on `join` and `join_filtered` to require mutable
borrows of the *same* lifetime for the input queries. This ensures both
input queries are borrowed for the full lifetime of the joined query.
Change `join_inner` to take `other` by value instead of reference so
that the returned query is still usable without needing to borrow from a
local variable.
## Testing
Added a compile-fail test.
# Objective
Make `bevy_error_panic_hook` threadsafe. As it relies on a global
variable, it fails when multiple threads panic.
## Solution
Switch from a global variable for storing whether an error message was
printed to a thread-local one.
`thread_local` is in `std`; the `backtrace` already relies on `std`
APIs. It didn't depend on the `std` feature though, so I've added that.
I've also put `bevy_error_panic_hook` behind the `backtrace` feature,
since it relies on the thread local variable, which fixes#18231.
## Testing
The following now loops instead of crashing:
```rust
std:🧵:scope(|s| {
use bevy_ecs::error::*;
#[derive(Debug)]
struct E;
impl std::fmt::Display for E {
fn fmt(&self, _: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
todo!()
}
}
impl std::error::Error for E {}
std::panic::set_hook(Box::new(bevy_error_panic_hook(|_| {
unreachable!();
})));
for _ in 0..2 {
s.spawn(|| {
loop {
let _ = std::panic::catch_unwind(|| {
panic!("{:?}", BevyError::from(E));
});
}
});
}
});
```
# Objective
- Allow `Query` methods such as `Query::get` to have their error
short-circuited using `?` in systems using Bevy's `Error` type
## Solution
- Removed `UnsafeWorldCell<'w>` from `QueryEntityError` and instead
store `ArchetypeId` (the information the error formatter was extracting
anyway).
- Replaced trait implementations with derives now that the type is
plain-old-data.
## Testing
- CI
---
## Migration Guide
- `QueryEntityError::QueryDoesNotMatch.1` is of type `ArchetypeId`
instead of `UnsafeWorldCell`. It is up to the caller to obtain an
`UnsafeWorldCell` now.
- `QueryEntityError` no longer has a lifetime parameter, remove it from
type signatures where required.
## Notes
This was discussed on Discord and accepted by Cart as the desirable path
forward in [this
message](https://discord.com/channels/691052431525675048/749335865876021248/1346611950527713310).
Scroll up from this point for context.
---------
Co-authored-by: SpecificProtagonist <30270112+SpecificProtagonist@users.noreply.github.com>
also updates Relationship docs terminology
# Objective
- Contributes to #18111
## Solution
Updates Component docs with a new section linking to Relationship. Also
updates some Relationship terminology as I understand it.
## Testing
- Did you test these changes? If so, how?
- opened Docs, verified link
- Are there any parts that need more testing?
- I don't think so
- How can other people (reviewers) test your changes? Is there anything
specific they need to know?
- run `cargo doc --open` and check out Component and Relationship docs,
verify their correctness
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?
- I think this is n/a but I ran the doc command on Ubuntu 24.04.2 LTS
---
## Showcase
## Migration Guide
n/a
# Objective
- Fixes#15460 (will open new issues for further `no_std` efforts)
- Supersedes #17715
## Solution
- Threaded in new features as required
- Made certain crates optional but default enabled
- Removed `compile-check-no-std` from internal `ci` tool since GitHub CI
can now simply check `bevy` itself now
- Added CI task to check `bevy` on `thumbv6m-none-eabi` to ensure
`portable-atomic` support is still valid [^1]
[^1]: This may be controversial, since it could be interpreted as
implying Bevy will maintain support for `thumbv6m-none-eabi` going
forward. In reality, just like `x86_64-unknown-none`, this is a
[canary](https://en.wiktionary.org/wiki/canary_in_a_coal_mine) target to
make it clear when `portable-atomic` no longer works as intended (fixing
atomic support on atomically challenged platforms). If a PR comes
through and makes supporting this class of platforms impossible, then
this CI task can be removed. I however wager this won't be a problem.
## Testing
- CI
---
## Release Notes
Bevy now has support for `no_std` directly from the `bevy` crate.
Users can disable default features and enable a new `default_no_std`
feature instead, allowing `bevy` to be used in `no_std` applications and
libraries.
```toml
# Bevy for `no_std` platforms
bevy = { version = "0.16", default-features = false, features = ["default_no_std"] }
```
`default_no_std` enables certain required features, such as `libm` and
`critical-section`, and as many optional crates as possible (currently
just `bevy_state`). For atomically-challenged platforms such as the
Raspberry Pi Pico, `portable-atomic` will be used automatically.
For library authors, we recommend depending on `bevy` with
`default-features = false` to allow `std` and `no_std` users to both
depend on your crate. Here are some recommended features a library crate
may want to expose:
```toml
[features]
# Most users will be on a platform which has `std` and can use the more-powerful `async_executor`.
default = ["std", "async_executor"]
# Features for typical platforms.
std = ["bevy/std"]
async_executor = ["bevy/async_executor"]
# Features for `no_std` platforms.
libm = ["bevy/libm"]
critical-section = ["bevy/critical-section"]
[dependencies]
# We disable default features to ensure we don't accidentally enable `std` on `no_std` targets, for example.
bevy = { version = "0.16", default-features = false }
```
While this is verbose, it gives the maximum control to end-users to
decide how they wish to use Bevy on their platform.
We encourage library authors to experiment with `no_std` support. For
libraries relying exclusively on `bevy` and no other dependencies, it
may be as simple as adding `#![no_std]` to your `lib.rs` and exposing
features as above! Bevy can also provide many `std` types, such as
`HashMap`, `Mutex`, and `Instant` on all platforms. See
`bevy::platform_support` for details on what's available out of the box!
## Migration Guide
- If you were previously relying on `bevy` with default features
disabled, you may need to enable the `std` and `async_executor`
features.
- `bevy_reflect` has had its `bevy` feature removed. If you were relying
on this feature, simply enable `smallvec` and `smol_str` instead.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Alternative to and closes#18120.
Sibling to #18082, see that PR for broader reasoning.
Folks weren't sold on the name `many` (get_many is clearer, and this is
rare), and that PR is much more complex.
## Solution
- Simply deprecate `Query::many` and `Query::many_mut`
- Clean up internal usages
Mentions of this in the docs can wait until it's fully removed in the
0.17 cycle IMO: it's much easier to catch the problems when doing that.
## Testing
CI!
## Migration Guide
`Query::many` and `Query::many_mut` have been deprecated to reduce
panics and API duplication. Use `Query::get_many` and
`Query::get_many_mut` instead, and handle the `Result`.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
# Objective
simplify some code and improve Event macro
Closes https://github.com/bevyengine/bevy/issues/14336,
# Showcase
you can now write derive Events like so
```rust
#[derive(event)]
#[event(auto_propagate, traversal = MyType)]
struct MyEvent;
```
## Objective
Fixes#18092
Bevy's current error type is a simple type alias for `Box<dyn Error +
Send + Sync + 'static>`. This largely works as a catch-all error, but it
is missing a critical feature: the ability to capture a backtrace at the
point that the error occurs. The best way to do this is `anyhow`-style
error handling: a new error type that takes advantage of the fact that
the `?` `From` conversion happens "inline" to capture the backtrace at
the point of the error.
## Solution
This PR adds a new `BevyError` type (replacing our old
`std::error::Error` type alias), which uses the "from conversion
backtrace capture" approach:
```rust
fn oh_no() -> Result<(), BevyError> {
// this fails with Rust's built in ParseIntError, which
// is converted into the catch-all BevyError type
let number: usize = "hi".parse()?;
println!("parsed {number}");
Ok(())
}
```
This also updates our exported `Result` type alias to default to
`BevyError`, meaning you can write this instead:
```rust
fn oh_no() -> Result {
let number: usize = "hi".parse()?;
println!("parsed {number}");
Ok(())
}
```
When a BevyError is encountered in a system, it will use Bevy's default
system error handler (which panics by default). BevyError does custom
"backtrace filtering" by default, meaning we can cut out the _massive_
amount of "rust internals", "async executor internals", and "bevy system
scheduler internals" that show up in backtraces. It also trims out the
first generally-unnecssary `From` conversion backtrace lines that make
it harder to locate the real error location. The result is a blissfully
simple backtrace by default:
The full backtrace can be shown by setting the `BEVY_BACKTRACE=full`
environment variable. Non-BevyError panics still use the default Rust
backtrace behavior.
One issue that prevented the truly noise-free backtrace during panics
that you see above is that Rust's default panic handler will print the
unfiltered (and largely unhelpful real-panic-point) backtrace by
default, in _addition_ to our filtered BevyError backtrace (with the
helpful backtrace origin) that we capture and print. To resolve this, I
have extended Bevy's existing PanicHandlerPlugin to wrap the default
panic handler. If we panic from the result of a BevyError, we will skip
the default "print full backtrace" panic handler. This behavior can be
enabled and disabled using the new `error_panic_hook` cargo feature in
`bevy_app` (which is enabled by default).
One downside to _not_ using `Box<dyn Error>` directly is that we can no
longer take advantage of the built-in `Into` impl for strings to errors.
To resolve this, I have added the following:
```rust
// Before
Err("some error")?
// After
Err(BevyError::message("some error"))?
```
We can discuss adding shorthand methods or macros for this (similar to
anyhow's `anyhow!("some error")` macro), but I'd prefer to discuss that
later.
I have also added the following extension method:
```rust
// Before
some_option.ok_or("some error")?;
// After
some_option.ok_or_message("some error")?;
```
I've also moved all of our existing error infrastructure from
`bevy_ecs::result` to `bevy_ecs::error`, as I think that is the better
home for it
## Why not anyhow (or eyre)?
The biggest reason is that `anyhow` needs to be a "generically useful
error type", whereas Bevy is a much narrower scope. By using our own
error, we can be significantly more opinionated. For example, anyhow
doesn't do the extensive (and invasive) backtrace filtering that
BevyError does because it can't operate on Bevy-specific context, and
needs to be generically useful.
Bevy also has a lot of operational context (ex: system info) that could
be useful to attach to errors. If we have control over the error type,
we can add whatever context we want to in a structured way. This could
be increasingly useful as we add more visual / interactive error
handling tools and editor integrations.
Additionally, the core approach used is simple and requires almost no
code. anyhow clocks in at ~2500 lines of code, but the impl here uses
160. We are able to boil this down to exactly what we need, and by doing
so we improve our compile times and the understandability of our code.
# Objective
Based on #18054, this PR builds on #18035 to deprecate:
- `Commands::insert_or_spawn_batch`
- `Entities::alloc_at_without_replacement`
- `Entities::alloc_at`
- `World::insert_or_spawn_batch`
- `World::insert_or_spawn_batch_with_caller`
## Testing
Just deprecation, so no new tests. Note that as of writing #18035 is
still under testing and review.
## Open Questions
- [x] Should `entity::AllocAtWithoutReplacement` be deprecated? It is
internal and only used in `Entities::alloc_at_without_replacement`.
**EDIT:** Now deprecated.
## Migration Guide
The following functions have been deprecated:
- `Commands::insert_or_spawn_batch`
- `World::insert_or_spawn_batch`
- `World::insert_or_spawn_batch_with_caller`
These functions, when used incorrectly, can cause major performance
problems and are generally viewed as anti-patterns and foot guns. These
are planned to be removed altogether in 0.17.
Instead of these functions consider doing one of the following:
Option A) Instead of despawing entities and re-spawning them at a
particular id, insert the new `Disabled` component without despawning
the entity, and use `try_insert_batch` or `insert_batch` and remove
`Disabled` instead of re-spawning it.
Option B) Instead of giving special meaning to an entity id, simply use
`spawn_batch` and ensure entity references are valid when despawning.
---------
Co-authored-by: JaySpruce <jsprucebruce@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
This PR adds:
- function call hook attributes `#[component(on_add = func(42))]`
- main feature of this commit
- closure hook attributes `#[component(on_add = |w, ctx| { /* ... */
})]`
- maybe too verbose
- but was easy to add
- was suggested on discord
This allows to reuse common functionality without replicating a lot of
boilerplate. A small example is a hook which just adds different default
sprites. The sprite loading code would be the same for every component.
Unfortunately we can't use the required components feature, since we
need at least an `AssetServer` or other `Resource`s or `Component`s to
load the sprite.
```rs
fn load_sprite(path: &str) -> impl Fn(DeferredWorld, HookContext) {
|mut world, ctx| {
// ... use world to load sprite
}
}
#[derive(Component)]
#[component(on_add = load_sprite("knight.png"))]
struct Knight;
#[derive(Component)]
#[component(on_add = load_sprite("monster.png"))]
struct Monster;
```
---
The commit also reorders the logic of the derive macro a bit. It's
probably a bit less lazy now, but the functionality shouldn't be
performance critical and is executed at compile time anyways.
## Solution
- Introduce `HookKind` enum in the component proc macro module
- extend parsing to allow more cases of expressions
## Testing
I have some code laying around. I'm not sure where to put it yet though.
Also is there a way to check compilation failures? Anyways, here it is:
```rs
use bevy::prelude::*;
#[derive(Component)]
#[component(
on_add = fooing_and_baring,
on_insert = fooing_and_baring,
on_replace = fooing_and_baring,
on_despawn = fooing_and_baring,
on_remove = fooing_and_baring
)]
pub struct FooPath;
fn fooing_and_baring(
world: bevy::ecs::world::DeferredWorld,
ctx: bevy::ecs::component::HookContext,
) {
}
#[derive(Component)]
#[component(
on_add = baring_and_bazzing("foo"),
on_insert = baring_and_bazzing("foo"),
on_replace = baring_and_bazzing("foo"),
on_despawn = baring_and_bazzing("foo"),
on_remove = baring_and_bazzing("foo")
)]
pub struct FooCall;
fn baring_and_bazzing(
path: &str,
) -> impl Fn(bevy::ecs::world::DeferredWorld, bevy::ecs::component::HookContext) {
|world, ctx| {}
}
#[derive(Component)]
#[component(
on_add = |w,ctx| {},
on_insert = |w,ctx| {},
on_replace = |w,ctx| {},
on_despawn = |w,ctx| {},
on_remove = |w,ctx| {}
)]
pub struct FooClosure;
#[derive(Component, Debug)]
#[relationship(relationship_target = FooTargets)]
#[component(
on_add = baring_and_bazzing("foo"),
// on_insert = baring_and_bazzing("foo"),
// on_replace = baring_and_bazzing("foo"),
on_despawn = baring_and_bazzing("foo"),
on_remove = baring_and_bazzing("foo")
)]
pub struct FooTargetOf(Entity);
#[derive(Component, Debug)]
#[relationship_target(relationship = FooTargetOf)]
#[component(
on_add = |w,ctx| {},
on_insert = |w,ctx| {},
// on_replace = |w,ctx| {},
// on_despawn = |w,ctx| {},
on_remove = |w,ctx| {}
)]
pub struct FooTargets(Vec<Entity>);
// MSG: mismatched types expected fn pointer `for<'w> fn(bevy::bevy_ecs::world::DeferredWorld<'w>, bevy::bevy_ecs::component::HookContext)` found struct `Bar`
//
// pub struct Bar;
// #[derive(Component)]
// #[component(
// on_add = Bar,
// )]
// pub struct FooWrongPath;
// MSG: this function takes 1 argument but 2 arguements were supplied
//
// #[derive(Component)]
// #[component(
// on_add = wrong_bazzing("foo"),
// )]
// pub struct FooWrongCall;
//
// fn wrong_bazzing(path: &str) -> impl Fn(bevy::ecs::world::DeferredWorld) {
// |world| {}
// }
// MSG: expected 1 argument, found 2
//
// #[derive(Component)]
// #[component(
// on_add = |w| {},
// )]
// pub struct FooWrongCall;
```
---
## Showcase
I'll try to continue to work on this to have a small section in the
release notes.
# Objective
Component `require()` IDE integration is fully broken, as of #16575.
## Solution
This reverts us back to the previous "put the docs on Component trait"
impl. This _does_ reduce the accessibility of the required components in
rust docs, but the complete erasure of "required component IDE
experience" is not worth the price of slightly increased prominence of
requires in docs.
Additionally, Rust Analyzer has recently started including derive
attributes in suggestions, so we aren't losing that benefit of the
proc_macro attribute impl.
Fixes#17720
## Objective
Spawning RelationshipTargets from scenes currently fails to preserve
RelationshipTarget ordering (ex: `Children` has an arbitrary order).
This is because it uses the normal hook flow to set up the collection,
which means we are pushing onto the collection in _spawn order_ (which
is currently in archetype order, which will often produce mismatched
orderings).
We need to preserve the ordering in the original RelationshipTarget
collection. Ideally without expensive checking / fixups.
## Solution
One solution would be to spawn in hierarchy-order. However this gets
complicated as there can be multiple hierarchies, and it also means we
can't spawn in more cache-friendly orders (ex: the current per-archetype
spawning, or future even-smarter per-table spawning). Additionally,
same-world cloning has _slightly_ more nuanced needs (ex: recursively
clone linked relationships, while maintaining _original_ relationships
outside of the tree via normal hooks).
The preferred approach is to directly spawn the remapped
RelationshipTarget collection, as this trivially preserves the ordering.
Unfortunately we can't _just_ do that, as when we spawn the children
with their Relationships (ex: `ChildOf`), that will insert a duplicate.
We could "fixup" the collection retroactively by just removing the back
half of duplicates, but this requires another pass / more lookups /
allocating twice as much space. Additionally, it becomes complicated
because observers could insert additional children, making it harder
(aka more expensive) to determine which children are dupes and which are
not.
The path I chose is to support "opting out" of the relationship target
hook in the contexts that need that, as this allows us to just cheaply
clone the mapped collection. The relationship hook can look for this
configuration when it runs and skip its logic when that happens. A
"simple" / small-amount-of-code way to do this would be to add a "skip
relationship spawn" flag to World. Sadly, any hook / observer that runs
_as the result of an insert_ would also read this flag. We really need a
way to scope this setting to a _specific_ insert.
Therefore I opted to add a new `RelationshipInsertHookMode` enum and an
`entity.insert_with_relationship_insert_hook_mode` variant. Obviously
this is verbose and ugly. And nobody wants _more_ insert variants. But
sadly this was the best I could come up with from a performance and
capability perspective. If you have alternatives let me know!
There are three variants:
1. `RelationshipInsertHookMode::Run`: always run relationship insert
hooks (this is the default)
2. `RelationshipInsertHookMode::Skip`: do not run any relationship
insert hooks for this insert (this is used by spawner code)
3. `RelationshipInsertHookMode::RunIfNotLinked`: only run hooks for
_unlinked_ relationships (this is used in same-world recursive entity
cloning to preserve relationships outside of the deep-cloned tree)
Note that I have intentionally only added "insert with relationship hook
mode" variants to the cases we absolutely need (everything else uses the
default `Run` mode), just to keep the code size in check. I do not think
we should add more without real _very necessary_ use cases.
I also made some other minor tweaks:
1. I split out `SourceComponent` from `ComponentCloneCtx`. Reading the
source component no longer needlessly blocks mutable access to
`ComponentCloneCtx`.
2. Thanks to (1), I've removed the `RefCell` wrapper over the cloned
component queue.
3. (1) also allowed me to write to the EntityMapper while queuing up
clones, meaning we can reserve entities during the component clone and
write them to the mapper _before_ inserting the component, meaning
cloned collections can be mapped on insert.
4. I've removed the closure from `write_target_component_ptr` to
simplify the API / make it compatible with the split `SourceComponent`
approach.
5. I've renamed `EntityCloner::recursive` to
`EntityCloner::linked_cloning` to connect that feature more directly
with `RelationshipTarget::LINKED_SPAWN`
6. I've removed `EntityCloneBehavior::RelationshipTarget`. This was
always intended to be temporary, and this new behavior removes the need
for it.
---------
Co-authored-by: Viktor Gustavsson <villor94@gmail.com>
# Objective
Fix unsound query transmutes on queries obtained from
`Query::as_readonly()`.
The following compiles, and the call to `transmute_lens()` should panic,
but does not:
```rust
fn bad_system(query: Query<&mut A>) {
let mut readonly = query.as_readonly();
let mut lens: QueryLens<&mut A> = readonly.transmute_lens();
let other_readonly: Query<&A> = query.as_readonly();
// `lens` and `other_readonly` alias, and are both alive here!
}
```
To make `Query::as_readonly()` zero-cost, we pointer-cast
`&QueryState<D, F>` to `&QueryState<D::ReadOnly, F>`. This means that
the `component_access` for a read-only query's state may include
accesses for the original mutable version, but the `Query` does not have
exclusive access to those components! `transmute` and `join` use that
access to ensure that a join is valid, and will incorrectly allow a
transmute that includes mutable access.
As a bonus, allow `Query::join`s that output `FilteredEntityRef` or
`FilteredEntityMut` to receive access from the `other` query. Currently
they only receive access from `self`.
## Solution
When transmuting or joining from a read-only query, remove any writes
before performing checking that the transmute is valid. For joins, be
sure to handle the case where one input query was the result of
`as_readonly()` but the other has valid mutable access.
This requires identifying read-only queries, so add a
`QueryData::IS_READ_ONLY` associated constant. Note that we only call
`QueryState::as_transmuted_state()` with `NewD: ReadOnlyQueryData`, so
checking for read-only queries is sufficient to check for
`as_transmuted_state()`.
Removing writes requires allocating a new `FilteredAccess`, so only do
so if the query is read-only and the state has writes. Otherwise, the
existing access is correct and we can continue using a reference to it.
Use the new read-only state to call `NewD::set_access`, so that
transmuting to a `FilteredAccessMut` results in a read-only
`FilteredAccessMut`. Otherwise, it would take the original write access,
and then the transmute would panic because it had too much access.
Note that `join` was previously passing `self.component_access` to
`NewD::set_access`. Switching it to `joined_component_access` also
allows a join that outputs `FilteredEntity(Ref|Mut)` to receive access
from `other`. The fact that it didn't do that before seems like an
oversight, so I didn't try to prevent that change.
## Testing
Added unit tests with the unsound transmute and join.
# Objective
Many systems like `Schedule` rely on the fact that every structural ECS
changes are deferred until an exclusive system flushes the `World`
itself. This gives us the benefits of being able to run systems in
parallel without worrying about dangling references caused by memory
(re)allocations, which will in turn lead to **Undefined Behavior**.
However, this isn't explicitly documented in `SystemParam`; currently it
only vaguely hints that in `init_state`, based on the fact that
structural ECS changes require mutable access to the _whole_ `World`.
## Solution
Document this behavior explicitly in `SystemParam`'s type-level
documentations.
# Objective
- Fixes#16339
## Solution
- Replaced `component_reads_and_writes` and `component_writes` with
`try_iter_component_access`.
## Testing
- Ran `dynamic` example to confirm behaviour is unchanged.
- CI
---
## Migration Guide
The following methods (some removed in previous PRs) are now replaced by
`Access::try_iter_component_access`:
* `Access::component_reads_and_writes`
* `Access::component_reads`
* `Access::component_writes`
As `try_iter_component_access` returns a `Result`, you'll now need to
handle the failing case (e.g., `unwrap()`). There is currently a single
failure mode, `UnboundedAccess`, which occurs when the `Access` is for
all `Components` _except_ certain exclusions. Since this list is
infinite, there is no meaningful way for `Access` to provide an
iterator. Instead, get a list of components (e.g., from the `Components`
structure) and iterate over that instead, filtering using
`Access::has_component_read`, `Access::has_component_write`, etc.
Additionally, you'll need to `filter_map` the accesses based on which
method you're attempting to replace:
* `Access::component_reads_and_writes` -> `Exclusive(_) | Shared(_)`
* `Access::component_reads` -> `Shared(_)`
* `Access::component_writes` -> `Exclusive(_)`
To ease migration, please consider the below extension trait which you
can include in your project:
```rust
pub trait AccessCompatibilityExt {
/// Returns the indices of the components this has access to.
fn component_reads_and_writes(&self) -> impl Iterator<Item = T> + '_;
/// Returns the indices of the components this has non-exclusive access to.
fn component_reads(&self) -> impl Iterator<Item = T> + '_;
/// Returns the indices of the components this has exclusive access to.
fn component_writes(&self) -> impl Iterator<Item = T> + '_;
}
impl<T: SparseSetIndex> AccessCompatibilityExt for Access<T> {
fn component_reads_and_writes(&self) -> impl Iterator<Item = T> + '_ {
self
.try_iter_component_access()
.expect("Access is unbounded. Please refactor the usage of this method to directly use try_iter_component_access")
.filter_map(|component_access| {
let index = component_access.index().sparse_set_index();
match component_access {
ComponentAccessKind::Archetypal(_) => None,
ComponentAccessKind::Shared(_) => Some(index),
ComponentAccessKind::Exclusive(_) => Some(index),
}
})
}
fn component_reads(&self) -> impl Iterator<Item = T> + '_ {
self
.try_iter_component_access()
.expect("Access is unbounded. Please refactor the usage of this method to directly use try_iter_component_access")
.filter_map(|component_access| {
let index = component_access.index().sparse_set_index();
match component_access {
ComponentAccessKind::Archetypal(_) => None,
ComponentAccessKind::Shared(_) => Some(index),
ComponentAccessKind::Exclusive(_) => None,
}
})
}
fn component_writes(&self) -> impl Iterator<Item = T> + '_ {
self
.try_iter_component_access()
.expect("Access is unbounded. Please refactor the usage of this method to directly use try_iter_component_access")
.filter_map(|component_access| {
let index = component_access.index().sparse_set_index();
match component_access {
ComponentAccessKind::Archetypal(_) => None,
ComponentAccessKind::Shared(_) => None,
ComponentAccessKind::Exclusive(_) => Some(index),
}
})
}
}
```
Please take note of the use of `expect(...)` in these methods. You
should consider using these as a starting point for a more appropriate
migration based on your specific needs.
## Notes
- This new method is fallible based on whether the `Access` is bounded
or unbounded (unbounded occurring with inverted component sets). If
bounded, will return an iterator of every item and its access level. I
believe this makes sense without exposing implementation details around
`Access`.
- The access level is defined by an `enum` `ComponentAccessKind<T>`,
either `Archetypical`, `Shared`, or `Exclusive`. As a convenience, this
`enum` has a method `index` to get the inner `T` value without a match
statement. It does add more code, but the API is clearer.
- Within `QueryBuilder` this new method simplifies several pieces of
logic without changing behaviour.
- Within `QueryState` the logic is simplified and the amount of
iteration is reduced, potentially improving performance.
- Within the `dynamic` example it has identical behaviour, with the
inversion footgun explicitly highlighted by an `unwrap`.
---------
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Co-authored-by: Mike <2180432+hymm@users.noreply.github.com>
# Objective
Minimal implementation of directed one-to-one relationships via
implementing `RelationshipSourceCollection` for `Entity`.
Now you can do
```rust
#[derive(Component)]
#[relationship(relationship_target = Below)]
pub struct Above(Entity);
#[derive(Component)]
#[relationship_target(relationship = Above)]
pub struct Below(Entity);
```
## Future Work
It would be nice if the relationships could be fully symmetrical in the
future - in the example above, since `Above` is the source of truth you
can't add `Below` to an entity and have `Above` added automatically.
## Testing
Wrote unit tests for new relationship sources and and verified
adding/removing relationships maintains connection as expected.
# Objective
- Fixes the issue described in this comment:
https://github.com/bevyengine/bevy/issues/16680#issuecomment-2522764239.
## Solution
- Cache one-shot systems by `S: IntoSystem` (which is const-asserted to
be a ZST) rather than `S::System`.
## Testing
Added a new unit test named `cached_system_into_same_system_type` to
`system_registry.rs`.
---
## Migration Guide
The `CachedSystemId` resource has been changed:
```rust
// Before:
let cached_id = CachedSystemId::<S::System>(id);
assert!(id == cached_id.0);
// After:
let cached_id = CachedSystemId::<S>::new(id);
assert!(id == SystemId::from_entity(cached_id.entity));
```
The test case `query_iter_sorts` was doing lots of comparisons to ensure
that various query arrays were sorted, but the arrays were all empty.
This PR spawns some entities so that the entity lists to compare not
empty, and sorting can actually be tested for correctness.
# Objective
As discussed in #14275, Bevy is currently too prone to panic, and makes
the easy / beginner-friendly way to do a large number of operations just
to panic on failure.
This is seriously frustrating in library code, but also slows down
development, as many of the `Query::single` panics can actually safely
be an early return (these panics are often due to a small ordering issue
or a change in game state.
More critically, in most "finished" products, panics are unacceptable:
any unexpected failures should be handled elsewhere. That's where the
new
With the advent of good system error handling, we can now remove this.
Note: I was instrumental in a) introducing this idea in the first place
and b) pushing to make the panicking variant the default. The
introduction of both `let else` statements in Rust and the fancy system
error handling work in 0.16 have changed my mind on the right balance
here.
## Solution
1. Make `Query::single` and `Query::single_mut` (and other random
related methods) return a `Result`.
2. Handle all of Bevy's internal usage of these APIs.
3. Deprecate `Query::get_single` and friends, since we've moved their
functionality to the nice names.
4. Add detailed advice on how to best handle these errors.
Generally I like the diff here, although `get_single().unwrap()` in
tests is a bit of a downgrade.
## Testing
I've done a global search for `.single` to track down any missed
deprecated usages.
As to whether or not all the migrations were successful, that's what CI
is for :)
## Future work
~~Rename `Query::get_single` and friends to `Query::single`!~~
~~I've opted not to do this in this PR, and smear it across two releases
in order to ease the migration. Successive deprecations are much easier
to manage than the semantics and types shifting under your feet.~~
Cart has convinced me to change my mind on this; see
https://github.com/bevyengine/bevy/pull/18082#discussion_r1974536085.
## Migration guide
`Query::single`, `Query::single_mut` and their `QueryState` equivalents
now return a `Result`. Generally, you'll want to:
1. Use Bevy 0.16's system error handling to return a `Result` using the
`?` operator.
2. Use a `let else Ok(data)` block to early return if it's an expected
failure.
3. Use `unwrap()` or `Ok` destructuring inside of tests.
The old `Query::get_single` (etc) methods which did this have been
deprecated.
I noticed this while working on #18017 . Some of the `stderr`
compile_fail tests were updated while I generated the output for the new
tests I introduced in the mentioned PR.
I'm on rust 1.85.0
## Objective
`EntityCommands::trigger` internally uses `Commands::trigger_targets`,
which means it gets queued using `Commands::queue` rather
`EntityCommands::queue`. This previously wouldn't have made much
difference, but now entity commands check whether the entity exists, and
that check never happens in this case.
## Solution
- Add `entity_command::trigger`, which calls the same function as before
(`World::trigger_targets_with_caller`) but through the `EntityWorldMut`
passed to entity commands.
- Change `EntityCommands::trigger` to queue the new entity command
normally.
https://github.com/bevyengine/bevy/pull/17905 replaced `ChildOf(entity)`
with `ChildOf { parent: entity }`, but some deprecation advice was
overlooked. Also corrected formatting in documentation.
## Testing
Added a `set_parent` to a random example. Confirmed that the deprecation
warning shows and the advice can be pasted in.
# Objective
There are currently three ways to access the parent stored on a ChildOf
relationship:
1. `child_of.parent` (field accessor)
2. `child_of.get()` (get function)
3. `**child_of` (Deref impl)
I will assert that we should only have one (the field accessor), and
that the existence of the other implementations causes confusion and
legibility issues. The deref approach is heinous, and `child_of.get()`
is significantly less clear than `child_of.parent`.
## Solution
Remove `impl Deref for ChildOf` and `ChildOf::get`.
The one "downside" I'm seeing is that:
```rust
entity.get::<ChildOf>().map(ChildOf::get)
```
Becomes this:
```rust
entity.get::<ChildOf>().map(|c| c.parent)
```
I strongly believe that this is worth the increased clarity and
consistency. I'm also not really a huge fan of the "pass function
pointer to map" syntax. I think most people don't think this way about
maps. They think in terms of a function that takes the item in the
Option and returns the result of some action on it.
## Migration Guide
```rust
// Before
**child_of
// After
child_of.parent
// Before
child_of.get()
// After
child_of.parent
// Before
entity.get::<ChildOf>().map(ChildOf::get)
// After
entity.get::<ChildOf>().map(|c| c.parent)
```
## Objective
Alternative to #18001.
- Now that systems can handle the `?` operator, `get_entity` returning
`Result` would be more useful than `Option`.
- With `get_entity` being more flexible, combined with entity commands
now checking the entity's existence automatically, the panic in `entity`
isn't really necessary.
## Solution
- Changed `Commands::get_entity` to return `Result<EntityCommands,
EntityDoesNotExistError>`.
- Removed panic from `Commands::entity`.
# Objective
fixes#17896
## Solution
Change ChildOf ( Entity ) to ChildOf { parent: Entity }
by doing this we also allow users to use named structs for relationship
derives, When you have more than 1 field in a struct with named fields
the macro will look for a field with the attribute #[relationship] and
all of the other fields should implement the Default trait. Unnamed
fields are still supported.
When u have a unnamed struct with more than one field the macro will
fail.
Do we want to support something like this ?
```rust
#[derive(Component)]
#[relationship_target(relationship = ChildOf)]
pub struct Children (#[relationship] Entity, u8);
```
I could add this, it but doesn't seem nice.
## Testing
crates/bevy_ecs - cargo test
## Showcase
```rust
use bevy_ecs::component::Component;
use bevy_ecs::entity::Entity;
#[derive(Component)]
#[relationship(relationship_target = Children)]
pub struct ChildOf {
#[relationship]
pub parent: Entity,
internal: u8,
};
#[derive(Component)]
#[relationship_target(relationship = ChildOf)]
pub struct Children {
children: Vec<Entity>
};
```
---------
Co-authored-by: Tim Overbeek <oorbecktim@Tims-MacBook-Pro.local>
Co-authored-by: Tim Overbeek <oorbecktim@c-001-001-042.client.nl.eduvpn.org>
Co-authored-by: Tim Overbeek <oorbecktim@c-001-001-059.client.nl.eduvpn.org>
Co-authored-by: Tim Overbeek <oorbecktim@c-001-001-054.client.nl.eduvpn.org>
Co-authored-by: Tim Overbeek <oorbecktim@c-001-001-027.client.nl.eduvpn.org>
## Objective
`insert_by_id` is unsafe, but I forgot to add that to the
manually-queueable version in `entity_command`.
It also can only insert using `InsertMode::Replace`, when it could
easily be configurable by threading an `InsertMode` parameter to the
final `BundleInserter::insert` call.
## Solution
- Add `unsafe` and safety comment.
- Add `InsertMode` parameter to `entity_command::insert_by_id`,
`EntityWorldMut::insert_by_id_with_caller`, and
`EntityWorldMut::insert_dynamic_bundle`.
- Add `InsertMode` parameter to `entity_command::insert` and remove
`entity_command::insert_if_new`, for consistency with the other
manually-queued insertion commands.
# Objective
Fixes#17828
This fixes two bugs:
1. Exclusive systems should see the effect of all commands queued to
that point. That does not happen when the system is configured with
`*_ignore_deferred` which may lead to surprising situations. These
configurations should not behave like that.
2. If `*_ignore_deferred` is used, no sync point may be added at all
**after** the config. Currently this can happen if the last nodes in
that config have no deferred parameters themselves. Instead, sync points
should always be added after such a config, so long systems have
deferred parameters.
## Solution
1. When adding sync points on edges, do not consider
`AutoInsertApplyDeferredPass::no_sync_edges` if the target is an
exclusive system.
2. when going through the nodes in a directed way, store the information
that `AutoInsertApplyDeferredPass::no_sync_edges` suppressed adding a
sync point at the target node. Then, when the target node is evaluated
later by the iteration and that prior suppression was the case, the
target node will behave like it has deferred parameters even if the
system itself does not.
## Testing
I added a test for each bug, please let me know if more are wanted and
if yes, which cases you would want to see.
These tests also can be read as examples how the current code would
fail.
# Objective
`QueryIter::sort_by()` is unsound. It passes the lens items with the
full `'w` lifetime, and a malicious user could smuggle them out of the
closure where they could alias with the query results.
## Solution
Make the sort closures generic in the lifetime parameter of the lens
item. This ensures the lens items cannot outlive the call to the
closure.
## Testing
Added a compile-fail test that demonstrates the unsound pattern.
## Migration Guide
The `sort` family of methods on `QueryIter` unsoundly gave access
`L::Item<'w>` with the full `'w` lifetime. It has been shortened to
`L::Item<'w>` so that items cannot escape the comparer. If you get
lifetime errors using these methods, you will need to make the comparer
generic in the new lifetime. Often this can be done by replacing named
`'w` with `'_`, or by replacing the use of a function item with a
closure.
```rust
// Before: Now fails with "error: implementation of `FnMut` is not general enough"
query.iter().sort_by::<&C>(Ord::cmp);
// After: Wrap in a closure
query.iter().sort_by::<&C>(|l, r| Ord::cmp(l, r));
query.iter().sort_by::<&C>(comparer);
// Before: Uses specific `'w` lifetime from some outer scope
// now fails with "error: implementation of `FnMut` is not general enough"
fn comparer(left: &&'w C, right: &&'w C) -> Ordering { /* ... */ }
// After: Accepts any lifetime using inferred lifetime parameter
fn comparer(left: &&C, right: &&C) -> Ordering { /* ... */ }
# Objective
- Fixes#16416
## Solution
- Add a intermediate temporary mutable `RequiredComponents` to get avoid
of the borrowing issues.
## Testing
- I have run `cargo test --package bevy_ecs -- --exact --show-output`
and past all the tests.
