# Objective
- Reverts unnecessary version increase for `thiserror` caused by the following PR. 9066d51420
- The aforementioned PR should have increased `thiserrror` version uniformly across all bevy crates. As far as I can tell it was unneccessary to bump versions
## Solution
- Revert versions to the matching version used by other bevy "crates"
```
MBP-Larry-Du.local:~/Code/bevy:$ git grep thiserror
CHANGELOG.md:- [Derive thiserror::Error for HexColorError][2740]
crates/bevy_asset/Cargo.toml:thiserror = "1.0"
crates/bevy_asset/src/asset_server.rs:use thiserror::Error;
crates/bevy_asset/src/io/mod.rs:use thiserror::Error;
crates/bevy_gltf/Cargo.toml:thiserror = "1.0"
crates/bevy_gltf/src/loader.rs:use thiserror::Error;
crates/bevy_input/Cargo.toml:thiserror = "1.0"
crates/bevy_input/src/gamepad.rs:use thiserror::Error;
crates/bevy_reflect/Cargo.toml:thiserror = "1.0"
crates/bevy_reflect/src/path.rs:use thiserror::Error;
crates/bevy_render/Cargo.toml:thiserror = "1.0"
```
---
## Changelog
> This section is optional. If this was a trivial fix, or has no externally-visible impact, you can delete this section.
- What changed as a result of this PR? Fixed dependency conflict for building projects.
Current build of StarRust runs successfully with the `thiserror` reversion: https://github.com/LarsDu/StarRust
But will run into dependency conflicts if `thiserror` is version 1.037
Co-authored-by: Larry Du <larry.du@freenome.com>
# Objective
I was trying to implement a collision system for my game, and believed that the iter_combinations method might be what I need. But I couldn't find a simple explanation of what a combination was in Bevy and thought it could use some more explanation.
## Solution
I added some description to the documentation that can hopefully further elaborate on what a combination is.
I also changed up the docs for the method because a combination is a different thing than a permutation but the Bevy docs seemed to use them interchangeably.
# Objective
- `QueryCombinationIter` can have sizes greater than `usize::MAX`.
- Fixes#5846
## Solution
- Only the implementation of `ExactSizeIterator` has been removed. Instead of using `query_combination.len()`, you can use `query_combination.size_hint().0` to get the same value as before.
---
## Migration Guide
- Switch to using other methods of getting the length.
# Objective
Fixes#5884#2879
Alternative to #2988#5885#2886
"Immutable" Plugin settings are currently represented as normal ECS resources, which are read as part of plugin init. This presents a number of problems:
1. If a user inserts the plugin settings resource after the plugin is initialized, it will be silently ignored (and use the defaults instead)
2. Users can modify the plugin settings resource after the plugin has been initialized. This creates a false sense of control over settings that can no longer be changed.
(1) and (2) are especially problematic and confusing for the `WindowDescriptor` resource, but this is a general problem.
## Solution
Immutable Plugin settings now live on each Plugin struct (ex: `WindowPlugin`). PluginGroups have been reworked to support overriding plugin values. This also removes the need for the `add_plugins_with` api, as the `add_plugins` api can use the builder pattern directly. Settings that can be used at runtime continue to be represented as ECS resources.
Plugins are now configured like this:
```rust
app.add_plugin(AssetPlugin {
watch_for_changes: true,
..default()
})
```
PluginGroups are now configured like this:
```rust
app.add_plugins(DefaultPlugins
.set(AssetPlugin {
watch_for_changes: true,
..default()
})
)
```
This is an alternative to #2988, which is similar. But I personally prefer this solution for a couple of reasons:
* ~~#2988 doesn't solve (1)~~ #2988 does solve (1) and will panic in that case. I was wrong!
* This PR directly ties plugin settings to Plugin types in a 1:1 relationship, rather than a loose "setup resource" <-> plugin coupling (where the setup resource is consumed by the first plugin that uses it).
* I'm not a huge fan of overloading the ECS resource concept and implementation for something that has very different use cases and constraints.
## Changelog
- PluginGroups can now be configured directly using the builder pattern. Individual plugin values can be overridden by using `plugin_group.set(SomePlugin {})`, which enables overriding default plugin values.
- `WindowDescriptor` plugin settings have been moved to `WindowPlugin` and `AssetServerSettings` have been moved to `AssetPlugin`
- `app.add_plugins_with` has been replaced by using `add_plugins` with the builder pattern.
## Migration Guide
The `WindowDescriptor` settings have been moved from a resource to `WindowPlugin::window`:
```rust
// Old (Bevy 0.8)
app
.insert_resource(WindowDescriptor {
width: 400.0,
..default()
})
.add_plugins(DefaultPlugins)
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(WindowPlugin {
window: WindowDescriptor {
width: 400.0,
..default()
},
..default()
}))
```
The `AssetServerSettings` resource has been removed in favor of direct `AssetPlugin` configuration:
```rust
// Old (Bevy 0.8)
app
.insert_resource(AssetServerSettings {
watch_for_changes: true,
..default()
})
.add_plugins(DefaultPlugins)
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(AssetPlugin {
watch_for_changes: true,
..default()
}))
```
`add_plugins_with` has been replaced by `add_plugins` in combination with the builder pattern:
```rust
// Old (Bevy 0.8)
app.add_plugins_with(DefaultPlugins, |group| group.disable::<AssetPlugin>());
// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.build().disable::<AssetPlugin>());
```
# Objective
Scenes are currently represented as a list of entities. This is all we need currently, but we may want to add more data to this format in the future (metadata, asset lists, etc.).
It would be nice to update the format in preparation of possible future changes. Doing so now (i.e., before 0.9) could mean reduced[^1] breakage for things added in 0.10.
[^1]: Obviously, adding features runs the risk of breaking things regardless. But if all features added are for whatever reason optional or well-contained, then users should at least have an easier time updating.
## Solution
Made the scene root a struct rather than a list.
```rust
(
entities: [
// Entity data here...
]
)
```
---
## Changelog
* The scene format now puts the entity list in a newly added `entities` field, rather than having it be the root object
## Migration Guide
The scene file format now uses a struct as the root object rather than a list of entities. The list of entities is now found in the `entities` field of this struct.
```rust
// OLD
[
(
entity: 0,
components: [
// Components...
]
),
]
// NEW
(
entities: [
(
entity: 0,
components: [
// Components...
]
),
]
)
```
Co-authored-by: Gino Valente <49806985+MrGVSV@users.noreply.github.com>
# Objective
- You usually want to say that a given animation *should* be playing, doing nothing if it's already playing.
## Solution
- Rename play to start and add new play method that won't overwrite the existing animation if it's already playing #6350
---
## Changelog
### Changed
`AnimationPlayer::play` will now not restart the animation if it's already playing
### Added
An `AnimationPlayer ::start` method, which has the old behavior of `play`
## Migration guide
- If you were using `play` to restart an animation that was already playing, that functionality has been moved to `start`. Now, `play` won't have any effect if the requested animation is already playing.
# Objective
Improve ergonomics by passing on the `IntoIterator` impl of the underlying type to wrapper types.
## Solution
Implement `IntoIterator` for ECS wrapper types (Mut, Local, Res, etc.).
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Improve #3953
## Solution
- The very specific circumstances under which the render world is reset meant that the flush_as_invalid function could be replaced with one that had a noop as its init method.
- This removes a double-writing issue leading to greatly increased performance.
Running the reproduction code in the linked issue, this change nearly doubles the framerate.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Avoids creating a `SurfaceConfiguration` for every window in every frame for the `prepare_windows` system
- As such also avoid calling `get_supported_formats` for every window in every frame
## Solution
- Construct `SurfaceConfiguration` lazyly in `prepare_windows`
---
This also changes the error message for failed initial surface configuration from "Failed to acquire next swapchain texture" to "Error configuring surface".
# Objective
When running the scene example, you might notice we end up printing out the following:
```ron
// ...
{
"scene::ComponentB": (
value: "hello",
_time_since_startup: (
secs: 0,
nanos: 0,
),
),
},
// ...
```
We should not be printing out `_time_since_startup` as the field is marked with `#[reflect(skip_serializing)]`:
```rust
#[derive(Component, Reflect)]
#[reflect(Component)]
struct ComponentB {
pub value: String,
#[reflect(skip_serializing)]
pub _time_since_startup: Duration,
}
```
This is because when we create the `DynamicScene`, we end up calling `Reflect::clone_value`:
82126697ee/crates/bevy_scene/src/dynamic_scene_builder.rs (L114-L114)
This results in non-Value types being cloned into Dynamic types, which means the `TypeId` returned from `reflected_value.type_id()` is not the same as the original component's.
And this meant we were not able to locate the correct `TypeRegistration`.
## Solution
Use `TypeInfo::type_id()` instead of calling `Any::type_id()` on the value directly.
---
## Changelog
* Fix a bug introduced in `0.9.0-dev` where scenes disregarded component's type registrations
# Objective
- Clipping (visible in the UI example with text scrolling) is funky
- Fixes#6287
## Solution
- Fix UV calculation:
- correct order for values (issue introduced in #6000)
- add the `y` values instead of subtracting them now that vertical order is reversed
- take scale factor into account (bug already present before reversing the order)
- While around clipping, I changed clip to only mutate when changed
No more funkiness! 😞
<img width="696" alt="Screenshot 2022-10-23 at 22 44 18" src="https://user-images.githubusercontent.com/8672791/197417721-30ad4150-5264-427f-ac82-e5265c1fb3a9.png">
# Objective
Fixes#6339.
## Solution
This PR adds a new type, `GamepadInfo`, which holds metadata associated with a particular `Gamepad`. The `Gamepads` resource now holds a `HashMap<Gamepad, GamepadInfo>`. The `GamepadInfo` is created when the gamepad backend (by default `bevy_gilrs`) emits a "gamepad connected" event.
The `gamepad_viewer` example has been updated to showcase the new functionality.
Before:
After:
---
## Changelog
### Added
- Added `GamepadInfo`.
- Added `Gamepads::name()`, which returns the name of the specified gamepad if it exists.
### Changed
- `GamepadEventType::Connected` is now a tuple variant with a single field of type `GamepadInfo`.
- Since `GamepadInfo` is not `Copy`, `GamepadEventType` is no longer `Copy`. The same is true of `GamepadEvent` and `GamepadEventRaw`.
## Migration Guide
- Pattern matches on `GamepadEventType::Connected` will need to be updated, as the form of the variant has changed.
- Code that requires `GamepadEvent`, `GamepadEventRaw` or `GamepadEventType` to be `Copy` will need to be updated.
I found myself doing
```rust
let child = commands.spawn(..).id();
commands.entity(parent).add_child(child);
```
When that could just be
```rust
commands.spawn(..).set_parent(parent);
```
Adding `set_parent` was trivial as it's just an `AddChild` command. Most of the changes are for `remove_parent`.
Also updated some outdated docs.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
Adds a better interface for performing mathematical operations with UI unit `Val`. Fixes#6080.
## Solution
- Added `try_add` and `try_sub` methods to Val.
- Removed the `Add` and `AddAssign` impls for `Val` that introduced unintuitive and bug-prone behaviour.
- As a consequence of the prior, ~~changed the `Add` and `Sub` impls for the `Size` struct to take a `(Val, Val)` instead of `Vec2`~~ deleted the `Add` and `Sub` impls for the `Size` struct
- Added a `From<(Val, Val)>` impl for the `Size` struct
- Added `evaluate(size: f32)` method that converts from `Val::Percent` to `Val::Px`.
- Added `try_add_with_size` and `try_sub_with_size` methods to `Val`, which evaluate `Val::Percent` values into `Val::Px` values before adding.
---
## Migration Guide
Instead of using the + and - operators, perform calculations on `Val`s using the new `try_add` and `try_sub` methods. Multiplication and division remained unchanged. Also, when adding or subtracting from `Size`, ~~use a `Val` tuple instead of `Vec2`~~ perform the addition on `width` and `height` separately.
Co-authored-by: Dawid Piotrowski <41804418+Pietrek14@users.noreply.github.com>
# Objective
Fixes#5559
Replaces #5628
## Solution
Because the generated method from_components() creates an instance of Self my implementation requires any field type that is marked to be ignored to implement Default.
---
## Changelog
Added the possibility to ignore fields in a bundle with `#[bundle(ignore)]`. Typically used when `PhantomData` needs to be added to a `Bundle`.
# Objective
- #4466 broke local tasks running.
- Fixes https://github.com/bevyengine/bevy/issues/6120
## Solution
- Add system for ticking local executors on main thread into bevy_core where the tasks pools are initialized.
- Add ticking local executors into thread executors
## Changelog
- tick all thread local executors in task pool.
## Notes
- ~~Not 100% sure about this PR. Ticking the local executor for the main thread in scope feels a little kludgy as it requires users of bevy_tasks to be calling scope periodically for those tasks to make progress.~~ took this out in favor of a system that ticks the local executors.
# Objective
- Fix disabling features in bevy_ecs (broken by #5630)
- Add tests in CI for bevy_ecs, bevy_reflect and bevy as those crates could be use standalone
Add the following message:
```
Items are returned in the order of the list of entities.
Entities that don't match the query are skipped.
```
Additionally, the docs in `iter.rs` and `state.rs` were updated to match those in `query.rs`.
Co-authored-by: devil-ira <justthecooldude@gmail.com>
# Objective
- Add Time-Adjusted Rolling EMA-based smoothing to diagnostics.
- Closes#4983; see that issue for more more information.
## Terms
- EMA - [Exponential Moving Average](https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average)
- SMA - [Simple Moving Average](https://en.wikipedia.org/wiki/Moving_average#Simple_moving_average)
## Solution
- We use a fairly standard approximation of a true EMA where $EMA_{\text{frame}} = EMA_{\text{previous}} + \alpha \left( x_{\text{frame}} - EMA_{\text{previous}} \right)$ where $\alpha = \Delta t / \tau$ and $\tau$ is an arbitrary smoothness factor. (See #4983 for more discussion of the math.)
- The smoothness factor is here defaulted to $2 / 21$; this was chosen fairly arbitrarily as supposedly related to the existing 20-bucket SMA.
- The smoothness factor can be set on a per-diagnostic basis via `Diagnostic::with_smoothing_factor`.
---
## Changelog
### Added
- `Diagnostic::smoothed` - provides an exponentially smoothed view of a recorded diagnostic, to e.g. reduce jitter in frametime readings.
### Changed
- `LogDiagnosticsPlugin` now records the smoothed value rather than the raw value.
- For diagnostics recorded less often than every 0.1 seconds, this change to defaults will have no visible effect.
- For discrete diagnostics where this smoothing is not desirable, set a smoothing factor of 0 to disable smoothing.
- The average of the recent history is still shown when available.
# Objective
At least partially addresses #6282.
Resources are currently stored as a dedicated Resource archetype (ID 1). This allows for easy code reusability, but unnecessarily adds 72 bytes (on 64-bit systems) to the struct that is only used for that one archetype. It also requires several fields to be `pub(crate)` which isn't ideal.
This should also remove one sparse-set lookup from fetching, inserting, and removing resources from a `World`.
## Solution
- Add `Resources` parallel to `Tables` and `SparseSets` and extract the functionality used by `Archetype` in it.
- Remove `unique_components` from `Archetype`
- Remove the `pub(crate)` on `Archetype::components`.
- Remove `ArchetypeId::RESOURCE`
- Remove `Archetypes::resource` and `Archetypes::resource_mut`
---
## Changelog
Added: `Resources` type to store resources.
Added: `Storages::resource`
Removed: `ArchetypeId::RESOURCE`
Removed: `Archetypes::resource` and `Archetypes::resources`
Removed: `Archetype::unique_components` and `Archetypes::unique_components_mut`
## Migration Guide
Resources have been moved to `Resources` under `Storages` in `World`. All code dependent on `Archetype::unique_components(_mut)` should access it via `world.storages().resources()` instead.
All APIs accessing the raw data of individual resources (mutable *and* read-only) have been removed as these APIs allowed for unsound unsafe code. All usages of these APIs should be changed to use `World::{get, insert, remove}_resource`.
# Objective
Speed up queries that are fragmented over many empty archetypes and tables.
## Solution
Add a early-out to check if the table or archetype is empty before iterating over it. This adds an extra branch for every archetype matched, but skips setting the archetype/table to the underlying state and any iteration over it.
This may not be worth it for the default `Query::iter` and maybe even the `Query::for_each` implementations, but this definitely avoids scheduling unnecessary tasks in the `Query::par_for_each` case.
Ideally, `matched_archetypes` should only contain archetypes where there's actually work to do, but this would add a `O(n)` flat cost to every call to `update_archetypes` that scales with the number of matched archetypes.
TODO: Benchmark
# Objective
- Make `Time` API more consistent.
- Support time accel/decel/pause.
## Solution
This is just the `Time` half of #3002. I was told that part isn't controversial.
- Give the "delta time" and "total elapsed time" methods `f32`, `f64`, and `Duration` variants with consistent naming.
- Implement accelerating / decelerating the passage of time.
- Implement stopping time.
---
## Changelog
- Changed `time_since_startup` to `elapsed` because `time.time_*` is just silly.
- Added `relative_speed` and `set_relative_speed` methods.
- Added `is_paused`, `pause`, `unpause` , and methods. (I'd prefer `resume`, but `unpause` matches `Timer` API.)
- Added `raw_*` variants of the "delta time" and "total elapsed time" methods.
- Added `first_update` method because there's a non-zero duration between startup and the first update.
## Migration Guide
- `time.time_since_startup()` -> `time.elapsed()`
- `time.seconds_since_startup()` -> `time.elapsed_seconds_f64()`
- `time.seconds_since_startup_wrapped_f32()` -> `time.elapsed_seconds_wrapped()`
If you aren't sure which to use, most systems should continue to use "scaled" time (e.g. `time.delta_seconds()`). The realtime "unscaled" time measurements (e.g. `time.raw_delta_seconds()`) are mostly for debugging and profiling.
# Objective
Use saturate wgsl function now implemented in naga (version 0.10.0). There is now no need for one in utils.wgsl.
naga's version allows usage for not only scalars but vectors as well.
## Solution
Remove the utils.wgsl saturate function.
## Changelog
Remove saturate function from utils.wgsl in favor of saturate in naga v0.10.0.
# Objective
I recently wanted to look at the possibility of adding `Mutated` and `Unchanged` query filters and was confronted with some seemingly unrelated broken tests.
These tests were written in such a way that changing the number of WorldQuery impls in the project would break them.
Fortunately, a [very recent release of trybuild](https://github.com/dtolnay/trybuild/releases/tag/1.0.70) has made this unnecessary.
## Solution
Replace hardcoded numbers in test output with `$N` placeholders.
# Objective
Fixes https://github.com/bevyengine/bevy/issues/6306
## Solution
Change the failing assert and expand example to explain when ordering is deterministic or not.
Co-authored-by: Mike Hsu <mike.hsu@gmail.com>
# Objective
The `RenderLayers` type is never registered, making it unavailable for reflection.
## Solution
Register it in `CameraPlugin`, the same plugin that registers the related `Visibility*` types.
# Objective
Alternative to #6150
Dependabot's PR doesn't seem to break anything, but there are some deprecations that we might as well fix up.
## Solution
https://github.com/clap-rs/clap/blob/master/CHANGELOG.md#migrating
Update clap in `build-wasm-example` and `span-cmp`. Other tools don't use clap.
Remove references to `value_parser`. It's the default now.
Change `#[clap()]` to `#[arg()]`.
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
# Objective
- Update `wgpu` to 0.14.0, `naga` to `0.10.0`, `winit` to 0.27.4, `raw-window-handle` to 0.5.0, `ndk` to 0.7.
## Solution
---
## Changelog
### Changed
- Changed `RawWindowHandleWrapper` to `RawHandleWrapper` which wraps both `RawWindowHandle` and `RawDisplayHandle`, which satisfies the `impl HasRawWindowHandle and HasRawDisplayHandle` that `wgpu` 0.14.0 requires.
- Changed `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, change its type from `bool` to `bevy_window::CursorGrabMode`.
## Migration Guide
- Adjust usage of `bevy_window::WindowDescriptor`'s `cursor_locked` to `cursor_grab_mode`, and adjust its type from `bool` to `bevy_window::CursorGrabMode`.
# Objective
Fix a camera ambiguity warning in the IOS example
## Solution
I'm assuming that this was accidentally added when UI cameras stopped being a thing. So just delete the extra camera.
# Objective
To be consistent like other examples, it's better to keep file name and example name same, so we don't need to find correct example name in Cargo.toml.
## Solution
Rename example file scaling.rs to ui_scaling.rs.
# Objective
Resolves#6197
Make it so that doc comments can be retrieved via reflection.
## Solution
Adds the new `documentation` feature to `bevy_reflect` (disabled by default).
When enabled, documentation can be found using `TypeInfo::doc` for reflected types:
```rust
/// Some struct.
///
/// # Example
///
/// ```ignore
/// let some_struct = SomeStruct;
/// ```
#[derive(Reflect)]
struct SomeStruct;
let info = <SomeStruct as Typed>::type_info();
assert_eq!(
Some(" Some struct.\n\n # Example\n\n ```ignore\n let some_struct = SomeStruct;\n ```"),
info.docs()
);
```
### Notes for Reviewers
The bulk of the files simply added the same 16 lines of code (with slightly different documentation). Most of the real changes occur in the `bevy_reflect_derive` files as well as in the added tests.
---
## Changelog
* Added `documentation` feature to `bevy_reflect`
* Added `TypeInfo::docs` method (and similar methods for all info types)
# Objective
Fixes#6272
## Solution
Revert to old way of positioning text for Text2D rendered text.
Co-authored-by: Michel van der Hulst <hulstmichel@gmail.com>
# Objective
Make toggling the visibility of an entity slightly more convenient.
## Solution
Add a mutating `toggle` method to the `Visibility` component
```rust
fn my_system(mut query: Query<&mut Visibility, With<SomeMarker>>) {
let mut visibility = query.single_mut();
// before:
visibility.is_visible = !visibility.is_visible;
// after:
visibility.toggle();
}
```
## Changelog
### Added
- Added a mutating `toggle` method to the `Visibility` component
# Objective
Fixes#6244
## Solution
Uses derive to implement `Serialize` and `Deserialize` for `Timer` and `Stopwatch`
### Things to consider
- Should fields such as `finished` and `times_finished_this_tick` in `Timer` be serialized?
- Does `Countdown` and `PrintOnCompletionTimer` need to be serialized and deserialized?
## Changelog
Added `Serialize` and `Deserialize` implementations to `Timer` and `Stopwatch`, `Countdown`.
# Objective
Currently, surprising behavior happens when specifying `#[reflect(...)]` or `#[reflect_value(...)]` multiple times. Rather than merging the traits lists from all attributes, only the trait list from the last attribute is used. For example, in the following code, only the `Debug` and `Hash` traits are reflected and not `Default` or `PartialEq`:
```rs
#[derive(Debug, PartialEq, Hash, Default, Reflect)]
#[reflect(PartialEq, Default)]
#[reflect(Debug, Hash)]
struct Foo;
```
This is especially important when some traits should only be reflected under certain circumstances. For example, this previously had surprisingly behavior when the "serialize" feature is enabled:
```rs
#[derive(Debug, Hash, Reflect)]
#[reflect(Debug, Hash)]
#[cfg_attr(
feature = "serialize",
derive(Serialize, Deserialize),
reflect(Serialize, Deserialize)
]
struct Foo;
```
In addition, compile error messages generated from using the derive macro often point to the `#[derive(Reflect)]` rather than to the source of the error. It would be a lot more helpful if the compiler errors pointed to what specifically caused the error rather than just to the derive macro itself.
## Solution
Merge the trait lists in all `#[reflect(...)]` and `#[reflect_value(...)]` attributes. Additionally, make `#[reflect]` and `#[reflect_value]` mutually exclusive.
Additionally, span information is carried throughout some parts of the code now to ensure that error messages point to more useful places and better indicate what caused those errors. For example, `#[reflect(Hash, Hash)]` points to the second `Hash` as the source of an error. Also, in the following example, the compiler error now points to the `Hash` in `#[reflect(Hash)]` rather than to the derive macro:
```rs
#[derive(Reflect)]
#[reflect(Hash)] // <-- compiler error points to `Hash` for lack of a `Hash` implementation
struct Foo;
```
---
## Changelog
Changed
- Using multiple `#[reflect(...)]` or `#[reflect_value(...)]` attributes now merges the trait lists. For example, `#[reflect(Debug, Hash)] #[reflect(PartialEq, Default)]` is equivalent to `#[reflect(Debug, Hash, PartialEq, Default)]`.
- Multiple `#[reflect(...)]` and `#[reflect_value(...)]` attributes were previously accepted, but only the last attribute was respected.
- Using both `#[reflect(...)]` and `#[reflect_value(...)]` was previously accepted, but had surprising behavior. This is no longer accepted.
- Improved error messages for `#[derive(Reflect)]` by propagating useful span information. Many errors should now point to the source of those errors rather than to the derive macro.
# Objective
Fixes https://github.com/bevyengine/bevy/issues/3418
## Solution
Originally a rebase of https://github.com/bevyengine/bevy/pull/3446. Work was originally done by mfdorst, who should receive considerable credit. Then the error types were extensively reworked by targrub.
## Migration Guide
`AxisSettings` now has a `new()`, which may return an `AxisSettingsError`.
`AxisSettings` fields made private; now must be accessed through getters and setters. There's a dead zone, from `.deadzone_upperbound()` to `.deadzone_lowerbound()`, and a live zone, from `.deadzone_upperbound()` to `.livezone_upperbound()` and from `.deadzone_lowerbound()` to `.livezone_lowerbound()`.
`AxisSettings` setters no longer panic.
`ButtonSettings` fields made private; now must be accessed through getters and setters.
`ButtonSettings` now has a `new()`, which may return a `ButtonSettingsError`.
Co-authored-by: targrub <62773321+targrub@users.noreply.github.com>
