# Objective
- **Describe the objective or issue this PR addresses.**
`bevy_asset` includes code
[here](4350ad0bd1/crates/bevy_asset/src/io/wasm.rs (L61))
that references `web_sys::WorkerGlobalScope`. However, `bevy_asset` does
not enable this feature, see
[here](4350ad0bd1/crates/bevy_asset/Cargo.toml (L50)).
Running examples does not catch this problem because the feature is
implicitly included by `wgpu` when `bevy_render` is also a dependency,
see
[bevy_render](4350ad0bd1/crates/bevy_render/Cargo.toml (L73-L80))
and
[wgpu](3b6112d45d/wgpu/Cargo.toml (L201)).
This results in compile errors for environments that are not using
`bevy_render`.
To reproduce the problem, try to build the crate individually for wasm
targets by running `cargo build -p bevy_asset --target
wasm32-unknown-unknown`.
Running `cargo tree -e features --target wasm32-unknown-unknown` helped
diagnose the issue.
## Solution
- **Describe the solution used to achieve the objective above.**
This PR adds the `WorkerGlobalScope` feature to the `web-sys` portion of
`bevy_asset`'s `Cargo.toml`.
It also seems to be the case that `bevy_asset` no longer needs the
`Request` feature, since no code for `Request` is present anymore. I
confirmed that building the crate individually for wasm succeeds without
the feature, so that change is also included here.
This is a little off-topic, but the repository would probably benefit
from some automation around these types of changes, but I'm not sure
what would work there. For example, building each crate individually for
some key targets would work, but is...well, a lot. Happy to follow up if
there is agreement on a good direction.
## Testing
- **Did you test these changes? If so, how?**
- **How can other people (reviewers) test your changes? Is there
anything specific they need to know?**
Building the crate individually for wasm by running `cargo build -p
bevy_asset --target wasm32-unknown-unknown`.
- **Are there any parts that need more testing?**
I don't believe so.
# Objective
There's a TODO comment above the `AssetMetaCheck` enum mentioning this
should have been done in 0.13
## Solution
Do it in 0.14
## Testing
I've checked that all the asset tests compile. I've also run the
asset_processing and asset_settings tests and they both work.
---
## Changelog
### Changed
-
[`AssetMetaCheck`](https://docs.rs/bevy/latest/bevy/asset/enum.AssetMetaCheck.html)
is no longer a resource and is now a field on the
[`AssetPlugin`](https://docs.rs/bevy/latest/bevy/asset/struct.AssetPlugin.html).
## Migration Guide
Changes to how bevy handles asset meta files now need to be specified
when inserting the `AssetPlugin`.
# Objective
Fixes#12966
## Solution
Renaming multi_threaded feature to match snake case
## Migration Guide
Bevy feature multi-threaded should be refered to multi_threaded from now
on.
# Objective
- `README.md` is a common file that usually gives an overview of the
folder it is in.
- When on <https://crates.io>, `README.md` is rendered as the main
description.
- Many crates in this repository are lacking `README.md` files, which
makes it more difficult to understand their purpose.
<img width="1552" alt="image"
src="https://github.com/bevyengine/bevy/assets/59022059/78ebf91d-b0c4-4b18-9874-365d6310640f">
- There are also a few inconsistencies with `README.md` files that this
PR and its follow-ups intend to fix.
## Solution
- Create a `README.md` file for all crates that do not have one.
- This file only contains the title of the crate (underscores removed,
proper capitalization, acronyms expanded) and the <https://shields.io>
badges.
- Remove the `readme` field in `Cargo.toml` for `bevy` and
`bevy_reflect`.
- This field is redundant because [Cargo automatically detects
`README.md`
files](https://doc.rust-lang.org/cargo/reference/manifest.html#the-readme-field).
The field is only there if you name it something else, like `INFO.md`.
- Fix capitalization of `bevy_utils`'s `README.md`.
- It was originally `Readme.md`, which is inconsistent with the rest of
the project.
- I created two commits renaming it to `README.md`, because Git appears
to be case-insensitive.
- Expand acronyms in title of `bevy_ptr` and `bevy_utils`.
- In the commit where I created all the new `README.md` files, I
preferred using expanded acronyms in the titles. (E.g. "Bevy Developer
Tools" instead of "Bevy Dev Tools".)
- This commit changes the title of existing `README.md` files to follow
the same scheme.
- I do not feel strongly about this change, please comment if you
disagree and I can revert it.
- Add <https://shields.io> badges to `bevy_time` and `bevy_transform`,
which are the only crates currently lacking them.
---
## Changelog
- Added `README.md` files to all crates missing it.
# Objective
- Fixes#13024.
## Solution
- Run `cargo clippy --target wasm32-unknown-unknown` until there are no
more errors.
- I recommend reviewing one commit at a time :)
---
## Changelog
- Fixed Clippy lints for `wasm32-unknown-unknown` target.
- Updated `bevy_transform`'s `README.md`.
# Objective
As described in #12467, Bevy does not have any spans for any of the
tasks scheduled onto the IO and async compute task pools.
## Solution
Instrument all asset loads and asset processing. Since this change is
restricted to asset tasks, it does not completely solve #12467, but it
does mean we can record the asset path in the trace.
![image](https://github.com/bevyengine/bevy/assets/8494645/59faee63-1f69-40af-bf47-312c4d67d1e2)
---
## Changelog
Tracing will now include spans for asset loading and asset processing.
# Objective
- Fixes#12976
## Solution
This one is a doozy.
- Run `cargo +beta clippy --workspace --all-targets --all-features` and
fix all issues
- This includes:
- Moving inner attributes to be outer attributes, when the item in
question has both inner and outer attributes
- Use `ptr::from_ref` in more scenarios
- Extend the valid idents list used by `clippy:doc_markdown` with more
names
- Use `Clone::clone_from` when possible
- Remove redundant `ron` import
- Add backticks to **so many** identifiers and items
- I'm sorry whoever has to review this
---
## Changelog
- Added links to more identifiers in documentation.
# Objective
A help thread on discord asked how to use signed URLs for assets. This
currently fails because the query parameters are included in the
extension, which causes no suitable loader to be found:
```
Failed to load asset 'http://localhost:4566/dev/1711921849174.jpeg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=%2F20240331%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240331T230145Z&X-Amz-Expires=900&X-Amz-Signature=64855e731c279fa01063568e37095562ef74e09387c881bd3e3604181d0cc108&X-Amz-SignedHeaders=host&x-id=GetObject' with asset loader 'bevy_render::texture::image_loader::ImageLoader':
Could not load texture file: Error reading image file localhost:4566/dev/1711921849174.jpeg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=%2F20240331%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240331T230145Z&X-Amz-Expires=900&X-Amz-Signature=64855e731c279fa01063568e37095562ef74e09387c881bd3e3604181d0cc108&X-Amz-SignedHeaders=host&x-id=GetObject: invalid image extension: jpeg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=%2F20240331%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240331T230145Z&X-Amz-Expires=900&X-Amz-Signature=64855e731c279fa01063568e37095562ef74e09387c881bd3e3604181d0cc108&X-Amz-SignedHeaders=host&x-id=GetObject, this is an error in `bevy_render`.
```
## Solution
Make `get_full_extension` remove everything after the first `?`
character.
If this is accepted then it should also be documented in `AssetPath`
that extensions cannot include question marks.
An alternative is to special case this handling only for wasm, but that
would be annoying for the
[bevy_web_asset](https://github.com/johanhelsing/bevy_web_asset) plugin,
and in my opinion also just more confusing overall.
# Objective
This is a necessary precursor to #9122 (this was split from that PR to
reduce the amount of code to review all at once).
Moving `!Send` resource ownership to `App` will make it unambiguously
`!Send`. `SubApp` must be `Send`, so it can't wrap `App`.
## Solution
Refactor `App` and `SubApp` to not have a recursive relationship. Since
`SubApp` no longer wraps `App`, once `!Send` resources are moved out of
`World` and into `App`, `SubApp` will become unambiguously `Send`.
There could be less code duplication between `App` and `SubApp`, but
that would break `App` method chaining.
## Changelog
- `SubApp` no longer wraps `App`.
- `App` fields are no longer publicly accessible.
- `App` can no longer be converted into a `SubApp`.
- Various methods now return references to a `SubApp` instead of an
`App`.
## Migration Guide
- To construct a sub-app, use `SubApp::new()`. `App` can no longer
convert into `SubApp`.
- If you implemented a trait for `App`, you may want to implement it for
`SubApp` as well.
- If you're accessing `app.world` directly, you now have to use
`app.world()` and `app.world_mut()`.
- `App::sub_app` now returns `&SubApp`.
- `App::sub_app_mut` now returns `&mut SubApp`.
- `App::get_sub_app` now returns `Option<&SubApp>.`
- `App::get_sub_app_mut` now returns `Option<&mut SubApp>.`
# Objective
For some asset loaders, it can be useful not to read the entire asset
file and just read a specific region of a file. For this, we need a way
to seek at a specific position inside the file
## Solution
I added support for `AsyncSeek` to `Reader`. In my case, I want to only
read a part of a file, and for that I need to seek to a specific point.
## Migration Guide
Every custom reader (which previously only needed the `AsyncRead` trait
implemented) now also needs to implement the `AsyncSeek` trait to add
the seek capability.
## Problem
- A mutable borrow of a handle cannot be directly turned into an AssetId
with `.into()`. You must do a reborrow `&*my_handle`.
## Solution
- Add an impl for From<&mut Handle> to AssetId and UntypedAssetId.
# Objective
Resolves#3824. `unsafe` code should be the exception, not the norm in
Rust. It's obviously needed for various use cases as it's interfacing
with platforms and essentially running the borrow checker at runtime in
the ECS, but the touted benefits of Bevy is that we are able to heavily
leverage Rust's safety, and we should be holding ourselves accountable
to that by minimizing our unsafe footprint.
## Solution
Deny `unsafe_code` workspace wide. Add explicit exceptions for the
following crates, and forbid it in almost all of the others.
* bevy_ecs - Obvious given how much unsafe is needed to achieve
performant results
* bevy_ptr - Works with raw pointers, even more low level than bevy_ecs.
* bevy_render - due to needing to integrate with wgpu
* bevy_window - due to needing to integrate with raw_window_handle
* bevy_utils - Several unsafe utilities used by bevy_ecs. Ideally moved
into bevy_ecs instead of made publicly usable.
* bevy_reflect - Required for the unsafe type casting it's doing.
* bevy_transform - for the parallel transform propagation
* bevy_gizmos - For the SystemParam impls it has.
* bevy_assets - To support reflection. Might not be required, not 100%
sure yet.
* bevy_mikktspace - due to being a conversion from a C library. Pending
safe rewrite.
* bevy_dynamic_plugin - Inherently unsafe due to the dynamic loading
nature.
Several uses of unsafe were rewritten, as they did not need to be using
them:
* bevy_text - a case of `Option::unchecked` could be rewritten as a
normal for loop and match instead of an iterator.
* bevy_color - the Pod/Zeroable implementations were replaceable with
bytemuck's derive macros.
# Objective
This PR fixes#12125
## Solution
The logic in this PR was borrowed from gloo-net and essentially probes
the global Javascript context to see if we are in a window or a worker
before calling `fetch_with_str`.
---------
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
Currently the built docs only shows the logo and favicon for the top
level `bevy` crate. This makes views like
https://docs.rs/bevy_ecs/latest/bevy_ecs/ look potentially unrelated to
the project at first glance.
## Solution
Reproduce the docs attributes for every crate that Bevy publishes.
Ideally this would be done with some workspace level Cargo.toml control,
but AFAICT, such support does not exist.
# Objective
get_asset_paths tries to check whether a folder is empty, and if so
delete it. However rather than checking whether any subfolder contains
files it checks whether _all_ subfolders have files.
Also cleanup various BoxedFutures in async recursive functions like
these, rust 1.77 now allows recursive async functions (albeit still by
boxing), hurray! This is a followup to #12550 (sorta). More BoxedFuture
stuff can be removed now that rust 1.77 is out, which can use async
recursive functions! This is mainly just cleaner code wise - the
recursion still boxes the future so not much to win there.
PR is mainly whitespace changes so do disable whitespace diffs for
easier review.
# Objective
* Adopted #12025 to fix merge conflicts
* In some cases we used manual impls for certain types, though they are
(at least, now) unnecessary.
## Solution
* Use macros and reflecting-by-value to avoid this clutter.
* Though there were linker issues with Reflect and the CowArc in
AssetPath (see https://github.com/bevyengine/bevy/issues/9747), I
checked these are resolved by using #[reflect_value].
---------
Co-authored-by: soqb <cb.setho@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: James Liu <contact@jamessliu.com>
Fixes#12600
## Solution
Removed Into<AssetId<T>> for Handle<T> as proposed in Issue
conversation, fixed dependent code
## Migration guide
If you use passing Handle by value as AssetId, you should pass reference
or call .id() method on it
Before (0.13):
`assets.insert(handle, value);`
After (0.14):
`assets.insert(&handle, value);`
or
`assets.insert(handle.id(), value);`
# Objective
- It can be useful to have access to the path of the current asset being
processed, for example if you want to need a second file that is
relative to the current file being processed.
## Solution
- I added a `path()` function to the `ProcessContext`
# Objective
Lets say I have the following `.meta` file:
```RON
(
meta_format_version: "1.0",
asset: Ignore,
)
```
When a file is inside the `assets` directory and processing is enabled,
the processor will copy the file into `imported_assets` although it
should be ignored and therefore not copied.
## Solution
- I added a simple check that does not copy the assets if the
AssetAction is `Ignore`.
## Migration Guide
- The public `ProcessResult` enum now has a `ProcessResult::Ignore`
variant that must be handled.
# Objective
Fix Pr CI failing over dead code in tests and main branch CI failing
over a missing semicolon. Fixes#12620.
## Solution
Add dead_code annotations and a semicolon.
# Objective
Simplify implementing some asset traits without Box::pin(async move{})
shenanigans.
Fixes (in part) https://github.com/bevyengine/bevy/issues/11308
## Solution
Use async-fn in traits when possible in all traits. Traits with return
position impl trait are not object safe however, and as AssetReader and
AssetWriter are both used with dynamic dispatch, you need a Boxed
version of these futures anyway.
In the future, Rust is [adding
](https://blog.rust-lang.org/2023/12/21/async-fn-rpit-in-traits.html)proc
macros to generate these traits automatically, and at some point in the
future dyn traits should 'just work'. Until then.... this seemed liked
the right approach given more ErasedXXX already exist, but, no clue if
there's plans here! Especially since these are public now, it's a bit of
an unfortunate API, and means this is a breaking change.
In theory this saves some performance when these traits are used with
static dispatch, but, seems like most code paths go through dynamic
dispatch, which boxes anyway.
I also suspect a bunch of the lifetime annotations on these function
could be simplified now as the BoxedFuture was often the only thing
returned which needed a lifetime annotation, but I'm not touching that
for now as traits + lifetimes can be so tricky.
This is a revival of
[pull/11362](https://github.com/bevyengine/bevy/pull/11362) after a
spectacular merge f*ckup, with updates to the latest Bevy. Just to recap
some discussion:
- Overall this seems like a win for code quality, especially when
implementing these traits, but a loss for having to deal with ErasedXXX
variants.
- `ConditionalSend` was the preferred name for the trait that might be
Send, to deal with wasm platforms.
- When reviewing be sure to disable whitespace difference, as that's 95%
of the PR.
## Changelog
- AssetReader, AssetWriter, AssetLoader, AssetSaver and Process now use
async-fn in traits rather than boxed futures.
## Migration Guide
- Custom implementations of AssetReader, AssetWriter, AssetLoader,
AssetSaver and Process should switch to async fn rather than returning a
bevy_utils::BoxedFuture.
- Simultaniously, to use dynamic dispatch on these traits you should
instead use dyn ErasedXXX.
# Objective
fix#12344
## Solution
use existing machinery in track_assets to determine if the asset is
unused before firing Asset::Unused event
~~most extract functions use `AssetEvent::Removed` to schedule deletion
of render world resources. `RenderAssetPlugin` was using
`AssetEvent::Unused` instead.
`Unused` fires when the last strong handle is dropped, even if a new one
is created. `Removed` only fires when a new one is not created.
as far as i can see, `Unused` is the same as `Removed` except for this
"feature", and that it also fires early if all handles for a loading
asset are dropped (`Removed` fires after the loading completes). note
that in that case, processing based on `Loaded` won't have been done
anyway.
i think we should get rid of `Unused` completely, it is not currently
used anywhere (except here, previously) and i think using it is probably
always a mistake.
i also am not sure why we keep loading assets that have been dropped
while loading, we should probably drop the loader task as well and
remove immediately.~~
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/12380
## Solution
- Before #11986 AssetEvents were scheduled after PostUpdate. That pr
moved these into First. This PR moves them into Last which is closer to
how they were scheduled before.
# Objective
Fix missing `TextBundle` (and many others) which are present in the main
crate as default features but optional in the sub-crate. See:
- https://docs.rs/bevy/0.13.0/bevy/ui/node_bundles/index.html
- https://docs.rs/bevy_ui/0.13.0/bevy_ui/node_bundles/index.html
~~There are probably other instances in other crates that I could track
down, but maybe "all-features = true" should be used by default in all
sub-crates? Not sure.~~ (There were many.) I only noticed this because
rust-analyzer's "open docs" features takes me to the sub-crate, not the
main one.
## Solution
Add "all-features = true" to docs.rs metadata for crates that use
features.
## Changelog
### Changed
- Unified features documented on docs.rs between main crate and
sub-crates
This is an implementation of RFC #51:
https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md
Note that the implementation strategy is different from the one outlined
in that RFC, because two-phase animation has now landed.
# Objective
Bevy needs animation blending. The RFC for this is [RFC 51].
## Solution
This is an implementation of the RFC. Note that the implementation
strategy is different from the one outlined there, because two-phase
animation has now landed.
This is just a draft to get the conversation started. Currently we're
missing a few things:
- [x] A fully-fleshed-out mechanism for transitions
- [x] A serialization format for `AnimationGraph`s
- [x] Examples are broken, other than `animated_fox`
- [x] Documentation
---
## Changelog
### Added
* The `AnimationPlayer` has been reworked to support blending multiple
animations together through an `AnimationGraph`, and as such will no
longer function unless a `Handle<AnimationGraph>` has been added to the
entity containing the player. See [RFC 51] for more details.
* Transition functionality has moved from the `AnimationPlayer` to a new
component, `AnimationTransitions`, which works in tandem with the
`AnimationGraph`.
## Migration Guide
* `AnimationPlayer`s can no longer play animations by themselves and
need to be paired with a `Handle<AnimationGraph>`. Code that was using
`AnimationPlayer` to play animations will need to create an
`AnimationGraph` asset first, add a node for the clip (or clips) you
want to play, and then supply the index of that node to the
`AnimationPlayer`'s `play` method.
* The `AnimationPlayer::play_with_transition()` method has been removed
and replaced with the `AnimationTransitions` component. If you were
previously using `AnimationPlayer::play_with_transition()`, add all
animations that you were playing to the `AnimationGraph`, and create an
`AnimationTransitions` component to manage the blending between them.
[RFC 51]:
https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md
---------
Co-authored-by: Rob Parrett <robparrett@gmail.com>
# Objective
Make bevy_utils less of a compilation bottleneck. Tackle #11478.
## Solution
* Move all of the directly reexported dependencies and move them to
where they're actually used.
* Remove the UUID utilities that have gone unused since `TypePath` took
over for `TypeUuid`.
* There was also a extraneous bytemuck dependency on `bevy_core` that
has not been used for a long time (since `encase` became the primary way
to prepare GPU buffers).
* Remove the `all_tuples` macro reexport from bevy_ecs since it's
accessible from `bevy_utils`.
---
## Changelog
Removed: Many of the reexports from bevy_utils (petgraph, uuid, nonmax,
smallvec, and thiserror).
Removed: bevy_core's reexports of bytemuck.
## Migration Guide
bevy_utils' reexports of petgraph, uuid, nonmax, smallvec, and thiserror
have been removed.
bevy_core' reexports of bytemuck's types has been removed.
Add them as dependencies in your own crate instead.
# Objective
Fix#12304. Remove unnecessary type registrations thanks to #4154.
## Solution
Conservatively remove type registrations. Keeping the top level
components, resources, and events, but dropping everything else that is
a type of a member of those types.
# Objective
`bevy_utils::Entry` is only useful when using
`BuildHasherDefault<AHasher>`. It would be great if we didn't have to
write out `bevy_utils::hashbrown::hash_map::Entry` whenever we want to
use a different `BuildHasher`, such as when working with
`bevy_utils::TypeIdMap`.
## Solution
Give `bevy_utils::Entry` a new optional type parameter for defining a
custom `BuildHasher`, such as `NoOpHash`. This parameter defaults to
`BuildHasherDefault<AHasher>`— the `BuildHasher` used by
`bevy_utils::HashMap`.
---
## Changelog
- Added an optional third type parameter to `bevy_utils::Entry` to
specify a custom `BuildHasher`
# Objective
Fixes#11298. Make the use of bevy_log vs bevy_utils::tracing more
consistent.
## Solution
Replace all uses of bevy_log's logging macros with the reexport from
bevy_utils. Remove bevy_log as a dependency where it's no longer needed
anymore.
Ideally we should just be using tracing directly, but given that all of
these crates are already using bevy_utils, this likely isn't that great
of a loss right now.
# Objective
`FromWorld` is often used to group loading and creation of assets for
resources.
With this setup, users often end up repetitively calling
`.resource::<AssetServer>` and `.resource_mut::<Assets<T>>`, and may
have difficulties handling lifetimes of the returned references.
## Solution
Add extension methods to `World` to add and load assets, through a new
extension trait defined in `bevy_asset`.
### Other considerations
* This might be a bit too "magic", as it makes implicit the resource
access.
* We could also implement `DirectAssetAccessExt` on `App`, but it didn't
feel necessary, as `FromWorld` is the principal use-case here.
---
## Changelog
* Add the `DirectAssetAccessExt` trait, which adds the `add_asset`,
`load_asset` and `load_asset_with_settings` method to the `World` type.
# Objective
The `AssetIndex` cannot be carried across boundaries that do not allow
explicit rust types.
For context, I ran into this issue while trying to implent an
improvement for bevy_egui which leverages the not-so-new custom loader
API. Passing through a handle directly isn't possible, but instead it
requires stringified URI s. I had to work around the lack of this API s
existance using reflection, which is rather dirty.
## Solution
- Add `to_bits` and `from_bits` functions to `AssetIndex` to allow
moving this type through such boundaries.
---------
Co-authored-by: Rob Parrett <robparrett@gmail.com>
# Objective
Memory usage optimisation
## Solution
`HashMap` and `HashSet`'s keys are immutable. So using mutable types
like `String`, `Vec<T>`, or `PathBuf` as a key is a waste of memory:
they have an extra `usize` for their capacity and may have spare
capacity.
This PR replaces these types by their immutable equivalents `Box<str>`,
`Box<[T]>`, and `Box<Path>`.
For more context, I recommend watching the [Use Arc Instead of
Vec](https://www.youtube.com/watch?v=A4cKi7PTJSs) video.
---------
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
Fix#11845.
## Solution
Remove the `UpdateAssets` and `AssetEvents` schedules. Moved the
`UpdateAssets` systems to `PreUpdate`, and `AssetEvents` systems into
`First`. The former is meant to run before any of the event flushes.
## Future Work
It'd be ideal if we could manually flush the events for assets to avoid
needing two, sort of redundant, systems. This should at least let them
potentially run in parallel with all of the systems in the schedules
they were moved to.
---
## Changelog
Removed: `UpdateAssets` schedule from the main schedule. All systems
have been moved to `PreUpdate`.
Removed: `AssetEvents` schedule from the main schedule. All systems have
been move to `First` with the same system sets.
## Migration Guide
TODO
# Objective
- I hit an issue using the `file_watcher` feature to hot reload assets
for my game. The change in this PR allows me to now hot reload assets.
- The issue stemmed from my project being a multi crate workspace
project structured like so:
```
└── my_game
├── my_game_core
│ ├── src
│ └── assets
├── my_game_editor
│ └── src/main.rs
└── my_game
└── src/main.rs
```
- `my_game_core` is a crate that holds all my game logic and assets
- `my_game` is the crate that creates the binary for my game (depends on
the game logic and assets in `my_game_core`)
- `my_game_editor` is an editor tool for my game (it also depends on the
game logic and assets in `my_game_core`)
Whilst running `my_game` and `my_game_editor` from cargo during
development I would use `AssetPlugin` like so:
```rust
default_plugins.set(AssetPlugin {
watch_for_changes_override: Some(true),
file_path: "../my_game_core/assets".to_string(),
..Default::default()
})
```
This works fine; bevy picks up the assets. However on saving an asset I
would get the following panic from `file_watcher`. It wouldn't kill the
app, but I wouldn't see the asset hot reload:
```
thread 'notify-rs debouncer loop' panicked at /Users/ian/.cargo/registry/src/index.crates.io-6f17d22bba15001f/bevy_asset-0.12.1/src/io/file/file_watcher.rs:48:58:
called `Result::unwrap()` on an `Err` value: StripPrefixError(())
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```
## Solution
- The solution is to collapse dot segments in the root asset path
`FileWatcher` is using
- There was already bevy code to do this in `AssetPath`, so I extracted
that code so it could be reused in `FileWatcher`
# Objective
- Sometimes, it is useful to get a `Handle<T>` from an `AssetId<T>`. For
example, when iterating `Assets` to find a specific asset. So much so
that it's possible to do so with `AssetServer::get_id_handle`
- However, `AssetServer::get_id_handle` doesn't work with assets
directly added to `Assets` using `Assets::add`.
- Fixes#12087
## Solution
- Add `Assets::get_strong_handle` to convert an `AssetId` into an
`Handle`
- Document `AssetServer::get_id_handle` to explain its limitation and
point to `get_strong_handle`.
- Add a test for `get_strong_handle`
- Add a `duplicate_handles` field to `Assets` to avoid dropping assets
with a live handle generated by `get_strong_handle` (more reference
counting yay…)
- Fix typos in `Assets` docs
---
## Changelog
- Add `Assets::get_strong_handle` to convert an `AssetId` into an
`Handle`
# Objective
When dealing with custom asset sources it can be a bit tricky to get
asset roots combined with relative paths correct.
It's even harder when it isn't mentioned which path was problematic.
## Solution
Mention which path failed for the file watcher.
Signed-off-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
Co-authored-by: Torstein Grindvik <torstein.grindvik@muybridge.com>
# Objective
- The file asset source currently creates the `imported_assets/Default`
directory with relative path, which leads to wrongly created directories
when the executable is run with a working directory different from the
project root.
## Solution
- Use the full path instead.
Fixes#12016.
Bump version after release
This PR has been auto-generated
Co-authored-by: Bevy Auto Releaser <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: François <mockersf@gmail.com>
# Objective
The derive macro wasn't doc-commented, so it showed up in the generated
doc as follow:
```rust
#[derive(Asset, TypePath)]
let shader = asset_server.load::<Shader>("embedded://bevy_rock/render/rock.wgsl");
```
Which is very confusing
## Solution
Comment the `derive` attribute as well
# Objective
Right now, if you call `embedded_asset` with 2 arguments as a qualified
path it doesn't work (`bevy::asset::embedded_asset!(app, "foo.wgsl")` ->
"cannot find macro `embedded_asset` in this scope")
## Solution
Use `$crate::` in expansion for 2-arg case.
# Objective
When registering and preregistering asset loaders, there would be a
`warn!` if multiple asset loaders use a given extension, and an `info!`
if multiple asset loaders load the same asset type. Since both of these
situations are individually fine, it was decided that these messages
should be removed.
## Solution
Replace both of these messages with a new `warn!` that notes that if
multiple asset loaders share the same asset type _and_ share extensions,
that the loader must be specified in the `.meta` file for those assets
in order to solve the ambiguity. This is a more useful message, since it
notes when a user must take special action / consideration.
# Objective
- Fixes#11638
- See
[here](https://github.com/bevyengine/bevy/issues/11638#issuecomment-1920508465)
for details on the cause of this issue.
## Solution
- Modified `AssetLoaders` to capture possibility of multiple
`AssetLoader` registrations operating on the same `Asset` type, but
different extensions.
- Added an algorithm which will attempt to resolve via `AssetLoader`
name, then `Asset` type, then by extension. If at any point multiple
loaders fit a particular criteria, the next criteria is used as a tie
breaker.
# Objective
Scheduling low cost systems has significant overhead due to task pool
contention and the extra machinery to schedule and run them. Following
the example of #7728, `asset_events` is good example of this kind of
system, where there is no work to be done when there are no queued asset
events.
## Solution
Put a run condition on it that checks if there are any queued events.
## Performance
Tested against `many_foxes`, we can see a slight improvement in the
total time spent in `UpdateAssets`. Also noted much less volatility due
to not being at the whim of the OS thread scheduler.
![image](https://github.com/bevyengine/bevy/assets/3137680/e0b282bf-27d0-4fe4-81b9-ecd72ab258e5)
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fix https://github.com/bevyengine/bevy/issues/11657
## Solution
Add a `ReflectKind` enum, add `Reflect::reflect_kind` which returns a
`ReflectKind`, and add `kind` method implementions to `ReflectRef`,
`ReflectMut`, and `ReflectOwned`, which returns a `ReflectKind`.
I also changed `AccessError` to use this new struct instead of it's own
`TypeKind` struct.
---
## Changelog
- Added `ReflectKind`, an enumeration over the kinds of a reflected type
without its data.
- Added `Reflect::reflect_kind` (with default implementation)
- Added implementation for the `kind` method on `ReflectRef`,
`ReflectMut`, and `ReflectOwned` which gives their kind without any
information, as a `ReflectKind`
Use `TypeIdMap<T>` instead of `HashMap<TypeId, T>`
- ~~`TypeIdMap` was in `bevy_ecs`. I've kept it there because of
#11478~~
- ~~I haven't swapped `bevy_reflect` over because it doesn't depend on
`bevy_ecs`, but I'd also be happy with moving `TypeIdMap` to
`bevy_utils` and then adding a dependency to that~~
- ~~this is a slight change in the public API of
`DrawFunctionsInternal`, does this need to go in the changelog?~~
## Changelog
- moved `TypeIdMap` to `bevy_utils`
- changed `DrawFunctionsInternal::indices` to `TypeIdMap`
## Migration Guide
- `TypeIdMap` now lives in `bevy_utils`
- `DrawFunctionsInternal::indices` now uses a `TypeIdMap`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Currently the `missing_docs` lint is allowed-by-default and enabled at
crate level when their documentations is complete (see #3492).
This PR proposes to inverse this logic by making `missing_docs`
warn-by-default and mark crates with imcomplete docs allowed.
## Solution
Makes `missing_docs` warn at workspace level and allowed at crate level
when the docs is imcomplete.
# Objective
- `AssetTransformer` provides an input asset, and output an asset, but
provides no access to the `LabeledAsset`'s created by the `AssetLoader`.
Labeled sub assets are an extremely important piece of many assets, Gltf
in particular, and without them the amount of transformation on an asset
is limited. In order for `AssetTransformer`'s to be useful, they need to
have access to these sub assets.
- LabeledAsset's loaded by `AssetLoader`s are provided to `AssetSaver`s
in the `LoadAndSave` process, but the `LoadTransformAndSave` process
drops these values in the transform stage, and so `AssetSaver` is given
none.
- Fixes#11606
Ideally the AssetTransformer should not ignore labeled sub assets, and
they should be kept at least for the AssetSaver
## Solution
- I created a new struct similar to `SavedAsset` named
`TransformedAsset` which holds the input asset, and the HashMap of
`LabeledAsset`s. The transform function now takes as input a
`TransformedAsset`, and returns a `TransformedAsset::<AssetOutput>`.
This gives the transform function access to the labeled sub assets
created by the `AssetLoader`.
- I also created `TransformedSubAsset` which holds mutable references to
a sub asset and that sub assets HashMap of `LabeledAsset`s. This allows
you to travers the Tree of `LabeledAsset`s by reference relatively
easily.
- The `LoadTransformAndSave` processor was then reworked to use the new
structs, stopping the `LabeledAsset`s from being dropped.
---
## Changelog
- Created TransformedAsset struct and TransformedSubAsset struct.
- Changed `get_untyped_handle` to return a `UntypedHandle` directly
rather than a reference and added `get_handle` as a typed variant in
SavedAsset and TransformedAsset
- Added `SavedAsset::from_transformed` as a constructor from a
`TransformedAsset`
- Switched LoadTransformAndSave process code to work with new
`TransformedAsset` type
- Added a `ProcessError` for `AssetTransformer` in process.rs
- Switched `AssetTransformer::transform` to use `TransformedAsset` as
input and output.
- Switched `AssetTransformer` to use a `BoxedFuture` like `AssetLoader`
and `AssetSaver` to allow for async transformation code.
- Updated AssetTransformer example to use new structure.
# Objective
- Addresses **Support processing and loading files without extensions**
from #9714
- Addresses **More runtime loading configuration** from #9714
- Fixes#367
- Fixes#10703
## Solution
`AssetServer::load::<A>` and `AssetServer::load_with_settings::<A>` can
now use the `Asset` type parameter `A` to select a registered
`AssetLoader` without inspecting the provided `AssetPath`. This change
cascades onto `LoadContext::load` and `LoadContext::load_with_settings`.
This allows the loading of assets which have incorrect or ambiguous file
extensions.
```rust
// Allow the type to be inferred by context
let handle = asset_server.load("data/asset_no_extension");
// Hint the type through the handle
let handle: Handle<CustomAsset> = asset_server.load("data/asset_no_extension");
// Explicit through turbofish
let handle = asset_server.load::<CustomAsset>("data/asset_no_extension");
```
Since a single `AssetPath` no longer maps 1:1 with an `Asset`, I've also
modified how assets are loaded to permit multiple asset types to be
loaded from a single path. This allows for two different `AssetLoaders`
(which return different types of assets) to both load a single path (if
requested).
```rust
// Uses GltfLoader
let model = asset_server.load::<Gltf>("cube.gltf");
// Hypothetical Blob loader for data transmission (for example)
let blob = asset_server.load::<Blob>("cube.gltf");
```
As these changes are reflected in the `LoadContext` as well as the
`AssetServer`, custom `AssetLoaders` can also take advantage of this
behaviour to create more complex assets.
---
## Change Log
- Updated `custom_asset` example to demonstrate extension-less assets.
- Added `AssetServer::get_handles_untyped` and Added
`AssetServer::get_path_ids`
## Notes
As a part of that refactor, I chose to store `AssetLoader`s (within
`AssetLoaders`) using a `HashMap<TypeId, ...>` instead of a `Vec<...>`.
My reasoning for this was I needed to add a relationship between `Asset`
`TypeId`s and the `AssetLoader`, so instead of having a `Vec` and a
`HashMap`, I combined the two, removing the `usize` index from the
adjacent maps.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- SavedAsset's iter_labels returns ```&str```, however accessing
LabeledAssets requires ```CowArc<'static, str>```
- Although SavedAsset holds UntypedHandles in its hashmap of
LabeledAssets, they are inaccessible as LabeledAssets are casted to
SavedAsset or ErasedLoadedAsset, which don't contain their
UntypedHandles
- Adresses #11609
## Solution
- Used Trait bounds to allow for either ```CowArc<'static, str>``` or
```&str``` to be used as a label in get_labeled and get_erased_labeled.
- Added method get_untyped_handle to get UntypedHandle from the
LabeledAsset.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Revert the changes to type parameter bounds introduced in #9046,
improves the `#[reflect(where)]` attribute (also from #9046), and adds
the ability to opt out of field bounds.
This is based on suggestions by @soqb and discussion on
[Discord](https://discord.com/channels/691052431525675048/1002362493634629796/1201227833826103427).
## Solution
Reverts the changes to type parameter bounds when deriving `Reflect`,
introduced in #9046. This was originally done as a means of fixing a
recursion issue (#8965). However, as @soqb pointed out, we could achieve
the same result by simply making an opt-out attribute instead of messing
with the type parameter bounds.
This PR has four main changes:
1. Reverts the type parameter bounds from #9046
2. Includes `TypePath` as a default bound for active fields
3. Changes `#reflect(where)]` to be strictly additive
4. Adds `#reflect(no_field_bounds)]` to opt out of field bounds
Change 1 means that, like before, type parameters only receive at most
the `TypePath` bound (if `#[reflect(type_path = false)]` is not present)
and active fields receive the `Reflect` or `FromReflect` bound. And with
Change 2, they will also receive `TypePath` (since it's indirectly
required by `Typed` to construct `NamedField` and `UnnamedField`
instances).
Change 3 was made to make room for Change 4. By splitting out the
responsibility of `#reflect(where)]`, we can use it with or without
`#reflect(no_field_bounds)]` for various use cases.
For example, if we hadn't done this, the following would have failed:
```rust
// Since we're not using `#reflect(no_field_bounds)]`,
// `T::Assoc` is automatically given the required bounds
// of `FromReflect + TypePath`
#[derive(Reflect)]
#[reflect(where T::Assoc: OtherTrait)]
struct Foo<T: MyTrait> {
value: T::Assoc,
}
```
This provides more flexibility to the user while still letting them add
or remove most trait bounds.
And to solve the original recursion issue, we can do:
```rust
#[derive(Reflect)]
#[reflect(no_field_bounds)] // <-- Added
struct Foo {
foo: Vec<Foo>
}
```
#### Bounds
All in all, we now have four sets of trait bounds:
- `Self` gets the bounds `Any + Send + Sync`
- Type parameters get the bound `TypePath`. This can be opted out of
with `#[reflect(type_path = false)]`
- Active fields get the bounds `TypePath` and `FromReflect`/`Reflect`
bounds. This can be opted out of with `#reflect(no_field_bounds)]`
- Custom bounds can be added with `#[reflect(where)]`
---
## Changelog
- Revert some changes #9046
- `#reflect(where)]` is now strictly additive
- Added `#reflect(no_field_bounds)]` attribute to opt out of automatic
field trait bounds when deriving `Reflect`
- Made the `TypePath` requirement on fields when deriving `Reflect` more
explicit
## Migration Guide
> [!important]
> This PR shouldn't be a breaking change relative to the current version
of Bevy (v0.12). And since it removes the breaking parts of #9046, that
PR also won't need a migration guide.
# Objective
- Closes#11490.
- Allow retrieving the current asset watch behavior from the
`AssetServer`.
## Solution
- Add the corresponding getter. (also fixes some trailing whitespace).
A corresponding helper could also be added on the `AssetPlugin` struct
(returning `self.watch_for_changes_override.unwrap_or(cfg!(feature =
"watch"))`), but it seems it isn't a current practice to have actual
methods on the plugin structs appart from the `Plugin` impl.
---
## Changelog
### Added
Added `watching_for_changes` getter on `AssetServer`.
---------
Co-authored-by: Mateusz Wachowiak <mateusz_wachowiak@outlook.com>
# Objective
Fixes#8965.
#### Background
For convenience and to ensure everything is setup properly, we
automatically add certain bounds to the derived types. The current
implementation does this by taking the types from all active fields and
adding them to the where-clause of the generated impls. I believe this
method was chosen because it won't add bounds to types that are
otherwise ignored.
```rust
#[derive(Reflect)]
struct Foo<T, U: SomeTrait, V> {
t: T,
u: U::Assoc,
#[reflect(ignore)]
v: [V; 2]
}
// Generates something like:
impl<T, U: SomeTrait, V> for Foo<T, U, V>
where
// Active:
T: Reflect,
U::Assoc: Reflect,
// Ignored:
[V; 2]: Send + Sync + Any
{
// ...
}
```
The self-referential type fails because it ends up using _itself_ as a
type bound due to being one of its own active fields.
```rust
#[derive(Reflect)]
struct Foo {
foo: Vec<Foo>
}
// Foo where Vec<Foo>: Reflect -> Vec<T> where T: Reflect -> Foo where Vec<Foo>: Reflect -> ...
```
## Solution
We can't simply parse all field types for the name of our type. That
would be both complex and prone to errors and false-positives. And even
if it wasn't, what would we replace the bound with?
Instead, I opted to go for a solution that only adds the bounds to what
really needs it: the type parameters. While the bounds on concrete types
make errors a bit cleaner, they aren't strictly necessary. This means we
can change our generated where-clause to only add bounds to generic type
parameters.
Doing this, though, returns us back to the problem of over-bounding
parameters that don't need to be bounded. To solve this, I added a new
container attribute (based on
[this](https://github.com/dtolnay/syn/issues/422#issuecomment-406882925)
comment and @nicopap's
[comment](https://github.com/bevyengine/bevy/pull/9046#issuecomment-1623593780))
that allows us to pass in a custom where clause to modify what bounds
are added to these type parameters.
This allows us to do stuff like:
```rust
trait Trait {
type Assoc;
}
// We don't need `T` to be reflectable since we only care about `T::Assoc`.
#[derive(Reflect)]
#[reflect(where T::Assoc: FromReflect)]
struct Foo<T: Trait>(T::Assoc);
#[derive(TypePath)]
struct Bar;
impl Trait for Bar {
type Assoc = usize;
}
#[derive(Reflect)]
struct Baz {
a: Foo<Bar>,
}
```
> **Note**
> I also
[tried](dc139ea34c)
allowing `#[reflect(ignore)]` to be used on the type parameters
themselves, but that proved problematic since the derive macro does not
consume the attribute. This is why I went with the container attribute
approach.
### Alternatives
One alternative could possibly be to just not add reflection bounds
automatically (i.e. only add required bounds like `Send`, `Sync`, `Any`,
and `TypePath`).
The downside here is we add more friction to using reflection, which
already comes with its own set of considerations. This is a potentially
viable option, but we really need to consider whether or not the
ergonomics hit is worth it.
If we did decide to go the more manual route, we should at least
consider something like #5772 to make it easier for users to add the
right bounds (although, this could still become tricky with
`FromReflect` also being automatically derived).
### Open Questions
1. Should we go with this approach or the manual alternative?
2. ~~Should we add a `skip_params` attribute to avoid the `T: 'static`
trick?~~ ~~Decided to go with `custom_where()` as it's the simplest~~
Scratch that, went with a normal where clause
3. ~~`custom_where` bikeshedding?~~ No longer needed since we are using
a normal where clause
### TODO
- [x] Add compile-fail tests
---
## Changelog
- Fixed issue preventing recursive types from deriving `Reflect`
- Changed how where-clause bounds are generated by the `Reflect` derive
macro
- They are now only applied to the type parameters, not to all active
fields
- Added `#[reflect(where T: Trait, U::Assoc: Trait, ...)]` container
attribute
## Migration Guide
When deriving `Reflect`, generic type params that do not need the
automatic reflection bounds (such as `Reflect`) applied to them will
need to opt-out using a custom where clause like: `#[reflect(where T:
Trait, U::Assoc: Trait, ...)]`.
The attribute can define custom bounds only used by the reflection
impls. To simply opt-out all the type params, we can pass in an empty
where clause: `#[reflect(where)]`.
```rust
// BEFORE:
#[derive(Reflect)]
struct Foo<T>(#[reflect(ignore)] T);
// AFTER:
#[derive(Reflect)]
#[reflect(where)]
struct Foo<T>(#[reflect(ignore)] T);
```
---------
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
Fixes#11533
When `AssetPath`s are created from a string type, they are parsed into
an `AssetSource`, a `Path`, and a `Label`.
The current method of parsing has some unnecessary quirks:
- The presence of a `:` character is assumed to be the start of an asset
source indicator.
- This is not necessarily true. There are valid uses of a `:` character
in an asset path, for example an http source's port such as
`localhost:80`.
- If there are multiple instances of `://`, the last one is assumed to
be the asset source deliminator.
- This has some unexpected behavior. Even in a fully formed path, such
as `http://localhost:80`, the `:` between `localhost` and `80` is
assumed to be the start of an asset source, causing an error since it
does not form the full sequence `://`.
## Solution
Changes the `AssetPath`'s `parse_internal` method to be more permissive.
- Only the exact sequence `://` is taken to be the asset source
deliminator, and only the first one if there are multiple.
- As a consequence, it is no longer possible to detect a malformed asset
source deliminator, and so the corresponding error was removed.
# Objective
One of a few Bevy Asset improvements I would like to make: #11216.
Currently asset processing and asset saving are handled by the same
trait, `AssetSaver`. This makes it difficult to reuse saving
implementations and impossible to have a single "universal" saver for a
given asset type.
## Solution
This PR splits off the processing portion of `AssetSaver` into
`AssetTransformer`, which is responsible for transforming assets. This
change involves adding the `LoadTransformAndSave` processor, which
utilizes the new API. The `LoadAndSave` still exists since it remains
useful in situations where no "transformation" of the asset is done,
such as when compressing assets.
## Notes:
As an aside, Bikeshedding is welcome on the names. I'm not entirely
convinced by `AssetTransformer`, which was chosen mostly because
`AssetProcessor` is taken. Additionally, `LoadTransformSave` may be
sufficient instead of `LoadTransformAndSave`.
---
## Changelog
### Added
- `AssetTransformer` which is responsible for transforming Assets.
- `LoadTransformAndSave`, a `Process` implementation.
### Changed
- Changed `AssetSaver`'s responsibilities from processing and saving to
just saving.
- Updated `asset_processing` example to use new API.
- Old asset .meta files regenerated with new processor.
# Objective
- Fix documentation for `AssetReader::is_directory` (it is currently
exactly the same as docs for `read_directory`)
---------
Co-authored-by: Kanabenki <lucien.menassol@gmail.com>
# Objective
TypeUuid is deprecated, remove it.
## Migration Guide
Convert any uses of `#[derive(TypeUuid)]` with `#[derive(TypePath]` for
more complex uses see the relevant
[documentation](https://docs.rs/bevy/latest/bevy/prelude/trait.TypePath.html)
for more information.
---------
Co-authored-by: ebola <dev@axiomatic>
# Objective
- Fixes a hurdle encountered when debugging a panic caused by the file
watcher loading a `.gitignore` file, which was hard to debug because
there was no file name in the report, only `asset paths must have
extensions`
## Solution
- Panic with a formatted message that includes the asset path, e.g.
`missing expected extension for asset path .gitignore`
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Doonv <58695417+doonv@users.noreply.github.com>
# Objective
- `AssetPath` implements reflection, but is not registered as a type in
the plugin.
- Fixes#11481.
## Solution
- Register the `AssetPath` type when `AssetPlugin::build` is called.
---
## Changelog
- Registered `AssetPath` type for use in reflection.
# Objective
- Since #11218, example `asset_processing` fails:
```
thread 'main' panicked at crates/bevy_asset/src/io/source.rs:489:18:
Failed to create file watcher: Error { kind: PathNotFound, paths: ["examples/asset/processing/imported_assets/Default"] }
```
start from a fresh git clone or delete the folder before running to
reproduce, it is in gitignore and should not be present on a fresh run
a657478675/.gitignore (L18)
## Solution
- Auto create the `imported_assets` folder if it is configured
---------
Co-authored-by: Kyle <37520732+nvdaz@users.noreply.github.com>
# Objective
This adds events for assets that fail to load along with minor utility
methods to make them useful. This paves the way for users writing their
own error handling and retry systems, plus Bevy including robust retry
handling: #11349.
* Addresses #11288
* Needed for #11349
# Solution
```rust
/// An event emitted when a specific [`Asset`] fails to load.
#[derive(Event, Clone, Debug)]
pub struct AssetLoadFailedEvent<A: Asset> {
pub id: AssetId<A>,
/// The original handle returned when the asset load was requested.
pub handle: Option<Handle<A>>,
/// The asset path that was attempted.
pub path: AssetPath<'static>,
/// Why the asset failed to load.
pub error: AssetLoadError,
}
```
I started implementing `AssetEvent::Failed` like suggested in #11288,
but decided it was better as its own type because:
* I think it makes sense for `AssetEvent` to only refer to assets that
actually exist.
* In order to return `AssetLoadError` in the event (which is useful
information for error handlers that might attempt a retry) we would have
to remove `Copy` from `AssetEvent`.
* There are numerous places in the render app that match against
`AssetEvent`, and I don't think it's worth introducing extra noise about
assets that don't exist.
I also introduced `UntypedAssetLoadErrorEvent`, which is very useful in
places that need to support type flexibility, like an Asset-agnostic
retry plugin.
# Changelog
* **Added:** `AssetLoadFailedEvent<A>`
* **Added**: `UntypedAssetLoadFailedEvent`
* **Added:** `AssetReaderError::Http` for status code information on
HTTP errors. Before this, status codes were only available by parsing
the error message of generic `Io` errors.
* **Added:** `asset_server.get_path_id(path)`. This method simply gets
the asset id for the path. Without this, one was left using
`get_path_handle(path)`, which has the overhead of returning a strong
handle.
* **Fixed**: Made `AssetServer` loads return the same handle for assets
that already exist in a failed state. Now, when you attempt a `load`
that's in a `LoadState::Failed` state, it'll re-use the original asset
id. The advantage of this is that any dependent assets created using the
original handle will "unbreak" if a retry succeeds.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Tried using "embedded_watcher" feature and `embedded_asset!()` from
another crate. The assets embedded fine but were not "watched." The
problem appears to be that checking for the feature was done inside the
macro, so rather than checking if "embedded_watcher" was enabled for
bevy, it would check if it was enabled for the current crate.
## Solution
I extracted the checks for the "embedded_watcher" feature into its own
function called `watched_path()`. No external changes.
### Alternative Solution
An alternative fix would be to not do any feature checking in
`embedded_asset!()` or an extracted function and always send the
full_path to `insert_asset()` where it's promptly dropped when the
feature isn't turned on. That would be simpler.
```
($app: ident, $source_path: expr, $path: expr) => {{
let mut embedded = $app
.world
.resource_mut::<$crate::io::embedded::EmbeddedAssetRegistry>();
let path = $crate::embedded_path!($source_path, $path);
//#[cfg(feature = "embedded_watcher")]
let full_path = std::path::Path::new(file!()).parent().unwrap().join($path);
//#[cfg(not(feature = "embedded_watcher"))]
//let full_path = std::path::PathBuf::new();
embedded.insert_asset(full_path, &path, include_bytes!($path));
}};
```
## Changelog
> Fix embedded_watcher feature to work with external crates
# Objective
When you have no idea what to put after `#` when loading an asset, error
message may help.
## Solution
Add all labels to the error message.
## Test plan
Modified `anti_alias` example to put incorrect label, the error is:
```
2024-01-08T07:41:25.462287Z ERROR bevy_asset::server: The file at 'models/FlightHelmet/FlightHelmet.gltf' does not contain the labeled asset 'Rrrr'; it contains the following 25 assets: 'Material0', 'Material1', 'Material2', 'Material3', 'Material4', 'Material5', 'Mesh0', 'Mesh0/Primitive0', 'Mesh1', 'Mesh1/Primitive0', 'Mesh2', 'Mesh2/Primitive0', 'Mesh3', 'Mesh3/Primitive0', 'Mesh4', 'Mesh4/Primitive0', 'Mesh5', 'Mesh5/Primitive0', 'Node0', 'Node1', 'Node2', 'Node3', 'Node4', 'Node5', 'Scene0'
```
# Motivation
When spawning entities into a scene, it is very common to create assets
like meshes and materials and to add them via asset handles. A common
setup might look like this:
```rust
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
commands.spawn(PbrBundle {
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(StandardMaterial::from(Color::RED)),
..default()
});
}
```
Let's take a closer look at the part that adds the assets using `add`.
```rust
mesh: meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
material: materials.add(StandardMaterial::from(Color::RED)),
```
Here, "mesh" and "material" are both repeated three times. It's very
explicit, but I find it to be a bit verbose. In addition to being more
code to read and write, the extra characters can sometimes also lead to
the code being formatted to span multiple lines even though the core
task, adding e.g. a primitive mesh, is extremely simple.
A way to address this is by using `.into()`:
```rust
mesh: meshes.add(shape::Cube { size: 1.0 }.into()),
material: materials.add(Color::RED.into()),
```
This is fine, but from the names and the type of `meshes`, we already
know what the type should be. It's very clear that `Cube` should be
turned into a `Mesh` because of the context it's used in. `.into()` is
just seven characters, but it's so common that it quickly adds up and
gets annoying.
It would be nice if you could skip all of the conversion and let Bevy
handle it for you:
```rust
mesh: meshes.add(shape::Cube { size: 1.0 }),
material: materials.add(Color::RED),
```
# Objective
Make adding assets more ergonomic by making `Assets::add` take an `impl
Into<A>` instead of `A`.
## Solution
`Assets::add` now takes an `impl Into<A>` instead of `A`, so e.g. this
works:
```rust
commands.spawn(PbrBundle {
mesh: meshes.add(shape::Cube { size: 1.0 }),
material: materials.add(Color::RED),
..default()
});
```
I also changed all examples to use this API, which increases consistency
as well because `Mesh::from` and `into` were being used arbitrarily even
in the same file. This also gets rid of some lines of code because
formatting is nicer.
---
## Changelog
- `Assets::add` now takes an `impl Into<A>` instead of `A`
- Examples don't use `T::from(K)` or `K.into()` when adding assets
## Migration Guide
Some `into` calls that worked previously might now be broken because of
the new trait bounds. You need to either remove `into` or perform the
conversion explicitly with `from`:
```rust
// Doesn't compile
let mesh_handle = meshes.add(shape::Cube { size: 1.0 }.into()),
// These compile
let mesh_handle = meshes.add(shape::Cube { size: 1.0 }),
let mesh_handle = meshes.add(Mesh::from(shape::Cube { size: 1.0 })),
```
## Concerns
I believe the primary concerns might be:
1. Is this too implicit?
2. Does this increase codegen bloat?
Previously, the two APIs were using `into` or `from`, and now it's
"nothing" or `from`. You could argue that `into` is slightly more
explicit than "nothing" in cases like the earlier examples where a
`Color` gets converted to e.g. a `StandardMaterial`, but I personally
don't think `into` adds much value even in this case, and you could
still see the actual type from the asset type.
As for codegen bloat, I doubt it adds that much, but I'm not very
familiar with the details of codegen. I personally value the user-facing
code reduction and ergonomics improvements that these changes would
provide, but it might be worth checking the other effects in more
detail.
Another slight concern is migration pain; apps might have a ton of
`into` calls that would need to be removed, and it did take me a while
to do so for Bevy itself (maybe around 20-40 minutes). However, I think
the fact that there *are* so many `into` calls just highlights that the
API could be made nicer, and I'd gladly migrate my own projects for it.
# Objective
- No point in keeping Meshes/Images in RAM once they're going to be sent
to the GPU, and kept in VRAM. This saves a _significant_ amount of
memory (several GBs) on scenes like bistro.
- References
- https://github.com/bevyengine/bevy/pull/1782
- https://github.com/bevyengine/bevy/pull/8624
## Solution
- Augment RenderAsset with the capability to unload the underlying asset
after extracting to the render world.
- Mesh/Image now have a cpu_persistent_access field. If this field is
RenderAssetPersistencePolicy::Unload, the asset will be unloaded from
Assets<T>.
- A new AssetEvent is sent upon dropping the last strong handle for the
asset, which signals to the RenderAsset to remove the GPU version of the
asset.
---
## Changelog
- Added `AssetEvent::NoLongerUsed` and
`AssetEvent::is_no_longer_used()`. This event is sent when the last
strong handle of an asset is dropped.
- Rewrote the API for `RenderAsset` to allow for unloading the asset
data from the CPU.
- Added `RenderAssetPersistencePolicy`.
- Added `Mesh::cpu_persistent_access` for memory savings when the asset
is not needed except for on the GPU.
- Added `Image::cpu_persistent_access` for memory savings when the asset
is not needed except for on the GPU.
- Added `ImageLoaderSettings::cpu_persistent_access`.
- Added `ExrTextureLoaderSettings`.
- Added `HdrTextureLoaderSettings`.
## Migration Guide
- Asset loaders (GLTF, etc) now load meshes and textures without
`cpu_persistent_access`. These assets will be removed from
`Assets<Mesh>` and `Assets<Image>` once `RenderAssets<Mesh>` and
`RenderAssets<Image>` contain the GPU versions of these assets, in order
to reduce memory usage. If you require access to the asset data from the
CPU in future frames after the GLTF asset has been loaded, modify all
dependent `Mesh` and `Image` assets and set `cpu_persistent_access` to
`RenderAssetPersistencePolicy::Keep`.
- `Mesh` now requires a new `cpu_persistent_access` field. Set it to
`RenderAssetPersistencePolicy::Keep` to mimic the previous behavior.
- `Image` now requires a new `cpu_persistent_access` field. Set it to
`RenderAssetPersistencePolicy::Keep` to mimic the previous behavior.
- `MorphTargetImage::new()` now requires a new `cpu_persistent_access`
parameter. Set it to `RenderAssetPersistencePolicy::Keep` to mimic the
previous behavior.
- `DynamicTextureAtlasBuilder::add_texture()` now requires that the
`TextureAtlas` you pass has an `Image` with `cpu_persistent_access:
RenderAssetPersistencePolicy::Keep`. Ensure you construct the image
properly for the texture atlas.
- The `RenderAsset` trait has significantly changed, and requires
adapting your existing implementations.
- The trait now requires `Clone`.
- The `ExtractedAsset` associated type has been removed (the type itself
is now extracted).
- The signature of `prepare_asset()` is slightly different
- A new `persistence_policy()` method is now required (return
RenderAssetPersistencePolicy::Unload to match the previous behavior).
- Match on the new `NoLongerUsed` variant for exhaustive matches of
`AssetEvent`.
# Objective
There are a lot of doctests that are `ignore`d for no documented reason.
And that should be fixed.
## Solution
I searched the bevy repo with the regex ` ```[a-z,]*ignore ` in order to
find all `ignore`d doctests. For each one of the `ignore`d doctests, I
did the following steps:
1. Attempt to remove the `ignored` attribute while still passing the
test. I did this by adding hidden dummy structs and imports.
2. If step 1 doesn't work, attempt to replace the `ignored` attribute
with the `no_run` attribute while still passing the test.
3. If step 2 doesn't work, keep the `ignored` attribute but add
documentation for why the `ignored` attribute was added.
---------
Co-authored-by: François <mockersf@gmail.com>
# Objective
- Make the implementation order consistent between all sources to fit
the order in the trait.
## Solution
- Change the implementation order.
# Objective
- Update winit dependency to 0.29
## Changelog
### KeyCode changes
- Removed `ScanCode`, as it was [replaced by
KeyCode](https://github.com/rust-windowing/winit/blob/master/CHANGELOG.md#0292).
- `ReceivedCharacter.char` is now a `SmolStr`, [relevant
doc](https://docs.rs/winit/latest/winit/event/struct.KeyEvent.html#structfield.text).
- Changed most `KeyCode` values, and added more.
KeyCode has changed meaning. With this PR, it refers to physical
position on keyboard rather than the printed letter on keyboard keys.
In practice this means:
- On QWERTY keyboard layouts, nothing changes
- On any other keyboard layout, `KeyCode` no longer reflects the label
on key.
- This is "good". In bevy 0.12, when you used WASD for movement, users
with non-QWERTY keyboards couldn't play your game! This was especially
bad for non-latin keyboards. Now, WASD represents the physical keys. A
French player will press the ZQSD keys, which are near each other,
Kyrgyz players will use "Цфыв".
- This is "bad" as well. You can't know in advance what the label of the
key for input is. Your UI says "press WASD to move", even if in reality,
they should be pressing "ZQSD" or "Цфыв". You also no longer can use
`KeyCode` for text inputs. In any case, it was a pretty bad API for text
input. You should use `ReceivedCharacter` now instead.
### Other changes
- Use `web-time` rather than `instant` crate.
(https://github.com/rust-windowing/winit/pull/2836)
- winit did split `run_return` in `run_onDemand` and `pump_events`, I
did the same change in bevy_winit and used `pump_events`.
- Removed `return_from_run` from `WinitSettings` as `winit::run` now
returns on supported platforms.
- I left the example "return_after_run" as I think it's still useful.
- This winit change is done partly to allow to create a new window after
quitting all windows: https://github.com/emilk/egui/issues/1918 ; this
PR doesn't address.
- added `width` and `height` properties in the `canvas` from wasm
example
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1420567168)
## Known regressions (important follow ups?)
- Provide an API for reacting when a specific key from current layout
was released.
- possible solutions: use winit::Key from winit::KeyEvent ; mapping
between KeyCode and Key ; or .
- We don't receive characters through alt+numpad (e.g. alt + 151 = "ù")
anymore ; reproduced on winit example "ime". maybe related to
https://github.com/rust-windowing/winit/issues/2945
- (windows) Window content doesn't refresh at all when resizing. By
reading https://github.com/rust-windowing/winit/issues/2900 ; I suspect
we should just fire a `window.request_redraw();` from `AboutToWait`, and
handle actual redrawing within `RedrawRequested`. I'm not sure how to
move all that code so I'd appreciate it to be a follow up.
- (windows) unreleased winit fix for using set_control_flow in
AboutToWait https://github.com/rust-windowing/winit/issues/3215 ; ⚠️ I'm
not sure what the implications are, but that feels bad 🤔
## Follow up
I'd like to avoid bloating this PR, here are a few follow up tasks
worthy of a separate PR, or new issue to track them once this PR is
closed, as they would either complicate reviews, or at risk of being
controversial:
- remove CanvasParentResizePlugin
(https://github.com/bevyengine/bevy/pull/10702#discussion_r1417068856)
- avoid mentionning explicitly winit in docs from bevy_window ?
- NamedKey integration on bevy_input:
https://github.com/rust-windowing/winit/pull/3143 introduced a new
NamedKey variant. I implemented it only on the converters but we'd
benefit making the same changes to bevy_input.
- Add more info in KeyboardInput
https://github.com/bevyengine/bevy/pull/10702#pullrequestreview-1748336313
- https://github.com/bevyengine/bevy/pull/9905 added a workaround on a
bug allegedly fixed by winit 0.29. We should check if it's still
necessary.
- update to raw_window_handle 0.6
- blocked by wgpu
- Rename `KeyCode` to `PhysicalKeyCode`
https://github.com/bevyengine/bevy/pull/10702#discussion_r1404595015
- remove `instant` dependency, [replaced
by](https://github.com/rust-windowing/winit/pull/2836) `web_time`), we'd
need to update to :
- fastrand >= 2.0
- [`async-executor`](https://github.com/smol-rs/async-executor) >= 1.7
- [`futures-lite`](https://github.com/smol-rs/futures-lite) >= 2.0
- Verify license, see
[discussion](https://github.com/bevyengine/bevy/pull/8745#discussion_r1402439800)
- we might be missing a short notice or description of changes made
- Consider using https://github.com/rust-windowing/cursor-icon directly
rather than vendoring it in bevy.
- investigate [this
unwrap](https://github.com/bevyengine/bevy/pull/8745#discussion_r1387044986)
(`winit_window.canvas().unwrap();`)
- Use more good things about winit's update
- https://github.com/bevyengine/bevy/pull/10689#issuecomment-1823560428
## Migration Guide
This PR should have one.
# Objective
- Reduce nesting in `process_handle_drop_internal()`.
- Related to #10896.
## Solution
- Use early returns when possible.
- Reduced from 9 levels of indents to 4.
# Objective
Fixes#10444
Currently manually removing an asset prevents it from being reloaded
while there are still active handles. Doing so will result in a panic,
because the storage entry has been marked as "empty / None" but the ID
is still assumed to be active by the asset server.
Patterns like `images.remove() -> asset_server.reload()` and
`images.remove() -> images.insert()` would fail if the handle was still
alive.
## Solution
Most of the groundwork for this was already laid in Bevy Asset V2. This
is largely just a matter of splitting out `remove` into two separate
operations:
* `remove_dropped`: remove the stored asset, invalidate the internal
Assets entry (preventing future insertions with the old id), and recycle
the id
* `remove_still_alive`: remove the stored asset, but leave the entry
otherwise untouched (and dont recycle the id).
`remove_still_alive` and `insert` can be called any number of times (in
any order) for an id until `remove_dropped` has been called, which will
invalidate the id.
From a user-facing perspective, there are no API changes and this is non
breaking. The public `Assets::remove` will internally call
`remove_still_alive`. `remove_dropped` can only be called by the
internal "handle management" system.
---
## Changelog
- Fix a bug preventing `Assets::remove` from blocking future inserts for
a specific `AssetIndex`.
# Objective
Fixes#10401
## Solution
* Allow sources to register specific processed/unprocessed watch
warnings.
* Specify per-platform watch warnings. This removes the need to cover
all platform cases in one warning message.
* Only register watch warnings for the _processed_ embedded source, as
warning about watching unprocessed embedded isn't helpful.
---
## Changelog
- Asset sources can now register specific watch warnings.
# Objective
- Shorten paths by removing unnecessary prefixes
## Solution
- Remove the prefixes from many paths which do not need them. Finding
the paths was done automatically using built-in refactoring tools in
Jetbrains RustRover.
# Objective
Related to #10612.
Enable the
[`clippy::manual_let_else`](https://rust-lang.github.io/rust-clippy/master/#manual_let_else)
lint as a warning. The `let else` form seems more idiomatic to me than a
`match`/`if else` that either match a pattern or diverge, and from the
clippy doc, the lint doesn't seem to have any possible false positive.
## Solution
Add the lint as warning in `Cargo.toml`, refactor places where the lint
triggers.
# Objective
Fixes#10688
There were a number of issues at play:
1. The GLTF loader was not registering Scene dependencies properly. They
were being registered at the root instead of on the scene assets. This
made `LoadedWithDependencies` fire immediately on load.
2. Recursive labeled assets _inside_ of labeled assets were not being
loaded. This only became relevant for scenes after fixing (1) because we
now add labeled assets to the nested scene `LoadContext` instead of the
root load context. I'm surprised nobody has hit this yet. I'm glad I
caught it before somebody hit it.
3. Accessing "loaded with dependencies" state on the Asset Server is
boilerplatey + error prone (because you need to manually query two
states).
## Solution
1. In GltfLoader, use a nested LoadContext for scenes and load
dependencies through that context.
2. In the `AssetServer`, load labeled assets recursively.
3. Added a simple `asset_server.is_loaded_with_dependencies(id)`
I also added some docs to `LoadContext` to help prevent this problem in
the future.
---
## Changelog
- Added `AssetServer::is_loaded_with_dependencies`
- Fixed GLTF Scene dependencies
- Fixed nested labeled assets not being loaded
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Fixes#10157
## Solution
Add `AssetMetaCheck` resource which can configure when/if asset meta
files will be read:
```rust
app
// Never attempts to look up meta files. The default meta configuration will be used for each asset.
.insert_resource(AssetMetaCheck::Never)
.add_plugins(DefaultPlugins)
```
This serves as a band-aid fix for the issue with wasm's
`HttpWasmAssetReader` creating a bunch of requests for non-existent
meta, which can slow down asset loading (by waiting for the 404
response) and creates a bunch of noise in the logs. This also provides a
band-aid fix for the more serious issue of itch.io deployments returning
403 responses, which results in full failure of asset loads.
If users don't want to include meta files for all deployed assets for
web builds, and they aren't using meta files at all, they should set
this to `AssetMetaCheck::Never`.
If users do want to include meta files for specific assets, they can use
`AssetMetaCheck::Paths`, which will only look up meta for those paths.
Currently, this defaults to `AssetMetaCheck::Always`, which makes this
fully non-breaking for the `0.12.1` release. _**However it _is_ worth
discussing making this `AssetMetaCheck::Never` by default**_, given that
I doubt most people are using meta files without the Asset Processor
enabled. This would be a breaking change, but it would make WASM / Itch
deployments work by default, which is a pretty big win imo. The downside
is that people using meta files _without_ processing would need to
manually enable `AssetMetaCheck::Always`, which is also suboptimal.
When in `AssetMetaCheck::Processed`, the meta check resource is ignored,
as processing requires asset meta files to function.
In general, I don't love adding this knob as things should ideally "just
work" in all cases. But this is the reality of the current situation.
---
## Changelog
- Added `AssetMetaCheck` resource, which can configure when/if asset
meta files will be read
# Objective
Updates [`futures-lite`](https://github.com/smol-rs/futures-lite) in
bevy_tasks to the next major version (1 -> 2).
Also removes the duplication of `futures-lite`, as `async-fs` requires v
2, so there are currently 2 copies of futures-lite in the dependency
tree.
Futures-lite has received [a number of
updates](https://github.com/smol-rs/futures-lite/blob/master/CHANGELOG.md)
since bevy's current version `1.4`.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Mike <mike.hsu@gmail.com>
# Objective
- Fixes#10695
## Solution
Fixed obvious blunder in `PartialEq` implementation for
`UntypedAssetId`'s where the `TypeId` was not included in the
comparison. This was not picked up in the unit tests I added because
they only tested over a single asset type.
# Objective
- Fixes#10629
- `UntypedAssetId` and `AssetId` (along with `UntypedHandle` and
`Handle`) do not hash to the same values when pointing to the same
`Asset`. Additionally, comparison and conversion between these types
does not follow idiomatic Rust standards.
## Solution
- Added new unit tests to validate/document expected behaviour
- Added trait implementations to make working with Un/Typed values more
ergonomic
- Ensured hashing and comparison between Un/Typed values is consistent
- Removed `From` trait implementations that panic, and replaced them
with `TryFrom`
---
## Changelog
- Ensured `Handle::<A>::hash` and `UntypedHandle::hash` will produce the
same value for the same `Asset`
- Added non-panicing `Handle::<A>::try_typed`
- Added `PartialOrd` to `UntypedHandle` to match `Handle<A>` (this will
return `None` for `UntypedHandles` for differing `Asset` types)
- Added `TryFrom<UntypedHandle>` for `Handle<A>`
- Added `From<Handle<A>>` for `UntypedHandle`
- Removed panicing `From<Untyped...>` implementations. These are
currently unused within the Bevy codebase, and shouldn't be used
externally, hence removal.
- Added cross-implementations of `PartialEq` and `PartialOrd` for
`UntypedHandle` and `Handle<A>` allowing direct comparison when
`TypeId`'s match.
- Near-identical changes to `AssetId` and `UntypedAssetId`
## Migration Guide
If you relied on any of the panicing `From<Untyped...>` implementations,
simply call the existing `typed` methods instead. Alternatively, use the
new `TryFrom` implementation instead to directly expose possible
mistakes.
## Notes
I've made these changes since `Handle` is such a fundamental type to the
entire `Asset` ecosystem within Bevy, and yet it had pretty unclear
behaviour with no direct testing. The fact that hashing untyped vs typed
versions of the same handle would produce different values is something
I expect to cause a very subtle bug for someone else one day.
I haven't included it in this PR to avoid any controversy, but I also
believe the `typed_unchecked` methods should be removed from these
types, or marked as `unsafe`. The `texture_atlas` example currently uses
it, and I believe it is a bad choice. The performance gained by not
type-checking before conversion would be entirely dwarfed by the act of
actually loading an asset and creating its handle anyway. If an end user
is in a tight loop repeatedly calling `typed_unchecked` on an
`UntypedHandle` for the entire runtime of their application, I think the
small performance drop caused by that safety check is ~~a form of cosmic
justice~~ reasonable.
# Objective
Fix the `bevy_asset/file_watcher` feature in practice depending on
multithreading, while not informing the user of it.
**As I understand it** (I didn't check it), the file watcher feature
depends on spawning a concurrent thread to receive file update events
from the `notify-debouncer-full` crate. But if multithreading is
disabled, that thread will never have time to read the events and
consume them.
- Fixes#10573
## Solution
Add a `compile_error!` causing compilation failure if `file_watcher` is
enabled while `multi-threaded` is disabled.
This is considered better than adding a dependency on `multi-threaded`
on the `file_watcher`, as (according to @mockersf) toggling on/off
`multi-threaded` has a non-zero chance of changing behavior. And we
shouldn't implicitly change behavior. A compilation failure prevents
compilation of code that is invalid, while informing the user of the
steps needed to fix it.