# Objective
I noticed while working on #5366 that the documentation for label types wasn't working correctly. Having experimented with this for a few weeks, I believe that generating docs in macros is more effort than it's worth.
## Solution
Add more boilerplate, copy-paste and edit the docs across types. This also lets us add custom doctests for specific types. Also, we don't need `concat_idents` as a dependency anymore.
# Objective
- Closes#4954
- Reduce the complexity of the `{System, App, *}Label` APIs.
## Solution
For the sake of brevity I will only refer to `SystemLabel`, but everything applies to all of the other label types as well.
- Add `SystemLabelId`, a lightweight, `copy` struct.
- Convert custom types into `SystemLabelId` using the trait `SystemLabel`.
## Changelog
- String literals implement `SystemLabel` for now, but this should be changed with #4409 .
## Migration Guide
- Any previous use of `Box<dyn SystemLabel>` should be replaced with `SystemLabelId`.
- `AsSystemLabel` trait has been modified.
- No more output generics.
- Method `as_system_label` now returns `SystemLabelId`, removing an unnecessary level of indirection.
- If you *need* a label that is determined at runtime, you can use `Box::leak`. Not recommended.
## Questions for later
* Should we generate a `Debug` impl along with `#[derive(*Label)]`?
* Should we rename `as_str()`?
* Should we remove the extra derives (such as `Hash`) from builtin `*Label` types?
* Should we automatically derive types like `Clone, Copy, PartialEq, Eq`?
* More-ergonomic comparisons between `Label` and `LabelId`.
* Move `Dyn{Eq, Hash,Clone}` somewhere else.
* Some API to make interning dynamic labels easier.
* Optimize string representation
* Empty string for unit structs -- no debug info but faster comparisons
* Don't show enum types -- same tradeoffs as asbove.
# Objective
- Slight documentation tweak to make it more clear that `FloatOrd` also implements `Hash` and `Eq`, not just `Ord`.
- I know that it does show that Hash is implemented in the docs, but I had missed it after reading the description and assuming it didn't do it, so hopefully this helps other people who might miss it like I did. :)
## Solution
- Just mention in the Hash and Eq implementation in the docstring.
# Objective
`SAFETY` comments are meant to be placed before `unsafe` blocks and should contain the reasoning of why in this case the usage of unsafe is okay. This is useful when reading the code because it makes it clear which assumptions are required for safety, and makes it easier to spot possible unsoundness holes. It also forces the code writer to think of something to write and maybe look at the safety contracts of any called unsafe methods again to double-check their correct usage.
There's a clippy lint called `undocumented_unsafe_blocks` which warns when using a block without such a comment.
## Solution
- since clippy expects `SAFETY` instead of `SAFE`, rename those
- add `SAFETY` comments in more places
- for the last remaining 3 places, add an `#[allow()]` and `// TODO` since I wasn't comfortable enough with the code to justify their safety
- add ` #![warn(clippy::undocumented_unsafe_blocks)]` to `bevy_ecs`
### Note for reviewers
The first commit only renames `SAFETY` to `SAFE` so it doesn't need a thorough review.
cb042a416e..55cef2d6fa is the diff for all other changes.
### Safety comments where I'm not too familiar with the code
774012ece5/crates/bevy_ecs/src/entity/mod.rs (L540-L546)774012ece5/crates/bevy_ecs/src/world/entity_ref.rs (L249-L252)
### Locations left undocumented with a `TODO` comment
5dde944a30/crates/bevy_ecs/src/schedule/executor_parallel.rs (L196-L199)5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L287-L289)5dde944a30/crates/bevy_ecs/src/world/entity_ref.rs (L413-L415)
Co-authored-by: Jakob Hellermann <hellermann@sipgate.de>
# Summary
This method strips a long type name like `bevy::render:📷:PerspectiveCameraBundle` down into the bare type name (`PerspectiveCameraBundle`). This is generally useful utility method, needed by #4299 and #5121.
As a result:
- This method was moved to `bevy_utils` for easier reuse.
- The legibility and robustness of this method has been significantly improved.
- Harder test cases have been added.
This change was split out of #4299 to unblock it and make merging / reviewing the rest of those changes easier.
## Changelog
- added `bevy_utils::get_short_name`, which strips the path from a type name for convenient display.
- removed the `TypeRegistry::get_short_name` method. Use the function in `bevy_utils` instead.
# Objective
We have some macros that are public but only used internally for now. They fail on user's code due to the use of crate names like `bevy_utils`, while the user only has `bevy::utils`. There are two affected macros.
- `bevy_utils::define_label`: it may be useful in user's code for defining custom kinds of label traits (this is why I made this PR).
- `bevy_asset::load_internal_asset`: not useful currently due to limitations of the debug asset server, but this may change in the future.
## Solution
We can make them work by using `$crate` instead of names of their own crates, which can refer to the macro's defining crate regardless of the user's setup. Even though our objective is rather low-priority here, the solution adds no maintenance cost so it is still worthwhile.
# Objective
Reduce from scratch build time.
## Solution
Reduce the size of the critical path by removing dependencies between crates where not necessary. For `cargo check --no-default-features` this reduced build time from ~51s to ~45s. For some commits I am not completely sure if the tradeoff between build time reduction and convenience caused by the commit is acceptable. If not, I can drop them.
# Objective
Reduce the catch-all grab-bag of functionality in bevy_core by moving FloatOrd to bevy_utils.
A step in addressing #2931 and splitting bevy_core into more specific locations.
## Solution
Move FloatOrd into bevy_utils. Fix the compile errors.
As a result, bevy_core_pipeline, bevy_pbr, bevy_sprite, bevy_text, and bevy_ui no longer depend on bevy_core (they were only using it for `FloatOrd` previously).
related: https://github.com/bevyengine/bevy/pull/3289
In addition to validating shaders early when debug assertions are enabled, use the new [error scopes](https://gpuweb.github.io/gpuweb/#error-scopes) API when creating a shader module.
I chose to keep the early validation (and thereby parsing twice) when debug assertions are enabled in, because it lets as handle errors ourselves and display them with pretty colors, while the error scopes API just gives us a string we can display.
This change pulls in `futures-util` as a new dependency for `future.now_or_never()`. I can inline that part of futures-lite into `bevy_render` to keep the compilation time lower if that's preferred.
Adds a `default()` shorthand for `Default::default()` ... because life is too short to constantly type `Default::default()`.
```rust
use bevy::prelude::*;
#[derive(Default)]
struct Foo {
bar: usize,
baz: usize,
}
// Normally you would do this:
let foo = Foo {
bar: 10,
..Default::default()
};
// But now you can do this:
let foo = Foo {
bar: 10,
..default()
};
```
The examples have been adapted to use `..default()`. I've left internal crates as-is for now because they don't pull in the bevy prelude, and the ergonomics of each case should be considered individually.
For some keys, it is too expensive to hash them on every lookup. Historically in Bevy, we have regrettably done the "wrong" thing in these cases (pre-computing hashes, then re-hashing them) because Rust's built in hashed collections don't give us the tools we need to do otherwise. Doing this is "wrong" because two different values can result in the same hash. Hashed collections generally get around this by falling back to equality checks on hash collisions. You can't do that if the key _is_ the hash. Additionally, re-hashing a hash increase the odds of collision!
#3959 needs pre-hashing to be viable, so I decided to finally properly solve the problem. The solution involves two different changes:
1. A new generalized "pre-hashing" solution in bevy_utils: `Hashed<T>` types, which store a value alongside a pre-computed hash. And `PreHashMap<K, V>` (which uses `Hashed<T>` internally) . `PreHashMap` is just an alias for a normal HashMap that uses `Hashed<T>` as the key and a new `PassHash` implementation as the Hasher.
2. Replacing the `std::collections` re-exports in `bevy_utils` with equivalent `hashbrown` impls. Avoiding re-hashes requires the `raw_entry_mut` api, which isn't stabilized yet (and may never be ... `entry_ref` has favor now, but also isn't available yet). If std's HashMap ever provides the tools we need, we can move back to that. The latest version of `hashbrown` adds support for the `entity_ref` api, so we can move to that in preparation for an std migration, if thats the direction they seem to be going in. Note that adding hashbrown doesn't increase our dependency count because it was already in our tree.
In addition to providing these core tools, I also ported the "table identity hashing" in `bevy_ecs` to `raw_entry_mut`, which was a particularly egregious case.
The biggest outstanding case is `AssetPathId`, which stores a pre-hash. We need AssetPathId to be cheaply clone-able (and ideally Copy), but `Hashed<AssetPath>` requires ownership of the AssetPath, which makes cloning ids way more expensive. We could consider doing `Hashed<Arc<AssetPath>>`, but cloning an arc is still a non-trivial expensive that needs to be considered. I would like to handle this in a separate PR. And given that we will be re-evaluating the Bevy Assets implementation in the very near future, I'd prefer to hold off until after that conversation is concluded.
#3457 adds the `doc_markdown` clippy lint, which checks doc comments to make sure code identifiers are escaped with backticks. This causes a lot of lint errors, so this is one of a number of PR's that will fix those lint errors one crate at a time.
This PR fixes lints in the `bevy_utils` crate.
# Objective
Fixes#2823.
## Solution
This PR adds notes to the `HashMap` and `HashSet` docs explaining why `HashMap::new()` (resp. `HashSet::new()`) is not available, and guiding the user toward using the `Default` implementation for an empty collection.
This matches `ahash::RandomState`, which provides both `Debug` and `Clone`.
Notably, implementing `Clone` allows the `StableHashMap`/`Set` to also implement `Clone`.
# Objective
- Allow `bevy_utils::StableHashMap` to be cloned.
## Solution
- Derive `Clone` for `bevy_utils::FixedState`.
- Also derive `Debug`, since we're touching it anyway, and this aligns `FixedState` with `ahash::RandomState`.
This is a rather simple but wide change, and it involves adding a new `bevy_app_macros` crate. Let me know if there is a better way to do any of this!
---
# Objective
- Allow adding and accessing sub-apps by using a label instead of an index
## Solution
- Migrate the bevy label implementation and derive code to the `bevy_utils` and `bevy_macro_utils` crates and then add a new `SubAppLabel` trait to the `bevy_app` crate that is used when adding or getting a sub-app from an app.
# Objective
Re-introduce `AHashExt` and respective `with_capacity()` implementations to give a more ergonomic way to set a `HashMap` / `HashSet` capacity.
As a note, this has also been discussed and agreed on issue #2115, which this PR addresses (leaving `new()` out of the `AHashExt` trait).
Fixes#2115.
## Solution
PR #1235 had removed the `AHashExt` trait and respective `with_capacity()`s implementations, leaving only the less ergonomic `HashMap::with_capacity_and_hasher(size, Default::default())` option available.
This re-introduces `AHashExt` and respective `with_capacity()` implementations to give a more ergonomic way to set a `HashMap` / `HashSet` capacity.
There are cases where we want an enum variant name. Right now the only way to do that with rust's std is to derive Debug, but this will also print out the variant's fields. This creates the unfortunate situation where we need to manually write out each variant's string name (ex: in #1963), which is both boilerplate-ey and error-prone. Crates such as `strum` exist for this reason, but it includes a lot of code and complexity that we don't need.
This adds a dead-simple `EnumVariantMeta` derive that exposes `enum_variant_index` and `enum_variant_name` functions. This allows us to make cases like #1963 much cleaner (see the second commit). We might also be able to reuse this logic for `bevy_reflect` enum derives.
* Remove AHashExt
There is little benefit of Hash*::new() over Hash*::default(), but it
does require more code that needs to be duplicated for every Hash* in
bevy_utils. It may also slightly increase compile times.
* Add StableHash* to bevy_utils
* Use StableHashMap instead of HashMap + BTreeSet for diagnostics
This is a significant reduction in the release mode compile times of
bevy_diagnostics
```
Benchmark #1: touch crates/bevy_diagnostic/src/lib.rs && cargo build --release -p bevy_diagnostic -j1
Time (mean ± σ): 3.645 s ± 0.009 s [User: 3.551 s, System: 0.094 s]
Range (min … max): 3.632 s … 3.658 s 20 runs
```
```
Benchmark #1: touch crates/bevy_diagnostic/src/lib.rs && cargo build --release -p bevy_diagnostic -j1
Time (mean ± σ): 2.938 s ± 0.012 s [User: 2.850 s, System: 0.090 s]
Range (min … max): 2.919 s … 2.969 s 20 runs
```
