Simplify bevy_utils Features (#19090)

bushrat011899 · web-flow · commit 3d3746e5d021 · 2025-05-24T01:46:11.000Z
# Objective

Now that `bevy_platform::cfg` is merged, we can start tidying up
features. This PR starts with `bevy_utils`.

## Solution

- Removed `serde` and `critical-section` features (they were just
re-exports of `bevy_platform` anyway)
- Removed `std`, `alloc` features, relying on `bevy_platform::cfg` to
check for availability.
- Added `parallel` feature to provide access to the `Parallel` type.
- Moved the `HashMap` type aliases into `map.rs` for better
organisation.

## Testing

- CI
diff --git a/crates/bevy_app/Cargo.toml b/crates/bevy_app/Cargo.toml
@@ -47,7 +47,6 @@ std = [
   "bevy_ecs/std",
   "dep:ctrlc",
   "downcast-rs/std",
-  "bevy_utils/std",
   "bevy_tasks/std",
   "bevy_platform/std",
 ]
@@ -77,9 +76,7 @@ web = [
 bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
 bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, optional = true }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false, features = [
-  "alloc",
-] }
+bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
 bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
 bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false }
 
diff --git a/crates/bevy_diagnostic/Cargo.toml b/crates/bevy_diagnostic/Cargo.toml
@@ -18,7 +18,6 @@ serialize = [
   "dep:serde",
   "bevy_ecs/serialize",
   "bevy_time/serialize",
-  "bevy_utils/serde",
   "bevy_platform/serialize",
 ]
 
@@ -39,7 +38,6 @@ std = [
   "bevy_app/std",
   "bevy_platform/std",
   "bevy_time/std",
-  "bevy_utils/std",
   "bevy_tasks/std",
 ]
 
@@ -50,7 +48,6 @@ critical-section = [
   "bevy_app/critical-section",
   "bevy_platform/critical-section",
   "bevy_time/critical-section",
-  "bevy_utils/critical-section",
   "bevy_tasks/critical-section",
 ]
 
@@ -59,9 +56,7 @@ critical-section = [
 bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false }
 bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
 bevy_time = { path = "../bevy_time", version = "0.16.0-dev", default-features = false }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false, features = [
-  "alloc",
-] }
+bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
 bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
 bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
   "alloc",
diff --git a/crates/bevy_ecs/Cargo.toml b/crates/bevy_ecs/Cargo.toml
@@ -20,12 +20,7 @@ default = ["std", "bevy_reflect", "async_executor", "backtrace"]
 multi_threaded = ["bevy_tasks/multi_threaded", "dep:arrayvec"]
 
 ## Adds serialization support through `serde`.
-serialize = [
-  "dep:serde",
-  "bevy_utils/serde",
-  "bevy_platform/serialize",
-  "indexmap/serde",
-]
+serialize = ["dep:serde", "bevy_platform/serialize", "indexmap/serde"]
 
 ## Adds runtime reflection support using `bevy_reflect`.
 bevy_reflect = ["dep:bevy_reflect"]
@@ -67,7 +62,7 @@ async_executor = ["std", "bevy_tasks/async_executor"]
 std = [
   "bevy_reflect?/std",
   "bevy_tasks/std",
-  "bevy_utils/std",
+  "bevy_utils/parallel",
   "bitflags/std",
   "concurrent-queue/std",
   "disqualified/alloc",
@@ -94,9 +89,7 @@ bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
   "smallvec",
 ], default-features = false, optional = true }
 bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false, features = [
-  "alloc",
-] }
+bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
 bevy_ecs_macros = { path = "macros", version = "0.16.0-dev" }
 bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
   "alloc",
diff --git a/crates/bevy_image/Cargo.toml b/crates/bevy_image/Cargo.toml
@@ -32,7 +32,7 @@ qoi = ["image/qoi"]
 tga = ["image/tga"]
 tiff = ["image/tiff"]
 webp = ["image/webp"]
-serialize = ["bevy_reflect", "bevy_platform/serialize", "bevy_utils/serde"]
+serialize = ["bevy_reflect", "bevy_platform/serialize"]
 
 # For ktx2 supercompression
 zlib = ["flate2"]
diff --git a/crates/bevy_input/Cargo.toml b/crates/bevy_input/Cargo.toml
@@ -42,7 +42,6 @@ std = [
   "bevy_app/std",
   "bevy_ecs/std",
   "bevy_math/std",
-  "bevy_utils/std",
   "bevy_reflect/std",
   "bevy_platform/std",
 ]
diff --git a/crates/bevy_internal/Cargo.toml b/crates/bevy_internal/Cargo.toml
@@ -296,7 +296,6 @@ std = [
   "bevy_state?/std",
   "bevy_time/std",
   "bevy_transform/std",
-  "bevy_utils/std",
   "bevy_tasks/std",
   "bevy_window?/std",
 ]
@@ -314,7 +313,6 @@ critical-section = [
   "bevy_reflect/critical-section",
   "bevy_state?/critical-section",
   "bevy_time/critical-section",
-  "bevy_utils/critical-section",
   "bevy_tasks/critical-section",
 ]
 
@@ -377,9 +375,7 @@ bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev", default-f
   "bevy-support",
   "bevy_reflect",
 ] }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false, features = [
-  "alloc",
-] }
+bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
 bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
 
 # bevy (std required)
diff --git a/crates/bevy_reflect/Cargo.toml b/crates/bevy_reflect/Cargo.toml
@@ -54,7 +54,6 @@ wgpu-types = ["dep:wgpu-types"]
 ## on `no_std` targets, but provides access to certain additional features on
 ## supported platforms.
 std = [
-  "bevy_utils/std",
   "erased-serde/std",
   "downcast-rs/std",
   "serde/std",
@@ -67,10 +66,7 @@ std = [
 
 ## `critical-section` provides the building blocks for synchronization primitives
 ## on all platforms, including `no_std`.
-critical-section = [
-  "bevy_platform/critical-section",
-  "bevy_utils/critical-section",
-]
+critical-section = ["bevy_platform/critical-section"]
 
 ## Enables use of browser APIs.
 ## Note this is currently only applicable on `wasm32` architectures.
@@ -79,9 +75,7 @@ web = ["bevy_platform/web", "uuid?/js"]
 [dependencies]
 # bevy
 bevy_reflect_derive = { path = "derive", version = "0.16.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false, features = [
-  "alloc",
-] }
+bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
 bevy_ptr = { path = "../bevy_ptr", version = "0.16.0-dev" }
 bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
   "alloc",
diff --git a/crates/bevy_state/Cargo.toml b/crates/bevy_state/Cargo.toml
@@ -30,7 +30,6 @@ bevy_app = ["dep:bevy_app"]
 ## supported platforms.
 std = [
   "bevy_ecs/std",
-  "bevy_utils/std",
   "bevy_reflect?/std",
   "bevy_app?/std",
   "bevy_platform/std",
@@ -40,7 +39,6 @@ std = [
 ## on all platforms, including `no_std`.
 critical-section = [
   "bevy_ecs/critical-section",
-  "bevy_utils/critical-section",
   "bevy_app?/critical-section",
   "bevy_reflect?/critical-section",
   "bevy_platform/critical-section",
diff --git a/crates/bevy_transform/Cargo.toml b/crates/bevy_transform/Cargo.toml
@@ -74,7 +74,7 @@ std = [
   "bevy_math/std",
   "bevy_reflect?/std",
   "bevy_tasks/std",
-  "bevy_utils/std",
+  "bevy_utils/parallel",
   "serde?/std",
 ]
 
diff --git a/crates/bevy_utils/Cargo.toml b/crates/bevy_utils/Cargo.toml
@@ -9,26 +9,10 @@ license = "MIT OR Apache-2.0"
 keywords = ["bevy"]
 
 [features]
-default = ["std", "serde"]
+default = ["parallel"]
 
-# Functionality
-
-## Adds serialization support through `serde`.
-serde = ["bevy_platform/serialize"]
-
-# Platform Compatibility
-
-## Allows access to the `std` crate. Enabling this feature will prevent compilation
-## on `no_std` targets, but provides access to certain additional features on
-## supported platforms.
-std = ["alloc", "bevy_platform/std", "dep:thread_local"]
-
-## Allows access to the `alloc` crate.
-alloc = ["bevy_platform/alloc"]
-
-## `critical-section` provides the building blocks for synchronization primitives
-## on all platforms, including `no_std`.
-critical-section = ["bevy_platform/critical-section"]
+# Provides access to the `Parallel` type.
+parallel = ["bevy_platform/std", "dep:thread_local"]
 
 [dependencies]
 bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false }
diff --git a/crates/bevy_utils/src/lib.rs b/crates/bevy_utils/src/lib.rs
@@ -9,11 +9,35 @@
 //!
 //! [Bevy]: https://bevyengine.org/
 
-#[cfg(feature = "std")]
-extern crate std;
+/// Configuration information for this crate.
+pub mod cfg {
+    pub(crate) use bevy_platform::cfg::*;
 
-#[cfg(feature = "alloc")]
-extern crate alloc;
+    pub use bevy_platform::cfg::{alloc, std};
+
+    define_alias! {
+        #[cfg(feature = "parallel")] => {
+            /// Indicates the `Parallel` type is available.
+            parallel
+        }
+    }
+}
+
+cfg::std! {
+    extern crate std;
+}
+
+cfg::alloc! {
+    extern crate alloc;
+
+    mod map;
+    pub use map::*;
+}
+
+cfg::parallel! {
+    mod parallel_queue;
+    pub use parallel_queue::*;
+}
 
 /// The utilities prelude.
 ///
@@ -27,65 +51,14 @@ pub mod syncunsafecell;
 
 mod default;
 mod once;
-#[cfg(feature = "std")]
-mod parallel_queue;
 
 #[doc(hidden)]
 pub use once::OnceFlag;
 
 pub use default::default;
 
-#[cfg(feature = "std")]
-pub use parallel_queue::*;
-
 use core::mem::ManuallyDrop;
 
-#[cfg(feature = "alloc")]
-use {
-    bevy_platform::{
-        collections::HashMap,
-        hash::{Hashed, NoOpHash, PassHash},
-    },
-    core::{any::TypeId, hash::Hash},
-};
-
-/// A [`HashMap`] pre-configured to use [`Hashed`] keys and [`PassHash`] passthrough hashing.
-/// Iteration order only depends on the order of insertions and deletions.
-#[cfg(feature = "alloc")]
-pub type PreHashMap<K, V> = HashMap<Hashed<K>, V, PassHash>;
-
-/// Extension methods intended to add functionality to [`PreHashMap`].
-#[cfg(feature = "alloc")]
-pub trait PreHashMapExt<K, V> {
-    /// Tries to get or insert the value for the given `key` using the pre-computed hash first.
-    /// If the [`PreHashMap`] does not already contain the `key`, it will clone it and insert
-    /// the value returned by `func`.
-    fn get_or_insert_with<F: FnOnce() -> V>(&mut self, key: &Hashed<K>, func: F) -> &mut V;
-}
-
-#[cfg(feature = "alloc")]
-impl<K: Hash + Eq + PartialEq + Clone, V> PreHashMapExt<K, V> for PreHashMap<K, V> {
-    #[inline]
-    fn get_or_insert_with<F: FnOnce() -> V>(&mut self, key: &Hashed<K>, func: F) -> &mut V {
-        use bevy_platform::collections::hash_map::RawEntryMut;
-        let entry = self
-            .raw_entry_mut()
-            .from_key_hashed_nocheck(key.hash(), key);
-        match entry {
-            RawEntryMut::Occupied(entry) => entry.into_mut(),
-            RawEntryMut::Vacant(entry) => {
-                let (_, value) = entry.insert_hashed_nocheck(key.hash(), key.clone(), func());
-                value
-            }
-        }
-    }
-}
-
-/// A specialized hashmap type with Key of [`TypeId`]
-/// Iteration order only depends on the order of insertions and deletions.
-#[cfg(feature = "alloc")]
-pub type TypeIdMap<V> = HashMap<TypeId, V, NoOpHash>;
-
 /// A type which calls a function when dropped.
 /// This can be used to ensure that cleanup code is run even in case of a panic.
 ///
@@ -144,46 +117,3 @@ impl<F: FnOnce()> Drop for OnDrop<F> {
         callback();
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use static_assertions::assert_impl_all;
-
-    // Check that the HashMaps are Clone if the key/values are Clone
-    assert_impl_all!(PreHashMap::<u64, usize>: Clone);
-
-    #[test]
-    fn fast_typeid_hash() {
-        struct Hasher;
-
-        impl core::hash::Hasher for Hasher {
-            fn finish(&self) -> u64 {
-                0
-            }
-            fn write(&mut self, _: &[u8]) {
-                panic!("Hashing of core::any::TypeId changed");
-            }
-            fn write_u64(&mut self, _: u64) {}
-        }
-
-        Hash::hash(&TypeId::of::<()>(), &mut Hasher);
-    }
-
-    #[cfg(feature = "alloc")]
-    #[test]
-    fn stable_hash_within_same_program_execution() {
-        use alloc::vec::Vec;
-
-        let mut map_1 = <HashMap<_, _>>::default();
-        let mut map_2 = <HashMap<_, _>>::default();
-        for i in 1..10 {
-            map_1.insert(i, i);
-            map_2.insert(i, i);
-        }
-        assert_eq!(
-            map_1.iter().collect::<Vec<_>>(),
-            map_2.iter().collect::<Vec<_>>()
-        );
-    }
-}
diff --git a/crates/bevy_utils/src/map.rs b/crates/bevy_utils/src/map.rs
diff --git a/crates/bevy_utils/src/parallel_queue.rs b/crates/bevy_utils/src/parallel_queue.rs

Original file line number	Diff line number	Diff line change
`@@ -42,7 +42,6 @@ std = [`
`42`	`42`	`"bevy_app/std",`
`43`	`43`	`"bevy_ecs/std",`
`44`	`44`	`"bevy_math/std",`
`45`		`- "bevy_utils/std",`
`46`	`45`	`"bevy_reflect/std",`
`47`	`46`	`"bevy_platform/std",`
`48`	`47`	`]`
Original file line number	Diff line number	Diff line change
`@@ -74,7 +74,7 @@ std = [`
`74`	`74`	`"bevy_math/std",`
`75`	`75`	`"bevy_reflect?/std",`
`76`	`76`	`"bevy_tasks/std",`
`77`		`- "bevy_utils/std",`
	`77`	`+ "bevy_utils/parallel",`
`78`	`78`	`"serde?/std",`
`79`	`79`	`]`
`80`	`80`