Merge branch 'main' into Remove-entity-reserving/pending/flushing-system

.github/workflows/post-release.yml

@@ -49,7 +49,8 @@ jobs:
             --exclude ci \
             --exclude errors \
             --exclude bevy_mobile_example \
-            --exclude build-wasm-example
+            --exclude build-wasm-example \
+            --exclude no_std_library
 
       - name: Create PR
         uses: peter-evans/create-pull-request@v7

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 categories = ["game-engines", "graphics", "gui", "rendering"]
 description = "A refreshingly simple data-driven game engine and app framework"
@@ -72,7 +72,6 @@ allow_attributes_without_reason = "warn"
 
 [workspace.lints.rust]
 missing_docs = "warn"
-mismatched_lifetime_syntaxes = "allow"
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(docsrs_dep)'] }
 unsafe_code = "deny"
 unsafe_op_in_unsafe_fn = "warn"
@@ -559,12 +558,12 @@ hotpatching = ["bevy_internal/hotpatching"]
 debug = ["bevy_internal/debug"]
 
 [dependencies]
-bevy_internal = { path = "crates/bevy_internal", version = "0.16.0-dev", default-features = false }
+bevy_internal = { path = "crates/bevy_internal", version = "0.17.0-dev", default-features = false }
 tracing = { version = "0.1", default-features = false, optional = true }
 
 # Wasm does not support dynamic linking.
 [target.'cfg(not(target_family = "wasm"))'.dependencies]
-bevy_dylib = { path = "crates/bevy_dylib", version = "0.16.0-dev", default-features = false, optional = true }
+bevy_dylib = { path = "crates/bevy_dylib", version = "0.17.0-dev", default-features = false, optional = true }
 
 [dev-dependencies]
 rand = "0.8.0"
@@ -574,14 +573,14 @@ flate2 = "1.0"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1.0.140"
 bytemuck = "1.7"
-bevy_render = { path = "crates/bevy_render", version = "0.16.0-dev", default-features = false }
+bevy_render = { path = "crates/bevy_render", version = "0.17.0-dev", default-features = false }
 # The following explicit dependencies are needed for proc macros to work inside of examples as they are part of the bevy crate itself.
-bevy_ecs = { path = "crates/bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "crates/bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_state = { path = "crates/bevy_state", version = "0.16.0-dev", default-features = false }
+bevy_state = { path = "crates/bevy_state", version = "0.17.0-dev", default-features = false }
-bevy_asset = { path = "crates/bevy_asset", version = "0.16.0-dev", default-features = false }
+bevy_asset = { path = "crates/bevy_asset", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "crates/bevy_reflect", version = "0.16.0-dev", default-features = false }
+bevy_reflect = { path = "crates/bevy_reflect", version = "0.17.0-dev", default-features = false }
-bevy_image = { path = "crates/bevy_image", version = "0.16.0-dev", default-features = false }
+bevy_image = { path = "crates/bevy_image", version = "0.17.0-dev", default-features = false }
-bevy_gizmos = { path = "crates/bevy_gizmos", version = "0.16.0-dev", default-features = false }
+bevy_gizmos = { path = "crates/bevy_gizmos", version = "0.17.0-dev", default-features = false }
 # Needed to poll Task examples
 futures-lite = "2.0.1"
 async-std = "1.13"
@@ -608,7 +607,7 @@ web-sys = { version = "0.3", features = ["Window"] }
 
 [[example]]
 name = "context_menu"
-path = "examples/usages/context_menu.rs"
+path = "examples/usage/context_menu.rs"
 doc-scrape-examples = true
 
 [package.metadata.example.context_menu]
@@ -1285,9 +1284,9 @@ required-features = ["bevy_solari"]
 
 [package.metadata.example.solari]
 name = "Solari"
-description = "Demonstrates realtime dynamic global illumination rendering using Bevy Solari."
+description = "Demonstrates realtime dynamic raytraced lighting using Bevy Solari."
 category = "3D Rendering"
-wasm = false
+wasm = false                                                                        # Raytracing is not supported on the web
 
 [[example]]
 name = "spherical_area_lights"

benches/benches/bevy_ecs/change_detection.rs

@@ -49,6 +49,7 @@ impl BenchModify for Table {
         black_box(self.0)
     }
 }
+
 impl BenchModify for Sparse {
     fn bench_modify(&mut self) -> f32 {
         self.0 += 1f32;

crates/bevy_a11y/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_a11y"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides accessibility support for Bevy Engine"
 homepage = "https://bevy.org"
@@ -40,10 +40,10 @@ critical-section = [
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, optional = true }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, optional = true }
 
 # other
 accesskit = { version = "0.19", default-features = false }

crates/bevy_animation/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_animation"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides animation functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -10,22 +10,22 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_log = { path = "../bevy_log", version = "0.16.0-dev" }
+bevy_log = { path = "../bevy_log", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_mesh = { path = "../bevy_mesh", version = "0.16.0-dev" }
+bevy_mesh = { path = "../bevy_mesh", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", features = [
   "petgraph",
 ] }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev" }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
   "serialize",
 ] }

crates/bevy_anti_aliasing/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_anti_aliasing"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides various anti aliasing implementations for Bevy Engine"
 homepage = "https://bevy.org"
@@ -16,17 +16,17 @@ smaa_luts = ["bevy_render/ktx2", "bevy_image/ktx2", "bevy_image/zstd"]
 
 [dependencies]
 # bevy
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.16.0-dev" }
+bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.17.0-dev" }
-bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.16.0-dev" }
+bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.17.0-dev" }
 
 # other
 tracing = { version = "0.1", default-features = false, features = ["std"] }

crates/bevy_app/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_app"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides core App functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -79,12 +79,12 @@ hotpatching = [
 
 [dependencies]
 # bevy
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, optional = true }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, optional = true }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false }
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false }
 
 # other
 downcast-rs = { version = "2", default-features = false }

crates/bevy_app/src/app.rs

@@ -1582,7 +1582,7 @@ mod tests {
         app.add_systems(EnterMainMenu, (foo, bar));
 
         app.world_mut().run_schedule(EnterMainMenu);
-        assert_eq!(app.world().entities().count_constructed(), 2);
+        assert_eq!(app.world().entity_count(), 2);
     }
 
     #[test]

crates/bevy_app/src/propagate.rs

@@ -88,6 +88,7 @@ impl<C: Component + Clone + PartialEq> core::fmt::Debug for PropagateSet<C> {
 }
 
 impl<C: Component + Clone + PartialEq> Eq for PropagateSet<C> {}
+
 impl<C: Component + Clone + PartialEq> core::hash::Hash for PropagateSet<C> {
     fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
         self._p.hash(state);

crates/bevy_asset/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_asset"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides asset functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -19,19 +19,19 @@ watch = []
 trace = []
 
 [dependencies]
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false, features = [
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_asset_macros = { path = "macros", version = "0.16.0-dev" }
+bevy_asset_macros = { path = "macros", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, features = [
   "uuid",
 ] }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false, features = [
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false, features = [
   "async_executor",
 ] }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
 ] }
 
@@ -65,7 +65,7 @@ uuid = { version = "1.13.1", default-features = false, features = [
 tracing = { version = "0.1", default-features = false }
 
 [target.'cfg(target_os = "android")'.dependencies]
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev" }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 # TODO: Assuming all wasm builds are for the browser. Require `no_std` support to break assumption.
@@ -78,13 +78,13 @@ web-sys = { version = "0.3", features = [
 wasm-bindgen-futures = "0.4"
 js-sys = "0.3"
 uuid = { version = "1.13.1", default-features = false, features = ["js"] }
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false, features = [
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false, features = [
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
 

crates/bevy_asset/macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_asset_macros"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Derive implementations for bevy_asset"
 homepage = "https://bevy.org"
@@ -12,7 +12,7 @@ keywords = ["bevy"]
 proc-macro = true
 
 [dependencies]
-bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.16.0-dev" }
+bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.17.0-dev" }
 
 syn = "2.0"
 proc-macro2 = "1.0"

crates/bevy_asset/src/direct_access_ext.rs

@@ -20,6 +20,7 @@ pub trait DirectAssetAccessExt {
         settings: impl Fn(&mut S) + Send + Sync + 'static,
     ) -> Handle<A>;
 }
+
 impl DirectAssetAccessExt for World {
     /// Insert an asset similarly to [`Assets::add`].
     ///

crates/bevy_asset/src/io/embedded/embedded_watcher.rs

@@ -56,6 +56,7 @@ pub(crate) struct EmbeddedEventHandler {
     dir: Dir,
     last_event: Option<AssetSourceEvent>,
 }
+
 impl FilesystemEventHandler for EmbeddedEventHandler {
     fn begin(&mut self) {
         self.last_event = None;

crates/bevy_asset/src/io/embedded/mod.rs

@@ -141,16 +141,19 @@ impl EmbeddedAssetRegistry {
 pub trait GetAssetServer {
     fn get_asset_server(&self) -> &AssetServer;
 }
+
 impl GetAssetServer for App {
     fn get_asset_server(&self) -> &AssetServer {
         self.world().get_asset_server()
     }
 }
+
 impl GetAssetServer for World {
     fn get_asset_server(&self) -> &AssetServer {
         self.resource()
     }
 }
+
 impl GetAssetServer for AssetServer {
     fn get_asset_server(&self) -> &AssetServer {
         self

crates/bevy_asset/src/reflect.rs

@@ -223,6 +223,7 @@ pub struct ReflectHandle {
     downcast_handle_untyped: fn(&dyn Any) -> Option<UntypedHandle>,
     typed: fn(UntypedHandle) -> Box<dyn Reflect>,
 }
+
 impl ReflectHandle {
     /// The [`TypeId`] of the asset
     pub fn asset_type_id(&self) -> TypeId {

crates/bevy_audio/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_audio"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides audio functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -10,13 +10,13 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
 
 # other
 # TODO: Remove `coreaudio-sys` dep below when updating `cpal`.
@@ -36,10 +36,10 @@ coreaudio-sys = { version = "0.2.17", default-features = false }
 rodio = { version = "0.20", default-features = false, features = [
   "wasm-bindgen",
 ] }
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false, features = [
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
 

crates/bevy_audio/src/audio_output.rs

@@ -57,6 +57,7 @@ pub struct PlaybackRemoveMarker;
 pub(crate) struct EarPositions<'w, 's> {
     pub(crate) query: Query<'w, 's, (Entity, &'static GlobalTransform, &'static SpatialListener)>,
 }
+
 impl<'w, 's> EarPositions<'w, 's> {
     /// Gets a set of transformed ear positions.
     ///

crates/bevy_color/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_color"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Types for representing and manipulating color values"
 homepage = "https://bevy.org"
@@ -10,10 +10,10 @@ keywords = ["bevy", "color"]
 rust-version = "1.85.0"
 
 [dependencies]
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev", default-features = false, features = [
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev", default-features = false, features = [
   "curve",
 ] }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, optional = true }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, optional = true }
 bytemuck = { version = "1", features = ["derive"] }
 serde = { version = "1.0", features = [
   "derive",

crates/bevy_core_pipeline/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_core_pipeline"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 authors = [
   "Bevy Contributors <bevyengine@gmail.com>",
@@ -20,20 +20,20 @@ tonemapping_luts = ["bevy_render/ktx2", "bevy_image/ktx2", "bevy_image/zstd"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.16.0-dev" }
+bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
   "serialize",
 ] }

crates/bevy_core_pipeline/src/core_3d/camera_3d.rs

@@ -80,6 +80,7 @@ impl From<TextureUsages> for Camera3dDepthTextureUsage {
         Self(value.bits())
     }
 }
+
 impl From<Camera3dDepthTextureUsage> for TextureUsages {
     fn from(value: Camera3dDepthTextureUsage) -> Self {
         Self::from_bits_truncate(value.0)

crates/bevy_core_widgets/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_core_widgets"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Unstyled common widgets for Bevy Engine"
 homepage = "https://bevyengine.org"
@@ -10,17 +10,17 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_a11y = { path = "../bevy_a11y", version = "0.16.0-dev" }
+bevy_a11y = { path = "../bevy_a11y", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev" }
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev" }
-bevy_input_focus = { path = "../bevy_input_focus", version = "0.16.0-dev" }
+bevy_input_focus = { path = "../bevy_input_focus", version = "0.17.0-dev" }
-bevy_log = { path = "../bevy_log", version = "0.16.0-dev" }
+bevy_log = { path = "../bevy_log", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_picking = { path = "../bevy_picking", version = "0.16.0-dev" }
+bevy_picking = { path = "../bevy_picking", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_ui = { path = "../bevy_ui", version = "0.16.0-dev", features = [
+bevy_ui = { path = "../bevy_ui", version = "0.17.0-dev", features = [
   "bevy_ui_picking_backend",
 ] }
 

crates/bevy_core_widgets/src/core_button.rs

@@ -2,7 +2,6 @@ use accesskit::Role;
 use bevy_a11y::AccessibilityNode;
 use bevy_app::{App, Plugin};
 use bevy_ecs::query::Has;
-use bevy_ecs::system::ResMut;
 use bevy_ecs::{
     component::Component,
     entity::Entity,
@@ -11,7 +10,8 @@ use bevy_ecs::{
     system::{Commands, Query, SystemId},
 };
 use bevy_input::keyboard::{KeyCode, KeyboardInput};
-use bevy_input_focus::{FocusedInput, InputFocus, InputFocusVisible};
+use bevy_input::ButtonState;
+use bevy_input_focus::FocusedInput;
 use bevy_picking::events::{Cancel, Click, DragEnd, Pointer, Press, Release};
 use bevy_ui::{InteractionDisabled, Pressed};
 
@@ -36,6 +36,7 @@ fn button_on_key_event(
         if !disabled {
             let event = &trigger.event().input;
             if !event.repeat
+                && event.state == ButtonState::Pressed
                 && (event.key_code == KeyCode::Enter || event.key_code == KeyCode::Space)
             {
                 if let Some(on_click) = bstate.on_click {
@@ -65,24 +66,12 @@ fn button_on_pointer_click(
 fn button_on_pointer_down(
     mut trigger: On<Pointer<Press>>,
     mut q_state: Query<(Entity, Has<InteractionDisabled>, Has<Pressed>), With<CoreButton>>,
-    focus: Option<ResMut<InputFocus>>,
-    focus_visible: Option<ResMut<InputFocusVisible>>,
     mut commands: Commands,
 ) {
     if let Ok((button, disabled, pressed)) = q_state.get_mut(trigger.target()) {
         trigger.propagate(false);
-        if !disabled {
+        if !disabled && !pressed {
-            if !pressed {
+            commands.entity(button).insert(Pressed);
-                commands.entity(button).insert(Pressed);
-            }
-            // Clicking on a button makes it the focused input,
-            // and hides the focus ring if it was visible.
-            if let Some(mut focus) = focus {
-                focus.0 = (trigger.target() != Entity::PLACEHOLDER).then_some(trigger.target());
-            }
-            if let Some(mut focus_visible) = focus_visible {
-                focus_visible.0 = false;
-            }
         }
     }
 }

crates/bevy_core_widgets/src/core_checkbox.rs

@@ -0,0 +1,179 @@
+use accesskit::Role;
+use bevy_a11y::AccessibilityNode;
+use bevy_app::{App, Plugin};
+use bevy_ecs::event::{EntityEvent, Event};
+use bevy_ecs::query::{Has, Without};
+use bevy_ecs::system::{In, ResMut};
+use bevy_ecs::{
+    component::Component,
+    observer::On,
+    system::{Commands, Query, SystemId},
+};
+use bevy_input::keyboard::{KeyCode, KeyboardInput};
+use bevy_input::ButtonState;
+use bevy_input_focus::{FocusedInput, InputFocus, InputFocusVisible};
+use bevy_picking::events::{Click, Pointer};
+use bevy_ui::{Checkable, Checked, InteractionDisabled};
+
+/// Headless widget implementation for checkboxes. The [`Checked`] component represents the current
+/// state of the checkbox. The `on_change` field is an optional system id that will be run when the
+/// checkbox is clicked, or when the `Enter` or `Space` key is pressed while the checkbox is
+/// focused. If the `on_change` field is `None`, then instead of calling a callback, the checkbox
+/// will update its own [`Checked`] state directly.
+///
+/// # Toggle switches
+///
+/// The [`CoreCheckbox`] component can be used to implement other kinds of toggle widgets. If you
+/// are going to do a toggle switch, you should override the [`AccessibilityNode`] component with
+/// the `Switch` role instead of the `Checkbox` role.
+#[derive(Component, Debug, Default)]
+#[require(AccessibilityNode(accesskit::Node::new(Role::CheckBox)), Checkable)]
+pub struct CoreCheckbox {
+    /// One-shot system that is run when the checkbox state needs to be changed.
+    pub on_change: Option<SystemId<In<bool>>>,
+}
+
+fn checkbox_on_key_input(
+    mut ev: On<FocusedInput<KeyboardInput>>,
+    q_checkbox: Query<(&CoreCheckbox, Has<Checked>), Without<InteractionDisabled>>,
+    mut commands: Commands,
+) {
+    if let Ok((checkbox, is_checked)) = q_checkbox.get(ev.target()) {
+        let event = &ev.event().input;
+        if event.state == ButtonState::Pressed
+            && !event.repeat
+            && (event.key_code == KeyCode::Enter || event.key_code == KeyCode::Space)
+        {
+            ev.propagate(false);
+            set_checkbox_state(&mut commands, ev.target(), checkbox, !is_checked);
+        }
+    }
+}
+
+fn checkbox_on_pointer_click(
+    mut ev: On<Pointer<Click>>,
+    q_checkbox: Query<(&CoreCheckbox, Has<Checked>, Has<InteractionDisabled>)>,
+    focus: Option<ResMut<InputFocus>>,
+    focus_visible: Option<ResMut<InputFocusVisible>>,
+    mut commands: Commands,
+) {
+    if let Ok((checkbox, is_checked, disabled)) = q_checkbox.get(ev.target()) {
+        // Clicking on a button makes it the focused input,
+        // and hides the focus ring if it was visible.
+        if let Some(mut focus) = focus {
+            focus.0 = Some(ev.target());
+        }
+        if let Some(mut focus_visible) = focus_visible {
+            focus_visible.0 = false;
+        }
+
+        ev.propagate(false);
+        if !disabled {
+            set_checkbox_state(&mut commands, ev.target(), checkbox, !is_checked);
+        }
+    }
+}
+
+/// Event which can be triggered on a checkbox to set the checked state. This can be used to control
+/// the checkbox via gamepad buttons or other inputs.
+///
+/// # Example:
+///
+/// ```
+/// use bevy_ecs::system::Commands;
+/// use bevy_core_widgets::{CoreCheckbox, SetChecked};
+///
+/// fn setup(mut commands: Commands) {
+///     // Create a checkbox
+///     let checkbox = commands.spawn((
+///         CoreCheckbox::default(),
+///     )).id();
+///
+///     // Set to checked
+///     commands.trigger_targets(SetChecked(true), checkbox);
+/// }
+/// ```
+#[derive(Event, EntityEvent)]
+pub struct SetChecked(pub bool);
+
+/// Event which can be triggered on a checkbox to toggle the checked state. This can be used to
+/// control the checkbox via gamepad buttons or other inputs.
+///
+/// # Example:
+///
+/// ```
+/// use bevy_ecs::system::Commands;
+/// use bevy_core_widgets::{CoreCheckbox, ToggleChecked};
+///
+/// fn setup(mut commands: Commands) {
+///     // Create a checkbox
+///     let checkbox = commands.spawn((
+///         CoreCheckbox::default(),
+///     )).id();
+///
+///     // Set to checked
+///     commands.trigger_targets(ToggleChecked, checkbox);
+/// }
+/// ```
+#[derive(Event, EntityEvent)]
+pub struct ToggleChecked;
+
+fn checkbox_on_set_checked(
+    mut ev: On<SetChecked>,
+    q_checkbox: Query<(&CoreCheckbox, Has<Checked>, Has<InteractionDisabled>)>,
+    mut commands: Commands,
+) {
+    if let Ok((checkbox, is_checked, disabled)) = q_checkbox.get(ev.target()) {
+        ev.propagate(false);
+        if disabled {
+            return;
+        }
+
+        let will_be_checked = ev.event().0;
+        if will_be_checked != is_checked {
+            set_checkbox_state(&mut commands, ev.target(), checkbox, will_be_checked);
+        }
+    }
+}
+
+fn checkbox_on_toggle_checked(
+    mut ev: On<ToggleChecked>,
+    q_checkbox: Query<(&CoreCheckbox, Has<Checked>, Has<InteractionDisabled>)>,
+    mut commands: Commands,
+) {
+    if let Ok((checkbox, is_checked, disabled)) = q_checkbox.get(ev.target()) {
+        ev.propagate(false);
+        if disabled {
+            return;
+        }
+
+        set_checkbox_state(&mut commands, ev.target(), checkbox, !is_checked);
+    }
+}
+
+fn set_checkbox_state(
+    commands: &mut Commands,
+    entity: impl Into<bevy_ecs::entity::Entity>,
+    checkbox: &CoreCheckbox,
+    new_state: bool,
+) {
+    if let Some(on_change) = checkbox.on_change {
+        commands.run_system_with(on_change, new_state);
+    } else if new_state {
+        commands.entity(entity.into()).insert(Checked);
+    } else {
+        commands.entity(entity.into()).remove::<Checked>();
+    }
+}
+
+/// Plugin that adds the observers for the [`CoreCheckbox`] widget.
+pub struct CoreCheckboxPlugin;
+
+impl Plugin for CoreCheckboxPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_observer(checkbox_on_key_input)
+            .add_observer(checkbox_on_pointer_click)
+            .add_observer(checkbox_on_set_checked)
+            .add_observer(checkbox_on_toggle_checked);
+    }
+}

crates/bevy_core_widgets/src/core_slider.rs

@@ -3,12 +3,11 @@ use core::ops::RangeInclusive;
 use accesskit::{Orientation, Role};
 use bevy_a11y::AccessibilityNode;
 use bevy_app::{App, Plugin};
-use bevy_ecs::entity::Entity;
 use bevy_ecs::event::{EntityEvent, Event};
-use bevy_ecs::hierarchy::{ChildOf, Children};
+use bevy_ecs::hierarchy::Children;
 use bevy_ecs::lifecycle::Insert;
 use bevy_ecs::query::Has;
-use bevy_ecs::system::{In, Res, ResMut};
+use bevy_ecs::system::{In, Res};
 use bevy_ecs::world::DeferredWorld;
 use bevy_ecs::{
     component::Component,
@@ -18,7 +17,7 @@ use bevy_ecs::{
 };
 use bevy_input::keyboard::{KeyCode, KeyboardInput};
 use bevy_input::ButtonState;
-use bevy_input_focus::{FocusedInput, InputFocus, InputFocusVisible};
+use bevy_input_focus::FocusedInput;
 use bevy_log::warn_once;
 use bevy_picking::events::{Drag, DragEnd, DragStart, Pointer, Press};
 use bevy_ui::{ComputedNode, ComputedNodeTarget, InteractionDisabled, UiGlobalTransform, UiScale};
@@ -207,43 +206,18 @@ pub(crate) fn slider_on_pointer_down(
     )>,
     q_thumb: Query<&ComputedNode, With<CoreSliderThumb>>,
     q_children: Query<&Children>,
-    q_parents: Query<&ChildOf>,
-    focus: Option<ResMut<InputFocus>>,
-    focus_visible: Option<ResMut<InputFocusVisible>>,
     mut commands: Commands,
     ui_scale: Res<UiScale>,
 ) {
     if q_thumb.contains(trigger.target()) {
         // Thumb click, stop propagation to prevent track click.
         trigger.propagate(false);
-
-        // Find the slider entity that's an ancestor of the thumb
-        if let Some(slider_entity) = q_parents
-            .iter_ancestors(trigger.target())
-            .find(|entity| q_slider.contains(*entity))
-        {
-            // Set focus to slider and hide focus ring
-            if let Some(mut focus) = focus {
-                focus.0 = Some(slider_entity);
-            }
-            if let Some(mut focus_visible) = focus_visible {
-                focus_visible.0 = false;
-            }
-        }
     } else if let Ok((slider, value, range, step, node, node_target, transform, disabled)) =
         q_slider.get(trigger.target())
     {
         // Track click
         trigger.propagate(false);
 
-        // Set focus to slider and hide focus ring
-        if let Some(mut focus) = focus {
-            focus.0 = (trigger.target() != Entity::PLACEHOLDER).then_some(trigger.target());
-        }
-        if let Some(mut focus_visible) = focus_visible {
-            focus_visible.0 = false;
-        }
-
         if disabled {
             return;
         }

crates/bevy_core_widgets/src/lib.rs

@@ -15,11 +15,13 @@
 // the widget level, like `SliderValue`, should not have the `Core` prefix.
 
 mod core_button;
+mod core_checkbox;
 mod core_slider;
 
 use bevy_app::{App, Plugin};
 
 pub use core_button::{CoreButton, CoreButtonPlugin};
+pub use core_checkbox::{CoreCheckbox, CoreCheckboxPlugin, SetChecked, ToggleChecked};
 pub use core_slider::{
     CoreSlider, CoreSliderDragState, CoreSliderPlugin, CoreSliderThumb, SetSliderValue,
     SliderRange, SliderStep, SliderValue, TrackClick,
@@ -31,6 +33,6 @@ pub struct CoreWidgetsPlugin;
 
 impl Plugin for CoreWidgetsPlugin {
     fn build(&self, app: &mut App) {
-        app.add_plugins((CoreButtonPlugin, CoreSliderPlugin));
+        app.add_plugins((CoreButtonPlugin, CoreCheckboxPlugin, CoreSliderPlugin));
     }
 }

crates/bevy_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_derive"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides derive implementations for Bevy Engine"
 homepage = "https://bevy.org"
@@ -12,7 +12,7 @@ keywords = ["bevy"]
 proc-macro = true
 
 [dependencies]
-bevy_macro_utils = { path = "../bevy_macro_utils", version = "0.16.0-dev" }
+bevy_macro_utils = { path = "../bevy_macro_utils", version = "0.17.0-dev" }
 
 quote = "1.0"
 syn = { version = "2.0", features = ["full"] }

crates/bevy_dev_tools/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_dev_tools"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Collection of developer tools for the Bevy Engine"
 homepage = "https://bevy.org"
@@ -13,21 +13,21 @@ bevy_ci_testing = ["serde", "ron"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.16.0-dev" }
+bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev" }
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev" }
-bevy_picking = { path = "../bevy_picking", version = "0.16.0-dev" }
+bevy_picking = { path = "../bevy_picking", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev" }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev" }
-bevy_text = { path = "../bevy_text", version = "0.16.0-dev" }
+bevy_text = { path = "../bevy_text", version = "0.17.0-dev" }
-bevy_ui = { path = "../bevy_ui", version = "0.16.0-dev" }
+bevy_ui = { path = "../bevy_ui", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev" }
-bevy_state = { path = "../bevy_state", version = "0.16.0-dev" }
+bevy_state = { path = "../bevy_state", version = "0.17.0-dev" }
 
 # other
 serde = { version = "1.0", features = ["derive"], optional = true }

crates/bevy_diagnostic/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_diagnostic"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides diagnostic functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -53,12 +53,12 @@ critical-section = [
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev", default-features = false }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev", default-features = false }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "alloc",
 ] }
 

crates/bevy_diagnostic/src/frame_time_diagnostics_plugin.rs

@@ -17,11 +17,13 @@ pub struct FrameTimeDiagnosticsPlugin {
     /// The smoothing factor for the exponential moving average. Usually `2.0 / (history_length + 1.0)`.
     pub smoothing_factor: f64,
 }
+
 impl Default for FrameTimeDiagnosticsPlugin {
     fn default() -> Self {
         Self::new(DEFAULT_MAX_HISTORY_LENGTH)
     }
 }
+
 impl FrameTimeDiagnosticsPlugin {
     /// Creates a new `FrameTimeDiagnosticsPlugin` with the specified `max_history_length` and a
     /// reasonable `smoothing_factor`.

crates/bevy_dylib/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_dylib"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Force the Bevy Engine to be dynamically linked for faster linking"
 homepage = "https://bevy.org"
@@ -12,7 +12,7 @@ keywords = ["bevy"]
 crate-type = ["dylib"]
 
 [dependencies]
-bevy_internal = { path = "../bevy_internal", version = "0.16.0-dev", default-features = false }
+bevy_internal = { path = "../bevy_internal", version = "0.17.0-dev", default-features = false }
 
 [lints]
 workspace = true

crates/bevy_ecs/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_ecs"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Bevy Engine's entity component system"
 homepage = "https://bevy.org"
@@ -86,14 +86,14 @@ critical-section = [
 hotpatching = ["dep:subsecond"]
 
 [dependencies]
-bevy_ptr = { path = "../bevy_ptr", version = "0.16.0-dev" }
+bevy_ptr = { path = "../bevy_ptr", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", features = [
   "smallvec",
 ], default-features = false, optional = true }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_ecs_macros = { path = "macros", version = "0.16.0-dev" }
+bevy_ecs_macros = { path = "macros", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "alloc",
 ] }
 

crates/bevy_ecs/macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_ecs_macros"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 description = "Bevy ECS Macros"
 edition = "2024"
 license = "MIT OR Apache-2.0"
@@ -9,7 +9,7 @@ license = "MIT OR Apache-2.0"
 proc-macro = true
 
 [dependencies]
-bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.16.0-dev" }
+bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.17.0-dev" }
 
 syn = { version = "2.0.99", features = ["full", "extra-traits"] }
 quote = "1.0"

crates/bevy_ecs/macros/src/component.rs

@@ -792,6 +792,11 @@ fn derive_relationship(
                     #relationship_member: entity
                 }
             }
+
+            #[inline]
+            fn set_risky(&mut self, entity: Entity) {
+                self.#relationship_member = entity;
+            }
         }
     }))
 }

crates/bevy_ecs/macros/src/lib.rs

@@ -16,7 +16,7 @@ use crate::{
 use bevy_macro_utils::{derive_label, ensure_no_collision, get_struct_fields, BevyManifest};
 use proc_macro::TokenStream;
 use proc_macro2::{Ident, Span};
-use quote::{format_ident, quote};
+use quote::{format_ident, quote, ToTokens};
 use syn::{
     parse_macro_input, parse_quote, punctuated::Punctuated, spanned::Spanned, token::Comma,
     ConstParam, Data, DataStruct, DeriveInput, GenericParam, Index, TypeParam,
@@ -79,6 +79,8 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
     let mut field_kind = Vec::with_capacity(named_fields.len());
 
     for field in named_fields {
+        let mut kind = BundleFieldKind::Component;
+
         for attr in field
             .attrs
             .iter()
@@ -86,7 +88,7 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
         {
             if let Err(error) = attr.parse_nested_meta(|meta| {
                 if meta.path.is_ident(BUNDLE_ATTRIBUTE_IGNORE_NAME) {
-                    field_kind.push(BundleFieldKind::Ignore);
+                    kind = BundleFieldKind::Ignore;
                     Ok(())
                 } else {
                     Err(meta.error(format!(
@@ -98,7 +100,7 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
             }
         }
 
-        field_kind.push(BundleFieldKind::Component);
+        field_kind.push(kind);
     }
 
     let field = named_fields
@@ -111,82 +113,33 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
         .map(|field| &field.ty)
         .collect::<Vec<_>>();
 
-    let mut field_component_ids = Vec::new();
+    let mut active_field_types = Vec::new();
-    let mut field_get_component_ids = Vec::new();
+    let mut active_field_tokens = Vec::new();
-    let mut field_get_components = Vec::new();
+    let mut inactive_field_tokens = Vec::new();
-    let mut field_from_components = Vec::new();
-    let mut field_required_components = Vec::new();
     for (((i, field_type), field_kind), field) in field_type
         .iter()
         .enumerate()
         .zip(field_kind.iter())
         .zip(field.iter())
     {
+        let field_tokens = match field {
+            Some(field) => field.to_token_stream(),
+            None => Index::from(i).to_token_stream(),
+        };
         match field_kind {
             BundleFieldKind::Component => {
-                field_component_ids.push(quote! {
+                active_field_types.push(field_type);
-                <#field_type as #ecs_path::bundle::Bundle>::component_ids(components, &mut *ids);
+                active_field_tokens.push(field_tokens);
-                });
-                field_required_components.push(quote! {
-                    <#field_type as #ecs_path::bundle::Bundle>::register_required_components(components, required_components);
-                });
-                field_get_component_ids.push(quote! {
-                    <#field_type as #ecs_path::bundle::Bundle>::get_component_ids(components, &mut *ids);
-                });
-                match field {
-                    Some(field) => {
-                        field_get_components.push(quote! {
-                            self.#field.get_components(&mut *func);
-                        });
-                        field_from_components.push(quote! {
-                            #field: <#field_type as #ecs_path::bundle::BundleFromComponents>::from_components(ctx, &mut *func),
-                        });
-                    }
-                    None => {
-                        let index = Index::from(i);
-                        field_get_components.push(quote! {
-                            self.#index.get_components(&mut *func);
-                        });
-                        field_from_components.push(quote! {
-                            #index: <#field_type as #ecs_path::bundle::BundleFromComponents>::from_components(ctx, &mut *func),
-                        });
-                    }
-                }
             }
 
-            BundleFieldKind::Ignore => {
+            BundleFieldKind::Ignore => inactive_field_tokens.push(field_tokens),
-                field_from_components.push(quote! {
-                    #field: ::core::default::Default::default(),
-                });
-            }
         }
     }
     let generics = ast.generics;
     let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
     let struct_name = &ast.ident;
 
-    let from_components = attributes.impl_from_components.then(|| quote! {
+    let bundle_impl = quote! {
-        // SAFETY:
-        // - ComponentId is returned in field-definition-order. [from_components] uses field-definition-order
-        #[allow(deprecated)]
-        unsafe impl #impl_generics #ecs_path::bundle::BundleFromComponents for #struct_name #ty_generics #where_clause {
-            #[allow(unused_variables, non_snake_case)]
-            unsafe fn from_components<__T, __F>(ctx: &mut __T, func: &mut __F) -> Self
-            where
-                __F: FnMut(&mut __T) -> #ecs_path::ptr::OwningPtr<'_>
-            {
-                Self{
-                    #(#field_from_components)*
-                }
-            }
-        }
-    });
-
-    let attribute_errors = &errors;
-
-    TokenStream::from(quote! {
-        #(#attribute_errors)*
-
         // SAFETY:
         // - ComponentId is returned in field-definition-order. [get_components] uses field-definition-order
         // - `Bundle::get_components` is exactly once for each member. Rely's on the Component -> Bundle implementation to properly pass
@@ -196,27 +149,27 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
             fn component_ids(
                 components: &mut #ecs_path::component::ComponentsRegistrator,
                 ids: &mut impl FnMut(#ecs_path::component::ComponentId)
-            ){
+            ) {
-                #(#field_component_ids)*
+                #(<#active_field_types as #ecs_path::bundle::Bundle>::component_ids(components, ids);)*
             }
 
             fn get_component_ids(
                 components: &#ecs_path::component::Components,
                 ids: &mut impl FnMut(Option<#ecs_path::component::ComponentId>)
-            ){
+            ) {
-                #(#field_get_component_ids)*
+                #(<#active_field_types as #ecs_path::bundle::Bundle>::get_component_ids(components, &mut *ids);)*
             }
 
             fn register_required_components(
                 components: &mut #ecs_path::component::ComponentsRegistrator,
                 required_components: &mut #ecs_path::component::RequiredComponents
-            ){
+            ) {
-                #(#field_required_components)*
+                #(<#active_field_types as #ecs_path::bundle::Bundle>::register_required_components(components, required_components);)*
             }
         }
+    };
 
-        #from_components
+    let dynamic_bundle_impl = quote! {
-
         #[allow(deprecated)]
         impl #impl_generics #ecs_path::bundle::DynamicBundle for #struct_name #ty_generics #where_clause {
             type Effect = ();
@@ -226,9 +179,36 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
                 self,
                 func: &mut impl FnMut(#ecs_path::component::StorageType, #ecs_path::ptr::OwningPtr<'_>)
             ) {
-                #(#field_get_components)*
+                #(<#active_field_types as #ecs_path::bundle::DynamicBundle>::get_components(self.#active_field_tokens, &mut *func);)*
             }
         }
+    };
+
+    let from_components_impl = attributes.impl_from_components.then(|| quote! {
+        // SAFETY:
+        // - ComponentId is returned in field-definition-order. [from_components] uses field-definition-order
+        #[allow(deprecated)]
+        unsafe impl #impl_generics #ecs_path::bundle::BundleFromComponents for #struct_name #ty_generics #where_clause {
+            #[allow(unused_variables, non_snake_case)]
+            unsafe fn from_components<__T, __F>(ctx: &mut __T, func: &mut __F) -> Self
+            where
+                __F: FnMut(&mut __T) -> #ecs_path::ptr::OwningPtr<'_>
+            {
+                Self {
+                    #(#active_field_tokens: <#active_field_types as #ecs_path::bundle::BundleFromComponents>::from_components(ctx, &mut *func),)*
+                    #(#inactive_field_tokens: ::core::default::Default::default(),)*
+                }
+            }
+        }
+    });
+
+    let attribute_errors = &errors;
+
+    TokenStream::from(quote! {
+        #(#attribute_errors)*
+        #bundle_impl
+        #from_components_impl
+        #dynamic_bundle_impl
     })
 }
 

crates/bevy_ecs/macros/src/query_data.rs

@@ -83,7 +83,7 @@ pub fn derive_query_data_impl(input: TokenStream) -> TokenStream {
     let user_generics_with_world_and_state = {
         let mut generics = ast.generics;
         generics.params.insert(0, parse_quote!('__w));
-        generics.params.insert(0, parse_quote!('__s));
+        generics.params.insert(1, parse_quote!('__s));
         generics
     };
     let (

crates/bevy_ecs/src/archetype.rs

@@ -960,6 +960,7 @@ impl Index<RangeFrom<ArchetypeGeneration>> for Archetypes {
         &self.archetypes[index.start.0.index()..]
     }
 }
+
 impl Index<ArchetypeId> for Archetypes {
     type Output = Archetype;
 

crates/bevy_ecs/src/bundle.rs

@@ -2410,4 +2410,13 @@ mod tests {
 
         assert_eq!(world.resource::<Count>().0, 3);
     }
+
+    #[derive(Bundle)]
+    #[expect(unused, reason = "tests the output of the derive macro is valid")]
+    struct Ignore {
+        #[bundle(ignore)]
+        foo: i32,
+        #[bundle(ignore)]
+        bar: i32,
+    }
 }

crates/bevy_ecs/src/component.rs

@@ -623,6 +623,7 @@ pub trait ComponentMutability: private::Seal + 'static {
 pub struct Immutable;
 
 impl private::Seal for Immutable {}
+
 impl ComponentMutability for Immutable {
     const MUTABLE: bool = false;
 }
@@ -633,6 +634,7 @@ impl ComponentMutability for Immutable {
 pub struct Mutable;
 
 impl private::Seal for Mutable {}
+
 impl ComponentMutability for Mutable {
     const MUTABLE: bool = true;
 }
@@ -2968,6 +2970,7 @@ impl<T> Default for DefaultCloneBehaviorSpecialization<T> {
 pub trait DefaultCloneBehaviorBase {
     fn default_clone_behavior(&self) -> ComponentCloneBehavior;
 }
+
 impl<C> DefaultCloneBehaviorBase for DefaultCloneBehaviorSpecialization<C> {
     fn default_clone_behavior(&self) -> ComponentCloneBehavior {
         ComponentCloneBehavior::Default
@@ -2979,6 +2982,7 @@ impl<C> DefaultCloneBehaviorBase for DefaultCloneBehaviorSpecialization<C> {
 pub trait DefaultCloneBehaviorViaClone {
     fn default_clone_behavior(&self) -> ComponentCloneBehavior;
 }
+
 impl<C: Clone + Component> DefaultCloneBehaviorViaClone for &DefaultCloneBehaviorSpecialization<C> {
     fn default_clone_behavior(&self) -> ComponentCloneBehavior {
         ComponentCloneBehavior::clone::<C>()

crates/bevy_ecs/src/entity/mod.rs

@@ -866,6 +866,7 @@ impl<'a> Iterator for AllocEntitiesIterator<'a> {
 }
 
 impl<'a> ExactSizeIterator for AllocEntitiesIterator<'a> {}
+
 impl<'a> core::iter::FusedIterator for AllocEntitiesIterator<'a> {}
 
 // SAFETY: Newly allocated entity values are unique.

crates/bevy_ecs/src/entity/unique_array.rs

@@ -154,6 +154,7 @@ impl<T: EntityEquivalent, const N: usize> DerefMut for UniqueEntityEquivalentArr
         unsafe { UniqueEntityEquivalentSlice::from_slice_unchecked_mut(&mut self.0) }
     }
 }
+
 impl<T: EntityEquivalent> Default for UniqueEntityEquivalentArray<T, 0> {
     fn default() -> Self {
         Self(Default::default())
@@ -527,6 +528,7 @@ impl<T: PartialEq<U>, U: EntityEquivalent, const N: usize>
         self.eq(&other.0)
     }
 }
+
 impl<T: PartialEq<U>, U: EntityEquivalent, const N: usize>
     PartialEq<&UniqueEntityEquivalentArray<U, N>> for VecDeque<T>
 {
@@ -550,6 +552,7 @@ impl<T: PartialEq<U>, U: EntityEquivalent, const N: usize>
         self.eq(&other.0)
     }
 }
+
 impl<T: PartialEq<U>, U: EntityEquivalent, const N: usize>
     PartialEq<UniqueEntityEquivalentArray<U, N>> for VecDeque<T>
 {

crates/bevy_ecs/src/lib.rs

@@ -1592,9 +1592,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Attempted to access or drop non-send resource bevy_ecs::tests::NonSendA from thread"
-    )]
     fn non_send_resource_drop_from_different_thread() {
         let mut world = World::default();
         world.insert_non_send_resource(NonSendA::default());
@@ -1659,7 +1657,7 @@ mod tests {
 
         assert_eq!(q1.iter(&world).len(), 1);
         assert_eq!(q2.iter(&world).len(), 1);
-        assert_eq!(world.entities().count_constructed(), 2);
+        assert_eq!(world.entity_count(), 2);
 
         world.clear_entities();
 
@@ -1674,7 +1672,7 @@ mod tests {
             "world should not contain sparse set components"
         );
         assert_eq!(
-            world.entities().count_constructed(),
+            world.entity_count(),
             0,
             "world should not have any entities"
         );
@@ -2609,7 +2607,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "Recursive required components detected: A → B → C → B\nhelp: If this is intentional, consider merging the components."]
+    #[should_panic]
     fn required_components_recursion_errors() {
         #[derive(Component, Default)]
         #[require(B)]
@@ -2627,7 +2625,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "Recursive required components detected: A → A\nhelp: Remove require(A)."]
+    #[should_panic]
     fn required_components_self_errors() {
         #[derive(Component, Default)]
         #[require(A)]

crates/bevy_ecs/src/name.rs

@@ -159,6 +159,7 @@ impl From<&str> for Name {
         Name::new(name.to_owned())
     }
 }
+
 impl From<String> for Name {
     #[inline(always)]
     fn from(name: String) -> Self {
@@ -174,12 +175,14 @@ impl AsRef<str> for Name {
         &self.name
     }
 }
+
 impl From<&Name> for String {
     #[inline(always)]
     fn from(val: &Name) -> String {
         val.as_str().to_owned()
     }
 }
+
 impl From<Name> for String {
     #[inline(always)]
     fn from(val: Name) -> String {

crates/bevy_ecs/src/observer/centralized_storage.rs

@@ -0,0 +1,245 @@
+//! Centralized storage for observers, allowing for efficient look-ups.
+//!
+//! This has multiple levels:
+//! - [`World::observers`] provides access to [`Observers`], which is a central storage for all observers.
+//! - [`Observers`] contains multiple distinct caches in the form of [`CachedObservers`].
+//!     - Most observers are looked up by the [`ComponentId`] of the event they are observing
+//!     - Lifecycle observers have their own fields to save lookups.
+//! - [`CachedObservers`] contains maps of [`ObserverRunner`]s, which are the actual functions that will be run when the observer is triggered.
+//!     - These are split by target type, in order to allow for different lookup strategies.
+//!     - [`CachedComponentObservers`] is one of these maps, which contains observers that are specifically targeted at a component.
+
+use bevy_platform::collections::HashMap;
+
+use crate::{
+    archetype::ArchetypeFlags,
+    change_detection::MaybeLocation,
+    component::ComponentId,
+    entity::EntityHashMap,
+    observer::{ObserverRunner, ObserverTrigger},
+    prelude::*,
+    world::DeferredWorld,
+};
+
+/// An internal lookup table tracking all of the observers in the world.
+///
+/// Stores a cache mapping trigger ids to the registered observers.
+/// Some observer kinds (like [lifecycle](crate::lifecycle) observers) have a dedicated field,
+/// saving lookups for the most common triggers.
+///
+/// This can be accessed via [`World::observers`].
+#[derive(Default, Debug)]
+pub struct Observers {
+    // Cached ECS observers to save a lookup most common triggers.
+    add: CachedObservers,
+    insert: CachedObservers,
+    replace: CachedObservers,
+    remove: CachedObservers,
+    despawn: CachedObservers,
+    // Map from trigger type to set of observers listening to that trigger
+    cache: HashMap<ComponentId, CachedObservers>,
+}
+
+impl Observers {
+    pub(crate) fn get_observers_mut(&mut self, event_type: ComponentId) -> &mut CachedObservers {
+        use crate::lifecycle::*;
+
+        match event_type {
+            ADD => &mut self.add,
+            INSERT => &mut self.insert,
+            REPLACE => &mut self.replace,
+            REMOVE => &mut self.remove,
+            DESPAWN => &mut self.despawn,
+            _ => self.cache.entry(event_type).or_default(),
+        }
+    }
+
+    /// Attempts to get the observers for the given `event_type`.
+    ///
+    /// When accessing the observers for lifecycle events, such as [`Add`], [`Insert`], [`Replace`], [`Remove`], and [`Despawn`],
+    /// use the [`ComponentId`] constants from the [`lifecycle`](crate::lifecycle) module.
+    pub fn try_get_observers(&self, event_type: ComponentId) -> Option<&CachedObservers> {
+        use crate::lifecycle::*;
+
+        match event_type {
+            ADD => Some(&self.add),
+            INSERT => Some(&self.insert),
+            REPLACE => Some(&self.replace),
+            REMOVE => Some(&self.remove),
+            DESPAWN => Some(&self.despawn),
+            _ => self.cache.get(&event_type),
+        }
+    }
+
+    /// This will run the observers of the given `event_type`, targeting the given `entity` and `components`.
+    pub(crate) fn invoke<T>(
+        mut world: DeferredWorld,
+        event_type: ComponentId,
+        current_target: Option<Entity>,
+        original_target: Option<Entity>,
+        components: impl Iterator<Item = ComponentId> + Clone,
+        data: &mut T,
+        propagate: &mut bool,
+        caller: MaybeLocation,
+    ) {
+        // SAFETY: You cannot get a mutable reference to `observers` from `DeferredWorld`
+        let (mut world, observers) = unsafe {
+            let world = world.as_unsafe_world_cell();
+            // SAFETY: There are no outstanding world references
+            world.increment_trigger_id();
+            let observers = world.observers();
+            let Some(observers) = observers.try_get_observers(event_type) else {
+                return;
+            };
+            // SAFETY: The only outstanding reference to world is `observers`
+            (world.into_deferred(), observers)
+        };
+
+        let trigger_for_components = components.clone();
+
+        let mut trigger_observer = |(&observer, runner): (&Entity, &ObserverRunner)| {
+            (runner)(
+                world.reborrow(),
+                ObserverTrigger {
+                    observer,
+                    event_type,
+                    components: components.clone().collect(),
+                    current_target,
+                    original_target,
+                    caller,
+                },
+                data.into(),
+                propagate,
+            );
+        };
+        // Trigger observers listening for any kind of this trigger
+        observers
+            .global_observers
+            .iter()
+            .for_each(&mut trigger_observer);
+
+        // Trigger entity observers listening for this kind of trigger
+        if let Some(target_entity) = current_target {
+            if let Some(map) = observers.entity_observers.get(&target_entity) {
+                map.iter().for_each(&mut trigger_observer);
+            }
+        }
+
+        // Trigger observers listening to this trigger targeting a specific component
+        trigger_for_components.for_each(|id| {
+            if let Some(component_observers) = observers.component_observers.get(&id) {
+                component_observers
+                    .global_observers
+                    .iter()
+                    .for_each(&mut trigger_observer);
+
+                if let Some(target_entity) = current_target {
+                    if let Some(map) = component_observers
+                        .entity_component_observers
+                        .get(&target_entity)
+                    {
+                        map.iter().for_each(&mut trigger_observer);
+                    }
+                }
+            }
+        });
+    }
+
+    pub(crate) fn is_archetype_cached(event_type: ComponentId) -> Option<ArchetypeFlags> {
+        use crate::lifecycle::*;
+
+        match event_type {
+            ADD => Some(ArchetypeFlags::ON_ADD_OBSERVER),
+            INSERT => Some(ArchetypeFlags::ON_INSERT_OBSERVER),
+            REPLACE => Some(ArchetypeFlags::ON_REPLACE_OBSERVER),
+            REMOVE => Some(ArchetypeFlags::ON_REMOVE_OBSERVER),
+            DESPAWN => Some(ArchetypeFlags::ON_DESPAWN_OBSERVER),
+            _ => None,
+        }
+    }
+
+    pub(crate) fn update_archetype_flags(
+        &self,
+        component_id: ComponentId,
+        flags: &mut ArchetypeFlags,
+    ) {
+        if self.add.component_observers.contains_key(&component_id) {
+            flags.insert(ArchetypeFlags::ON_ADD_OBSERVER);
+        }
+
+        if self.insert.component_observers.contains_key(&component_id) {
+            flags.insert(ArchetypeFlags::ON_INSERT_OBSERVER);
+        }
+
+        if self.replace.component_observers.contains_key(&component_id) {
+            flags.insert(ArchetypeFlags::ON_REPLACE_OBSERVER);
+        }
+
+        if self.remove.component_observers.contains_key(&component_id) {
+            flags.insert(ArchetypeFlags::ON_REMOVE_OBSERVER);
+        }
+
+        if self.despawn.component_observers.contains_key(&component_id) {
+            flags.insert(ArchetypeFlags::ON_DESPAWN_OBSERVER);
+        }
+    }
+}
+
+/// Collection of [`ObserverRunner`] for [`Observer`] registered to a particular event.
+///
+/// This is stored inside of [`Observers`], specialized for each kind of observer.
+#[derive(Default, Debug)]
+pub struct CachedObservers {
+    // Observers listening for any time this event is fired, regardless of target
+    // This will also respond to events targeting specific components or entities
+    pub(super) global_observers: ObserverMap,
+    // Observers listening for this trigger fired at a specific component
+    pub(super) component_observers: HashMap<ComponentId, CachedComponentObservers>,
+    // Observers listening for this trigger fired at a specific entity
+    pub(super) entity_observers: EntityHashMap<ObserverMap>,
+}
+
+impl CachedObservers {
+    /// Returns the observers listening for this trigger, regardless of target.
+    /// These observers will also respond to events targeting specific components or entities.
+    pub fn global_observers(&self) -> &ObserverMap {
+        &self.global_observers
+    }
+
+    /// Returns the observers listening for this trigger targeting components.
+    pub fn get_component_observers(&self) -> &HashMap<ComponentId, CachedComponentObservers> {
+        &self.component_observers
+    }
+
+    /// Returns the observers listening for this trigger targeting entities.
+    pub fn entity_observers(&self) -> &HashMap<ComponentId, CachedComponentObservers> {
+        &self.component_observers
+    }
+}
+
+/// Map between an observer entity and its [`ObserverRunner`]
+pub type ObserverMap = EntityHashMap<ObserverRunner>;
+
+/// Collection of [`ObserverRunner`] for [`Observer`] registered to a particular event targeted at a specific component.
+///
+/// This is stored inside of [`CachedObservers`].
+#[derive(Default, Debug)]
+pub struct CachedComponentObservers {
+    // Observers listening to events targeting this component, but not a specific entity
+    pub(super) global_observers: ObserverMap,
+    // Observers listening to events targeting this component on a specific entity
+    pub(super) entity_component_observers: EntityHashMap<ObserverMap>,
+}
+
+impl CachedComponentObservers {
+    /// Returns the observers listening for this trigger, regardless of target.
+    /// These observers will also respond to events targeting specific entities.
+    pub fn global_observers(&self) -> &ObserverMap {
+        &self.global_observers
+    }
+
+    /// Returns the observers listening for this trigger targeting this component on a specific entity.
+    pub fn entity_component_observers(&self) -> &EntityHashMap<ObserverMap> {
+        &self.entity_component_observers
+    }
+}

crates/bevy_ecs/src/observer/distributed_storage.rs

@@ -0,0 +1,492 @@
+//! Information about observers that is stored on the entities themselves.
+//!
+//! This allows for easier cleanup, better inspection, and more flexible querying.
+//!
+//! Each observer is associated with an entity, defined by the [`Observer`] component.
+//! The [`Observer`] component contains the system that will be run when the observer is triggered,
+//! and the [`ObserverDescriptor`] which contains information about what the observer is observing.
+//!
+//! When we watch entities, we add the [`ObservedBy`] component to those entities,
+//! which links back to the observer entity.
+
+use core::any::Any;
+
+use crate::{
+    component::{ComponentCloneBehavior, ComponentId, Mutable, StorageType},
+    entity::Entity,
+    error::{ErrorContext, ErrorHandler},
+    lifecycle::{ComponentHook, HookContext},
+    observer::{observer_system_runner, ObserverRunner},
+    prelude::*,
+    system::{IntoObserverSystem, ObserverSystem},
+    world::DeferredWorld,
+};
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use bevy_utils::prelude::DebugName;
+
+#[cfg(feature = "bevy_reflect")]
+use crate::prelude::ReflectComponent;
+
+/// An [`Observer`] system. Add this [`Component`] to an [`Entity`] to turn it into an "observer".
+///
+/// Observers listen for a "trigger" of a specific [`Event`]. An event can be triggered on the [`World`]
+/// by calling [`World::trigger`], or if the event is an [`EntityEvent`], it can also be triggered for specific
+/// entity targets using [`World::trigger_targets`].
+///
+/// Note that [`BufferedEvent`]s sent using [`EventReader`] and [`EventWriter`] are _not_ automatically triggered.
+/// They must be triggered at a specific point in the schedule.
+///
+/// # Usage
+///
+/// The simplest usage of the observer pattern looks like this:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// #[derive(Event)]
+/// struct Speak {
+///     message: String,
+/// }
+///
+/// world.add_observer(|trigger: On<Speak>| {
+///     println!("{}", trigger.event().message);
+/// });
+///
+/// // Observers currently require a flush() to be registered. In the context of schedules,
+/// // this will generally be done for you.
+/// world.flush();
+///
+/// world.trigger(Speak {
+///     message: "Hello!".into(),
+/// });
+/// ```
+///
+/// Notice that we used [`World::add_observer`]. This is just a shorthand for spawning an [`Observer`] manually:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # #[derive(Event)]
+/// # struct Speak;
+/// // These are functionally the same:
+/// world.add_observer(|trigger: On<Speak>| {});
+/// world.spawn(Observer::new(|trigger: On<Speak>| {}));
+/// ```
+///
+/// Observers are systems. They can access arbitrary [`World`] data by adding [`SystemParam`]s:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # #[derive(Event)]
+/// # struct PrintNames;
+/// # #[derive(Component, Debug)]
+/// # struct Name;
+/// world.add_observer(|trigger: On<PrintNames>, names: Query<&Name>| {
+///     for name in &names {
+///         println!("{name:?}");
+///     }
+/// });
+/// ```
+///
+/// Note that [`On`] must always be the first parameter.
+///
+/// You can also add [`Commands`], which means you can spawn new entities, insert new components, etc:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # #[derive(Event)]
+/// # struct SpawnThing;
+/// # #[derive(Component, Debug)]
+/// # struct Thing;
+/// world.add_observer(|trigger: On<SpawnThing>, mut commands: Commands| {
+///     commands.spawn(Thing);
+/// });
+/// ```
+///
+/// Observers can also trigger new events:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # #[derive(Event)]
+/// # struct A;
+/// # #[derive(Event)]
+/// # struct B;
+/// world.add_observer(|trigger: On<A>, mut commands: Commands| {
+///     commands.trigger(B);
+/// });
+/// ```
+///
+/// When the commands are flushed (including these "nested triggers") they will be
+/// recursively evaluated until there are no commands left, meaning nested triggers all
+/// evaluate at the same time!
+///
+/// If the event is an [`EntityEvent`], it can be triggered for specific entities,
+/// which will be passed to the [`Observer`]:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # let entity = world.spawn_empty().id();
+/// #[derive(Event, EntityEvent)]
+/// struct Explode;
+///
+/// world.add_observer(|trigger: On<Explode>, mut commands: Commands| {
+///     println!("Entity {} goes BOOM!", trigger.target());
+///     commands.entity(trigger.target()).despawn();
+/// });
+///
+/// world.flush();
+///
+/// world.trigger_targets(Explode, entity);
+/// ```
+///
+/// You can trigger multiple entities at once:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # let e1 = world.spawn_empty().id();
+/// # let e2 = world.spawn_empty().id();
+/// # #[derive(Event, EntityEvent)]
+/// # struct Explode;
+/// world.trigger_targets(Explode, [e1, e2]);
+/// ```
+///
+/// Observers can also watch _specific_ entities, which enables you to assign entity-specific logic:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # #[derive(Component, Debug)]
+/// # struct Name(String);
+/// # let mut world = World::default();
+/// # let e1 = world.spawn_empty().id();
+/// # let e2 = world.spawn_empty().id();
+/// # #[derive(Event, EntityEvent)]
+/// # struct Explode;
+/// world.entity_mut(e1).observe(|trigger: On<Explode>, mut commands: Commands| {
+///     println!("Boom!");
+///     commands.entity(trigger.target()).despawn();
+/// });
+///
+/// world.entity_mut(e2).observe(|trigger: On<Explode>, mut commands: Commands| {
+///     println!("The explosion fizzles! This entity is immune!");
+/// });
+/// ```
+///
+/// If all entities watched by a given [`Observer`] are despawned, the [`Observer`] entity will also be despawned.
+/// This protects against observer "garbage" building up over time.
+///
+/// The examples above calling [`EntityWorldMut::observe`] to add entity-specific observer logic are (once again)
+/// just shorthand for spawning an [`Observer`] directly:
+///
+/// ```
+/// # use bevy_ecs::prelude::*;
+/// # let mut world = World::default();
+/// # let entity = world.spawn_empty().id();
+/// # #[derive(Event, EntityEvent)]
+/// # struct Explode;
+/// let mut observer = Observer::new(|trigger: On<Explode>| {});
+/// observer.watch_entity(entity);
+/// world.spawn(observer);
+/// ```
+///
+/// Note that the [`Observer`] component is not added to the entity it is observing. Observers should always be their own entities!
+///
+/// You can call [`Observer::watch_entity`] more than once, which allows you to watch multiple entities with the same [`Observer`].
+/// serves as the "source of truth" of the observer.
+///
+/// [`SystemParam`]: crate::system::SystemParam
+pub struct Observer {
+    hook_on_add: ComponentHook,
+    pub(crate) error_handler: Option<ErrorHandler>,
+    pub(crate) system: Box<dyn AnyNamedSystem>,
+    pub(crate) descriptor: ObserverDescriptor,
+    pub(crate) last_trigger_id: u32,
+    pub(crate) despawned_watched_entities: u32,
+    pub(crate) runner: ObserverRunner,
+}
+
+impl Observer {
+    /// Creates a new [`Observer`], which defaults to a "global" observer. This means it will run whenever the event `E` is triggered
+    /// for _any_ entity (or no entity).
+    ///
+    /// # Panics
+    ///
+    /// Panics if the given system is an exclusive system.
+    pub fn new<E: Event, B: Bundle, M, I: IntoObserverSystem<E, B, M>>(system: I) -> Self {
+        let system = Box::new(IntoObserverSystem::into_system(system));
+        assert!(
+            !system.is_exclusive(),
+            concat!(
+                "Exclusive system `{}` may not be used as observer.\n",
+                "Instead of `&mut World`, use either `DeferredWorld` if you do not need structural changes, or `Commands` if you do."
+            ),
+            system.name()
+        );
+        Self {
+            system,
+            descriptor: Default::default(),
+            hook_on_add: hook_on_add::<E, B, I::System>,
+            error_handler: None,
+            runner: observer_system_runner::<E, B, I::System>,
+            despawned_watched_entities: 0,
+            last_trigger_id: 0,
+        }
+    }
+
+    /// Creates a new [`Observer`] with custom runner, this is mostly used for dynamic event observer
+    pub fn with_dynamic_runner(runner: ObserverRunner) -> Self {
+        Self {
+            system: Box::new(IntoSystem::into_system(|| {})),
+            descriptor: Default::default(),
+            hook_on_add: |mut world, hook_context| {
+                let default_error_handler = world.default_error_handler();
+                world.commands().queue(move |world: &mut World| {
+                    let entity = hook_context.entity;
+                    if let Some(mut observe) = world.get_mut::<Observer>(entity) {
+                        if observe.descriptor.events.is_empty() {
+                            return;
+                        }
+                        if observe.error_handler.is_none() {
+                            observe.error_handler = Some(default_error_handler);
+                        }
+                        world.register_observer(entity);
+                    }
+                });
+            },
+            error_handler: None,
+            runner,
+            despawned_watched_entities: 0,
+            last_trigger_id: 0,
+        }
+    }
+
+    /// Observe the given `entity`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
+    /// for the `entity`.
+    pub fn with_entity(mut self, entity: Entity) -> Self {
+        self.descriptor.entities.push(entity);
+        self
+    }
+
+    /// Observe the given `entity`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
+    /// for the `entity`.
+    /// Note that if this is called _after_ an [`Observer`] is spawned, it will produce no effects.
+    pub fn watch_entity(&mut self, entity: Entity) {
+        self.descriptor.entities.push(entity);
+    }
+
+    /// Observe the given `component`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
+    /// with the given component target.
+    pub fn with_component(mut self, component: ComponentId) -> Self {
+        self.descriptor.components.push(component);
+        self
+    }
+
+    /// Observe the given `event`. This will cause the [`Observer`] to run whenever an event with the given [`ComponentId`]
+    /// is triggered.
+    /// # Safety
+    /// The type of the `event` [`ComponentId`] _must_ match the actual value
+    /// of the event passed into the observer system.
+    pub unsafe fn with_event(mut self, event: ComponentId) -> Self {
+        self.descriptor.events.push(event);
+        self
+    }
+
+    /// Set the error handler to use for this observer.
+    ///
+    /// See the [`error` module-level documentation](crate::error) for more information.
+    pub fn with_error_handler(mut self, error_handler: fn(BevyError, ErrorContext)) -> Self {
+        self.error_handler = Some(error_handler);
+        self
+    }
+
+    /// Returns the [`ObserverDescriptor`] for this [`Observer`].
+    pub fn descriptor(&self) -> &ObserverDescriptor {
+        &self.descriptor
+    }
+
+    /// Returns the name of the [`Observer`]'s system .
+    pub fn system_name(&self) -> DebugName {
+        self.system.system_name()
+    }
+}
+
+impl Component for Observer {
+    const STORAGE_TYPE: StorageType = StorageType::SparseSet;
+    type Mutability = Mutable;
+    fn on_add() -> Option<ComponentHook> {
+        Some(|world, context| {
+            let Some(observe) = world.get::<Self>(context.entity) else {
+                return;
+            };
+            let hook = observe.hook_on_add;
+            hook(world, context);
+        })
+    }
+    fn on_remove() -> Option<ComponentHook> {
+        Some(|mut world, HookContext { entity, .. }| {
+            let descriptor = core::mem::take(
+                &mut world
+                    .entity_mut(entity)
+                    .get_mut::<Self>()
+                    .unwrap()
+                    .as_mut()
+                    .descriptor,
+            );
+            world.commands().queue(move |world: &mut World| {
+                world.unregister_observer(entity, descriptor);
+            });
+        })
+    }
+}
+
+/// Store information about what an [`Observer`] observes.
+///
+/// This information is stored inside of the [`Observer`] component,
+#[derive(Default, Clone)]
+pub struct ObserverDescriptor {
+    /// The events the observer is watching.
+    pub(super) events: Vec<ComponentId>,
+
+    /// The components the observer is watching.
+    pub(super) components: Vec<ComponentId>,
+
+    /// The entities the observer is watching.
+    pub(super) entities: Vec<Entity>,
+}
+
+impl ObserverDescriptor {
+    /// Add the given `events` to the descriptor.
+    /// # Safety
+    /// The type of each [`ComponentId`] in `events` _must_ match the actual value
+    /// of the event passed into the observer.
+    pub unsafe fn with_events(mut self, events: Vec<ComponentId>) -> Self {
+        self.events = events;
+        self
+    }
+
+    /// Add the given `components` to the descriptor.
+    pub fn with_components(mut self, components: Vec<ComponentId>) -> Self {
+        self.components = components;
+        self
+    }
+
+    /// Add the given `entities` to the descriptor.
+    pub fn with_entities(mut self, entities: Vec<Entity>) -> Self {
+        self.entities = entities;
+        self
+    }
+
+    /// Returns the `events` that the observer is watching.
+    pub fn events(&self) -> &[ComponentId] {
+        &self.events
+    }
+
+    /// Returns the `components` that the observer is watching.
+    pub fn components(&self) -> &[ComponentId] {
+        &self.components
+    }
+
+    /// Returns the `entities` that the observer is watching.
+    pub fn entities(&self) -> &[Entity] {
+        &self.entities
+    }
+}
+
+/// A [`ComponentHook`] used by [`Observer`] to handle its [`on-add`](`crate::lifecycle::ComponentHooks::on_add`).
+///
+/// This function exists separate from [`Observer`] to allow [`Observer`] to have its type parameters
+/// erased.
+///
+/// The type parameters of this function _must_ match those used to create the [`Observer`].
+/// As such, it is recommended to only use this function within the [`Observer::new`] method to
+/// ensure type parameters match.
+fn hook_on_add<E: Event, B: Bundle, S: ObserverSystem<E, B>>(
+    mut world: DeferredWorld<'_>,
+    HookContext { entity, .. }: HookContext,
+) {
+    world.commands().queue(move |world: &mut World| {
+        let event_id = E::register_component_id(world);
+        let mut components = alloc::vec![];
+        B::component_ids(&mut world.components_registrator(), &mut |id| {
+            components.push(id);
+        });
+        if let Some(mut observer) = world.get_mut::<Observer>(entity) {
+            observer.descriptor.events.push(event_id);
+            observer.descriptor.components.extend(components);
+
+            let system: &mut dyn Any = observer.system.as_mut();
+            let system: *mut dyn ObserverSystem<E, B> = system.downcast_mut::<S>().unwrap();
+            // SAFETY: World reference is exclusive and initialize does not touch system, so references do not alias
+            unsafe {
+                (*system).initialize(world);
+            }
+            world.register_observer(entity);
+        }
+    });
+}
+
+/// Tracks a list of entity observers for the [`Entity`] [`ObservedBy`] is added to.
+#[derive(Default, Debug)]
+#[cfg_attr(feature = "bevy_reflect", derive(bevy_reflect::Reflect))]
+#[cfg_attr(feature = "bevy_reflect", reflect(Component, Debug))]
+pub struct ObservedBy(pub(crate) Vec<Entity>);
+
+impl ObservedBy {
+    /// Provides a read-only reference to the list of entities observing this entity.
+    pub fn get(&self) -> &[Entity] {
+        &self.0
+    }
+}
+
+impl Component for ObservedBy {
+    const STORAGE_TYPE: StorageType = StorageType::SparseSet;
+    type Mutability = Mutable;
+
+    fn on_remove() -> Option<ComponentHook> {
+        Some(|mut world, HookContext { entity, .. }| {
+            let observed_by = {
+                let mut component = world.get_mut::<ObservedBy>(entity).unwrap();
+                core::mem::take(&mut component.0)
+            };
+            for e in observed_by {
+                let (total_entities, despawned_watched_entities) = {
+                    let Ok(mut entity_mut) = world.get_entity_mut(e) else {
+                        continue;
+                    };
+                    let Some(mut state) = entity_mut.get_mut::<Observer>() else {
+                        continue;
+                    };
+                    state.despawned_watched_entities += 1;
+                    (
+                        state.descriptor.entities.len(),
+                        state.despawned_watched_entities as usize,
+                    )
+                };
+
+                // Despawn Observer if it has no more active sources.
+                if total_entities == despawned_watched_entities {
+                    world.commands().entity(e).despawn();
+                }
+            }
+        })
+    }
+
+    fn clone_behavior() -> ComponentCloneBehavior {
+        ComponentCloneBehavior::Ignore
+    }
+}
+
+pub(crate) trait AnyNamedSystem: Any + Send + Sync + 'static {
+    fn system_name(&self) -> DebugName;
+}
+
+impl<T: Any + System> AnyNamedSystem for T {
+    fn system_name(&self) -> DebugName {
+        self.name()
+    }
+}

crates/bevy_ecs/src/observer/entity_cloning.rs

@@ -1,67 +1,14 @@
+//! Logic to track observers when cloning entities.
+
 use crate::{
-    component::{Component, ComponentCloneBehavior, Mutable, StorageType},
+    component::ComponentCloneBehavior,
-    entity::{ComponentCloneCtx, Entity, EntityClonerBuilder, EntityMapper, SourceComponent},
+    entity::{ComponentCloneCtx, EntityClonerBuilder, EntityMapper, SourceComponent},
-    lifecycle::{ComponentHook, HookContext},
+    observer::ObservedBy,
     world::World,
 };
-use alloc::vec::Vec;
-
-#[cfg(feature = "bevy_reflect")]
-use crate::prelude::ReflectComponent;
 
 use super::Observer;
 
-/// Tracks a list of entity observers for the [`Entity`] [`ObservedBy`] is added to.
-#[derive(Default, Debug)]
-#[cfg_attr(feature = "bevy_reflect", derive(bevy_reflect::Reflect))]
-#[cfg_attr(feature = "bevy_reflect", reflect(Component, Debug))]
-pub struct ObservedBy(pub(crate) Vec<Entity>);
-
-impl ObservedBy {
-    /// Provides a read-only reference to the list of entities observing this entity.
-    pub fn get(&self) -> &[Entity] {
-        &self.0
-    }
-}
-
-impl Component for ObservedBy {
-    const STORAGE_TYPE: StorageType = StorageType::SparseSet;
-    type Mutability = Mutable;
-
-    fn on_remove() -> Option<ComponentHook> {
-        Some(|mut world, HookContext { entity, .. }| {
-            let observed_by = {
-                let mut component = world.get_mut::<ObservedBy>(entity).unwrap();
-                core::mem::take(&mut component.0)
-            };
-            for e in observed_by {
-                let (total_entities, despawned_watched_entities) = {
-                    let Ok(mut entity_mut) = world.get_entity_mut(e) else {
-                        continue;
-                    };
-                    let Some(mut state) = entity_mut.get_mut::<Observer>() else {
-                        continue;
-                    };
-                    state.despawned_watched_entities += 1;
-                    (
-                        state.descriptor.entities.len(),
-                        state.despawned_watched_entities as usize,
-                    )
-                };
-
-                // Despawn Observer if it has no more active sources.
-                if total_entities == despawned_watched_entities {
-                    world.commands().entity(e).despawn();
-                }
-            }
-        })
-    }
-
-    fn clone_behavior() -> ComponentCloneBehavior {
-        ComponentCloneBehavior::Ignore
-    }
-}
-
 impl EntityClonerBuilder<'_> {
     /// Sets the option to automatically add cloned entities to the observers targeting source entity.
     pub fn add_observers(&mut self, add_observers: bool) -> &mut Self {

crates/bevy_ecs/src/observer/mod.rs

@@ -129,614 +129,26 @@
 //! but allows for a more ad hoc approach with observers,
 //! and enables indefinite chaining of observers triggering other observers (for both better and worse!).
 
-mod entity_observer;
+mod centralized_storage;
+mod distributed_storage;
+mod entity_cloning;
 mod runner;
+mod system_param;
+mod trigger_targets;
 
-pub use entity_observer::ObservedBy;
+pub use centralized_storage::*;
+pub use distributed_storage::*;
 pub use runner::*;
-use variadics_please::all_tuples;
+pub use system_param::*;
+pub use trigger_targets::*;
 
 use crate::{
-    archetype::ArchetypeFlags,
     change_detection::MaybeLocation,
     component::ComponentId,
-    entity::EntityHashMap,
     prelude::*,
     system::IntoObserverSystem,
     world::{DeferredWorld, *},
 };
-use alloc::vec::Vec;
-use bevy_platform::collections::HashMap;
-use bevy_ptr::Ptr;
-use core::{
-    fmt::Debug,
-    marker::PhantomData,
-    ops::{Deref, DerefMut},
-};
-use smallvec::SmallVec;
-
-/// Type containing triggered [`Event`] information for a given run of an [`Observer`]. This contains the
-/// [`Event`] data itself. If it was triggered for a specific [`Entity`], it includes that as well. It also
-/// contains event propagation information. See [`On::propagate`] for more information.
-///
-/// The generic `B: Bundle` is used to modify the further specialize the events that this observer is interested in.
-/// The entity involved *does not* have to have these components, but the observer will only be
-/// triggered if the event matches the components in `B`.
-///
-/// This is used to to avoid providing a generic argument in your event, as is done for [`Add`]
-/// and the other lifecycle events.
-///
-/// Providing multiple components in this bundle will cause this event to be triggered by any
-/// matching component in the bundle,
-/// [rather than requiring all of them to be present](https://github.com/bevyengine/bevy/issues/15325).
-pub struct On<'w, E, B: Bundle = ()> {
-    event: &'w mut E,
-    propagate: &'w mut bool,
-    trigger: ObserverTrigger,
-    _marker: PhantomData<B>,
-}
-
-/// Deprecated in favor of [`On`].
-#[deprecated(since = "0.17.0", note = "Renamed to `On`.")]
-pub type Trigger<'w, E, B = ()> = On<'w, E, B>;
-
-impl<'w, E, B: Bundle> On<'w, E, B> {
-    /// Creates a new instance of [`On`] for the given event and observer information.
-    pub fn new(event: &'w mut E, propagate: &'w mut bool, trigger: ObserverTrigger) -> Self {
-        Self {
-            event,
-            propagate,
-            trigger,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Returns the event type of this [`On`] instance.
-    pub fn event_type(&self) -> ComponentId {
-        self.trigger.event_type
-    }
-
-    /// Returns a reference to the triggered event.
-    pub fn event(&self) -> &E {
-        self.event
-    }
-
-    /// Returns a mutable reference to the triggered event.
-    pub fn event_mut(&mut self) -> &mut E {
-        self.event
-    }
-
-    /// Returns a pointer to the triggered event.
-    pub fn event_ptr(&self) -> Ptr {
-        Ptr::from(&self.event)
-    }
-
-    /// Returns the components that triggered the observer, out of the
-    /// components defined in `B`. Does not necessarily include all of them as
-    /// `B` acts like an `OR` filter rather than an `AND` filter.
-    pub fn components(&self) -> &[ComponentId] {
-        &self.trigger.components
-    }
-
-    /// Returns the [`Entity`] that observed the triggered event.
-    /// This allows you to despawn the observer, ceasing observation.
-    ///
-    /// # Examples
-    ///
-    /// ```rust
-    /// # use bevy_ecs::prelude::{Commands, On};
-    /// #
-    /// # struct MyEvent {
-    /// #   done: bool,
-    /// # }
-    /// #
-    /// /// Handle `MyEvent` and if it is done, stop observation.
-    /// fn my_observer(trigger: On<MyEvent>, mut commands: Commands) {
-    ///     if trigger.event().done {
-    ///         commands.entity(trigger.observer()).despawn();
-    ///         return;
-    ///     }
-    ///
-    ///     // ...
-    /// }
-    /// ```
-    pub fn observer(&self) -> Entity {
-        self.trigger.observer
-    }
-
-    /// Returns the source code location that triggered this observer.
-    pub fn caller(&self) -> MaybeLocation {
-        self.trigger.caller
-    }
-}
-
-impl<'w, E: EntityEvent, B: Bundle> On<'w, E, B> {
-    /// Returns the [`Entity`] that was targeted by the `event` that triggered this observer.
-    ///
-    /// Note that if event propagation is enabled, this may not be the same as the original target of the event,
-    /// which can be accessed via [`On::original_target`].
-    ///
-    /// If the event was not targeted at a specific entity, this will return [`Entity::PLACEHOLDER`].
-    pub fn target(&self) -> Entity {
-        self.trigger.current_target.unwrap_or(Entity::PLACEHOLDER)
-    }
-
-    /// Returns the original [`Entity`] that the `event` was targeted at when it was first triggered.
-    ///
-    /// If event propagation is not enabled, this will always return the same value as [`On::target`].
-    ///
-    /// If the event was not targeted at a specific entity, this will return [`Entity::PLACEHOLDER`].
-    pub fn original_target(&self) -> Entity {
-        self.trigger.original_target.unwrap_or(Entity::PLACEHOLDER)
-    }
-
-    /// Enables or disables event propagation, allowing the same event to trigger observers on a chain of different entities.
-    ///
-    /// The path an event will propagate along is specified by its associated [`Traversal`] component. By default, events
-    /// use `()` which ends the path immediately and prevents propagation.
-    ///
-    /// To enable propagation, you must:
-    /// + Set [`EntityEvent::Traversal`] to the component you want to propagate along.
-    /// + Either call `propagate(true)` in the first observer or set [`EntityEvent::AUTO_PROPAGATE`] to `true`.
-    ///
-    /// You can prevent an event from propagating further using `propagate(false)`.
-    ///
-    /// [`Traversal`]: crate::traversal::Traversal
-    pub fn propagate(&mut self, should_propagate: bool) {
-        *self.propagate = should_propagate;
-    }
-
-    /// Returns the value of the flag that controls event propagation. See [`propagate`] for more information.
-    ///
-    /// [`propagate`]: On::propagate
-    pub fn get_propagate(&self) -> bool {
-        *self.propagate
-    }
-}
-
-impl<'w, E: Debug, B: Bundle> Debug for On<'w, E, B> {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        f.debug_struct("On")
-            .field("event", &self.event)
-            .field("propagate", &self.propagate)
-            .field("trigger", &self.trigger)
-            .field("_marker", &self._marker)
-            .finish()
-    }
-}
-
-impl<'w, E, B: Bundle> Deref for On<'w, E, B> {
-    type Target = E;
-
-    fn deref(&self) -> &Self::Target {
-        self.event
-    }
-}
-
-impl<'w, E, B: Bundle> DerefMut for On<'w, E, B> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        self.event
-    }
-}
-
-/// Represents a collection of targets for a specific [`On`] instance of an [`Event`].
-///
-/// When an event is triggered with [`TriggerTargets`], any [`Observer`] that watches for that specific
-/// event-target combination will run.
-///
-/// This trait is implemented for both [`Entity`] and [`ComponentId`], allowing you to target specific entities or components.
-/// It is also implemented for various collections of these types, such as [`Vec`], arrays, and tuples,
-/// allowing you to trigger events for multiple targets at once.
-pub trait TriggerTargets {
-    /// The components the trigger should target.
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_;
-
-    /// The entities the trigger should target.
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_;
-}
-
-impl<T: TriggerTargets + ?Sized> TriggerTargets for &T {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        (**self).components()
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        (**self).entities()
-    }
-}
-
-impl TriggerTargets for Entity {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        [].into_iter()
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        core::iter::once(*self)
-    }
-}
-
-impl TriggerTargets for ComponentId {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        core::iter::once(*self)
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        [].into_iter()
-    }
-}
-
-impl<T: TriggerTargets> TriggerTargets for Vec<T> {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        self.iter().flat_map(T::components)
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        self.iter().flat_map(T::entities)
-    }
-}
-
-impl<const N: usize, T: TriggerTargets> TriggerTargets for [T; N] {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        self.iter().flat_map(T::components)
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        self.iter().flat_map(T::entities)
-    }
-}
-
-impl<T: TriggerTargets> TriggerTargets for [T] {
-    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-        self.iter().flat_map(T::components)
-    }
-
-    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-        self.iter().flat_map(T::entities)
-    }
-}
-
-macro_rules! impl_trigger_targets_tuples {
-    ($(#[$meta:meta])* $($trigger_targets: ident),*) => {
-        #[expect(clippy::allow_attributes, reason = "can't guarantee violation of non_snake_case")]
-        #[allow(non_snake_case, reason = "`all_tuples!()` generates non-snake-case variable names.")]
-        $(#[$meta])*
-        impl<$($trigger_targets: TriggerTargets),*> TriggerTargets for ($($trigger_targets,)*)
-        {
-            fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
-                let iter = [].into_iter();
-                let ($($trigger_targets,)*) = self;
-                $(
-                    let iter = iter.chain($trigger_targets.components());
-                )*
-                iter
-            }
-
-            fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
-                let iter = [].into_iter();
-                let ($($trigger_targets,)*) = self;
-                $(
-                    let iter = iter.chain($trigger_targets.entities());
-                )*
-                iter
-            }
-        }
-    }
-}
-
-all_tuples!(
-    #[doc(fake_variadic)]
-    impl_trigger_targets_tuples,
-    0,
-    15,
-    T
-);
-
-/// Store information about what an [`Observer`] observes.
-///
-/// This information is stored inside of the [`Observer`] component,
-#[derive(Default, Clone)]
-pub struct ObserverDescriptor {
-    /// The events the observer is watching.
-    events: Vec<ComponentId>,
-
-    /// The components the observer is watching.
-    components: Vec<ComponentId>,
-
-    /// The entities the observer is watching.
-    entities: Vec<Entity>,
-}
-
-impl ObserverDescriptor {
-    /// Add the given `events` to the descriptor.
-    /// # Safety
-    /// The type of each [`ComponentId`] in `events` _must_ match the actual value
-    /// of the event passed into the observer.
-    pub unsafe fn with_events(mut self, events: Vec<ComponentId>) -> Self {
-        self.events = events;
-        self
-    }
-
-    /// Add the given `components` to the descriptor.
-    pub fn with_components(mut self, components: Vec<ComponentId>) -> Self {
-        self.components = components;
-        self
-    }
-
-    /// Add the given `entities` to the descriptor.
-    pub fn with_entities(mut self, entities: Vec<Entity>) -> Self {
-        self.entities = entities;
-        self
-    }
-
-    /// Returns the `events` that the observer is watching.
-    pub fn events(&self) -> &[ComponentId] {
-        &self.events
-    }
-
-    /// Returns the `components` that the observer is watching.
-    pub fn components(&self) -> &[ComponentId] {
-        &self.components
-    }
-
-    /// Returns the `entities` that the observer is watching.
-    pub fn entities(&self) -> &[Entity] {
-        &self.entities
-    }
-}
-
-/// Metadata about a specific [`Event`] that triggered an observer.
-///
-/// This information is exposed via methods on [`On`].
-#[derive(Debug)]
-pub struct ObserverTrigger {
-    /// The [`Entity`] of the observer handling the trigger.
-    pub observer: Entity,
-    /// The [`Event`] the trigger targeted.
-    pub event_type: ComponentId,
-    /// The [`ComponentId`]s the trigger targeted.
-    components: SmallVec<[ComponentId; 2]>,
-    /// The entity that the entity-event targeted, if any.
-    ///
-    /// Note that if event propagation is enabled, this may not be the same as [`ObserverTrigger::original_target`].
-    pub current_target: Option<Entity>,
-    /// The entity that the entity-event was originally targeted at, if any.
-    ///
-    /// If event propagation is enabled, this will be the first entity that the event was targeted at,
-    /// even if the event was propagated to other entities.
-    pub original_target: Option<Entity>,
-    /// The location of the source code that triggered the observer.
-    pub caller: MaybeLocation,
-}
-
-impl ObserverTrigger {
-    /// Returns the components that the trigger targeted.
-    pub fn components(&self) -> &[ComponentId] {
-        &self.components
-    }
-}
-
-/// Map between an observer entity and its [`ObserverRunner`]
-pub type ObserverMap = EntityHashMap<ObserverRunner>;
-
-/// Collection of [`ObserverRunner`] for [`Observer`] registered to a particular event targeted at a specific component.
-///
-/// This is stored inside of [`CachedObservers`].
-#[derive(Default, Debug)]
-pub struct CachedComponentObservers {
-    // Observers listening to events targeting this component, but not a specific entity
-    global_observers: ObserverMap,
-    // Observers listening to events targeting this component on a specific entity
-    entity_component_observers: EntityHashMap<ObserverMap>,
-}
-
-impl CachedComponentObservers {
-    /// Returns the observers listening for this trigger, regardless of target.
-    /// These observers will also respond to events targeting specific entities.
-    pub fn global_observers(&self) -> &ObserverMap {
-        &self.global_observers
-    }
-
-    /// Returns the observers listening for this trigger targeting this component on a specific entity.
-    pub fn entity_component_observers(&self) -> &EntityHashMap<ObserverMap> {
-        &self.entity_component_observers
-    }
-}
-
-/// Collection of [`ObserverRunner`] for [`Observer`] registered to a particular event.
-///
-/// This is stored inside of [`Observers`], specialized for each kind of observer.
-#[derive(Default, Debug)]
-pub struct CachedObservers {
-    // Observers listening for any time this event is fired, regardless of target
-    // This will also respond to events targeting specific components or entities
-    global_observers: ObserverMap,
-    // Observers listening for this trigger fired at a specific component
-    component_observers: HashMap<ComponentId, CachedComponentObservers>,
-    // Observers listening for this trigger fired at a specific entity
-    entity_observers: EntityHashMap<ObserverMap>,
-}
-
-impl CachedObservers {
-    /// Returns the observers listening for this trigger, regardless of target.
-    /// These observers will also respond to events targeting specific components or entities.
-    pub fn global_observers(&self) -> &ObserverMap {
-        &self.global_observers
-    }
-
-    /// Returns the observers listening for this trigger targeting components.
-    pub fn get_component_observers(&self) -> &HashMap<ComponentId, CachedComponentObservers> {
-        &self.component_observers
-    }
-
-    /// Returns the observers listening for this trigger targeting entities.
-    pub fn entity_observers(&self) -> &HashMap<ComponentId, CachedComponentObservers> {
-        &self.component_observers
-    }
-}
-
-/// An internal lookup table tracking all of the observers in the world.
-///
-/// Stores a cache mapping trigger ids to the registered observers.
-/// Some observer kinds (like [lifecycle](crate::lifecycle) observers) have a dedicated field,
-/// saving lookups for the most common triggers.
-///
-/// This can be accessed via [`World::observers`].
-#[derive(Default, Debug)]
-pub struct Observers {
-    // Cached ECS observers to save a lookup most common triggers.
-    add: CachedObservers,
-    insert: CachedObservers,
-    replace: CachedObservers,
-    remove: CachedObservers,
-    despawn: CachedObservers,
-    // Map from trigger type to set of observers listening to that trigger
-    cache: HashMap<ComponentId, CachedObservers>,
-}
-
-impl Observers {
-    pub(crate) fn get_observers_mut(&mut self, event_type: ComponentId) -> &mut CachedObservers {
-        use crate::lifecycle::*;
-
-        match event_type {
-            ADD => &mut self.add,
-            INSERT => &mut self.insert,
-            REPLACE => &mut self.replace,
-            REMOVE => &mut self.remove,
-            DESPAWN => &mut self.despawn,
-            _ => self.cache.entry(event_type).or_default(),
-        }
-    }
-
-    /// Attempts to get the observers for the given `event_type`.
-    ///
-    /// When accessing the observers for lifecycle events, such as [`Add`], [`Insert`], [`Replace`], [`Remove`], and [`Despawn`],
-    /// use the [`ComponentId`] constants from the [`lifecycle`](crate::lifecycle) module.
-    pub fn try_get_observers(&self, event_type: ComponentId) -> Option<&CachedObservers> {
-        use crate::lifecycle::*;
-
-        match event_type {
-            ADD => Some(&self.add),
-            INSERT => Some(&self.insert),
-            REPLACE => Some(&self.replace),
-            REMOVE => Some(&self.remove),
-            DESPAWN => Some(&self.despawn),
-            _ => self.cache.get(&event_type),
-        }
-    }
-
-    /// This will run the observers of the given `event_type`, targeting the given `entity` and `components`.
-    pub(crate) fn invoke<T>(
-        mut world: DeferredWorld,
-        event_type: ComponentId,
-        current_target: Option<Entity>,
-        original_target: Option<Entity>,
-        components: impl Iterator<Item = ComponentId> + Clone,
-        data: &mut T,
-        propagate: &mut bool,
-        caller: MaybeLocation,
-    ) {
-        // SAFETY: You cannot get a mutable reference to `observers` from `DeferredWorld`
-        let (mut world, observers) = unsafe {
-            let world = world.as_unsafe_world_cell();
-            // SAFETY: There are no outstanding world references
-            world.increment_trigger_id();
-            let observers = world.observers();
-            let Some(observers) = observers.try_get_observers(event_type) else {
-                return;
-            };
-            // SAFETY: The only outstanding reference to world is `observers`
-            (world.into_deferred(), observers)
-        };
-
-        let trigger_for_components = components.clone();
-
-        let mut trigger_observer = |(&observer, runner): (&Entity, &ObserverRunner)| {
-            (runner)(
-                world.reborrow(),
-                ObserverTrigger {
-                    observer,
-                    event_type,
-                    components: components.clone().collect(),
-                    current_target,
-                    original_target,
-                    caller,
-                },
-                data.into(),
-                propagate,
-            );
-        };
-        // Trigger observers listening for any kind of this trigger
-        observers
-            .global_observers
-            .iter()
-            .for_each(&mut trigger_observer);
-
-        // Trigger entity observers listening for this kind of trigger
-        if let Some(target_entity) = current_target {
-            if let Some(map) = observers.entity_observers.get(&target_entity) {
-                map.iter().for_each(&mut trigger_observer);
-            }
-        }
-
-        // Trigger observers listening to this trigger targeting a specific component
-        trigger_for_components.for_each(|id| {
-            if let Some(component_observers) = observers.component_observers.get(&id) {
-                component_observers
-                    .global_observers
-                    .iter()
-                    .for_each(&mut trigger_observer);
-
-                if let Some(target_entity) = current_target {
-                    if let Some(map) = component_observers
-                        .entity_component_observers
-                        .get(&target_entity)
-                    {
-                        map.iter().for_each(&mut trigger_observer);
-                    }
-                }
-            }
-        });
-    }
-
-    pub(crate) fn is_archetype_cached(event_type: ComponentId) -> Option<ArchetypeFlags> {
-        use crate::lifecycle::*;
-
-        match event_type {
-            ADD => Some(ArchetypeFlags::ON_ADD_OBSERVER),
-            INSERT => Some(ArchetypeFlags::ON_INSERT_OBSERVER),
-            REPLACE => Some(ArchetypeFlags::ON_REPLACE_OBSERVER),
-            REMOVE => Some(ArchetypeFlags::ON_REMOVE_OBSERVER),
-            DESPAWN => Some(ArchetypeFlags::ON_DESPAWN_OBSERVER),
-            _ => None,
-        }
-    }
-
-    pub(crate) fn update_archetype_flags(
-        &self,
-        component_id: ComponentId,
-        flags: &mut ArchetypeFlags,
-    ) {
-        if self.add.component_observers.contains_key(&component_id) {
-            flags.insert(ArchetypeFlags::ON_ADD_OBSERVER);
-        }
-
-        if self.insert.component_observers.contains_key(&component_id) {
-            flags.insert(ArchetypeFlags::ON_INSERT_OBSERVER);
-        }
-
-        if self.replace.component_observers.contains_key(&component_id) {
-            flags.insert(ArchetypeFlags::ON_REPLACE_OBSERVER);
-        }
-
-        if self.remove.component_observers.contains_key(&component_id) {
-            flags.insert(ArchetypeFlags::ON_REMOVE_OBSERVER);
-        }
-
-        if self.despawn.component_observers.contains_key(&component_id) {
-            flags.insert(ArchetypeFlags::ON_DESPAWN_OBSERVER);
-        }
-    }
-}
 
 impl World {
     /// Spawns a "global" [`Observer`] which will watch for the given event.
@@ -1315,7 +727,7 @@ mod tests {
         world.spawn(A).flush();
         assert_eq!(vec!["add_2", "add_1"], world.resource::<Order>().0);
         // Our A entity plus our two observers
-        assert_eq!(world.entities().count_constructed(), 3);
+        assert_eq!(world.entity_count(), 3);
     }
 
     #[test]

crates/bevy_ecs/src/observer/runner.rs

@@ -1,16 +1,10 @@
-use alloc::{boxed::Box, vec};
+//! Logic for evaluating observers, and storing functions inside of observers.
-use bevy_utils::prelude::DebugName;
+
 use core::any::Any;
 
 use crate::{
-    component::{ComponentId, Mutable, StorageType},
+    error::ErrorContext, observer::ObserverTrigger, prelude::*, query::DebugCheckedUnwrap,
-    error::{ErrorContext, ErrorHandler},
+    system::ObserverSystem, world::DeferredWorld,
-    lifecycle::{ComponentHook, HookContext},
-    observer::{ObserverDescriptor, ObserverTrigger},
-    prelude::*,
-    query::DebugCheckedUnwrap,
-    system::{IntoObserverSystem, ObserverSystem},
-    world::DeferredWorld,
 };
 use bevy_ptr::PtrMut;
 
@@ -20,323 +14,7 @@ use bevy_ptr::PtrMut;
 /// but can be overridden for custom behavior.
 pub type ObserverRunner = fn(DeferredWorld, ObserverTrigger, PtrMut, propagate: &mut bool);
 
-/// An [`Observer`] system. Add this [`Component`] to an [`Entity`] to turn it into an "observer".
+pub(super) fn observer_system_runner<E: Event, B: Bundle, S: ObserverSystem<E, B>>(
-///
-/// Observers listen for a "trigger" of a specific [`Event`]. An event can be triggered on the [`World`]
-/// by calling [`World::trigger`], or if the event is an [`EntityEvent`], it can also be triggered for specific
-/// entity targets using [`World::trigger_targets`].
-///
-/// Note that [`BufferedEvent`]s sent using [`EventReader`] and [`EventWriter`] are _not_ automatically triggered.
-/// They must be triggered at a specific point in the schedule.
-///
-/// # Usage
-///
-/// The simplest usage of the observer pattern looks like this:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// #[derive(Event)]
-/// struct Speak {
-///     message: String,
-/// }
-///
-/// world.add_observer(|trigger: On<Speak>| {
-///     println!("{}", trigger.event().message);
-/// });
-///
-/// // Observers currently require a flush() to be registered. In the context of schedules,
-/// // this will generally be done for you.
-/// world.flush();
-///
-/// world.trigger(Speak {
-///     message: "Hello!".into(),
-/// });
-/// ```
-///
-/// Notice that we used [`World::add_observer`]. This is just a shorthand for spawning an [`Observer`] manually:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # #[derive(Event)]
-/// # struct Speak;
-/// // These are functionally the same:
-/// world.add_observer(|trigger: On<Speak>| {});
-/// world.spawn(Observer::new(|trigger: On<Speak>| {}));
-/// ```
-///
-/// Observers are systems. They can access arbitrary [`World`] data by adding [`SystemParam`]s:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # #[derive(Event)]
-/// # struct PrintNames;
-/// # #[derive(Component, Debug)]
-/// # struct Name;
-/// world.add_observer(|trigger: On<PrintNames>, names: Query<&Name>| {
-///     for name in &names {
-///         println!("{name:?}");
-///     }
-/// });
-/// ```
-///
-/// Note that [`On`] must always be the first parameter.
-///
-/// You can also add [`Commands`], which means you can spawn new entities, insert new components, etc:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # #[derive(Event)]
-/// # struct SpawnThing;
-/// # #[derive(Component, Debug)]
-/// # struct Thing;
-/// world.add_observer(|trigger: On<SpawnThing>, mut commands: Commands| {
-///     commands.spawn(Thing);
-/// });
-/// ```
-///
-/// Observers can also trigger new events:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # #[derive(Event)]
-/// # struct A;
-/// # #[derive(Event)]
-/// # struct B;
-/// world.add_observer(|trigger: On<A>, mut commands: Commands| {
-///     commands.trigger(B);
-/// });
-/// ```
-///
-/// When the commands are flushed (including these "nested triggers") they will be
-/// recursively evaluated until there are no commands left, meaning nested triggers all
-/// evaluate at the same time!
-///
-/// If the event is an [`EntityEvent`], it can be triggered for specific entities,
-/// which will be passed to the [`Observer`]:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # let entity = world.spawn_empty().id();
-/// #[derive(Event, EntityEvent)]
-/// struct Explode;
-///
-/// world.add_observer(|trigger: On<Explode>, mut commands: Commands| {
-///     println!("Entity {} goes BOOM!", trigger.target());
-///     commands.entity(trigger.target()).despawn();
-/// });
-///
-/// world.flush();
-///
-/// world.trigger_targets(Explode, entity);
-/// ```
-///
-/// You can trigger multiple entities at once:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # let e1 = world.spawn_empty().id();
-/// # let e2 = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
-/// # struct Explode;
-/// world.trigger_targets(Explode, [e1, e2]);
-/// ```
-///
-/// Observers can also watch _specific_ entities, which enables you to assign entity-specific logic:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # #[derive(Component, Debug)]
-/// # struct Name(String);
-/// # let mut world = World::default();
-/// # let e1 = world.spawn_empty().id();
-/// # let e2 = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
-/// # struct Explode;
-/// world.entity_mut(e1).observe(|trigger: On<Explode>, mut commands: Commands| {
-///     println!("Boom!");
-///     commands.entity(trigger.target()).despawn();
-/// });
-///
-/// world.entity_mut(e2).observe(|trigger: On<Explode>, mut commands: Commands| {
-///     println!("The explosion fizzles! This entity is immune!");
-/// });
-/// ```
-///
-/// If all entities watched by a given [`Observer`] are despawned, the [`Observer`] entity will also be despawned.
-/// This protects against observer "garbage" building up over time.
-///
-/// The examples above calling [`EntityWorldMut::observe`] to add entity-specific observer logic are (once again)
-/// just shorthand for spawning an [`Observer`] directly:
-///
-/// ```
-/// # use bevy_ecs::prelude::*;
-/// # let mut world = World::default();
-/// # let entity = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
-/// # struct Explode;
-/// let mut observer = Observer::new(|trigger: On<Explode>| {});
-/// observer.watch_entity(entity);
-/// world.spawn(observer);
-/// ```
-///
-/// Note that the [`Observer`] component is not added to the entity it is observing. Observers should always be their own entities!
-///
-/// You can call [`Observer::watch_entity`] more than once, which allows you to watch multiple entities with the same [`Observer`].
-/// serves as the "source of truth" of the observer.
-///
-/// [`SystemParam`]: crate::system::SystemParam
-pub struct Observer {
-    hook_on_add: ComponentHook,
-    error_handler: Option<ErrorHandler>,
-    system: Box<dyn AnyNamedSystem>,
-    pub(crate) descriptor: ObserverDescriptor,
-    pub(crate) last_trigger_id: u32,
-    pub(crate) despawned_watched_entities: u32,
-    pub(crate) runner: ObserverRunner,
-}
-
-impl Observer {
-    /// Creates a new [`Observer`], which defaults to a "global" observer. This means it will run whenever the event `E` is triggered
-    /// for _any_ entity (or no entity).
-    ///
-    /// # Panics
-    ///
-    /// Panics if the given system is an exclusive system.
-    pub fn new<E: Event, B: Bundle, M, I: IntoObserverSystem<E, B, M>>(system: I) -> Self {
-        let system = Box::new(IntoObserverSystem::into_system(system));
-        assert!(
-            !system.is_exclusive(),
-            concat!(
-                "Exclusive system `{}` may not be used as observer.\n",
-                "Instead of `&mut World`, use either `DeferredWorld` if you do not need structural changes, or `Commands` if you do."
-            ),
-            system.name()
-        );
-        Self {
-            system,
-            descriptor: Default::default(),
-            hook_on_add: hook_on_add::<E, B, I::System>,
-            error_handler: None,
-            runner: observer_system_runner::<E, B, I::System>,
-            despawned_watched_entities: 0,
-            last_trigger_id: 0,
-        }
-    }
-
-    /// Creates a new [`Observer`] with custom runner, this is mostly used for dynamic event observer
-    pub fn with_dynamic_runner(runner: ObserverRunner) -> Self {
-        Self {
-            system: Box::new(IntoSystem::into_system(|| {})),
-            descriptor: Default::default(),
-            hook_on_add: |mut world, hook_context| {
-                let default_error_handler = world.default_error_handler();
-                world.commands().queue(move |world: &mut World| {
-                    let entity = hook_context.entity;
-                    if let Some(mut observe) = world.get_mut::<Observer>(entity) {
-                        if observe.descriptor.events.is_empty() {
-                            return;
-                        }
-                        if observe.error_handler.is_none() {
-                            observe.error_handler = Some(default_error_handler);
-                        }
-                        world.register_observer(entity);
-                    }
-                });
-            },
-            error_handler: None,
-            runner,
-            despawned_watched_entities: 0,
-            last_trigger_id: 0,
-        }
-    }
-
-    /// Observe the given `entity`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
-    /// for the `entity`.
-    pub fn with_entity(mut self, entity: Entity) -> Self {
-        self.descriptor.entities.push(entity);
-        self
-    }
-
-    /// Observe the given `entity`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
-    /// for the `entity`.
-    /// Note that if this is called _after_ an [`Observer`] is spawned, it will produce no effects.
-    pub fn watch_entity(&mut self, entity: Entity) {
-        self.descriptor.entities.push(entity);
-    }
-
-    /// Observe the given `component`. This will cause the [`Observer`] to run whenever the [`Event`] is triggered
-    /// with the given component target.
-    pub fn with_component(mut self, component: ComponentId) -> Self {
-        self.descriptor.components.push(component);
-        self
-    }
-
-    /// Observe the given `event`. This will cause the [`Observer`] to run whenever an event with the given [`ComponentId`]
-    /// is triggered.
-    /// # Safety
-    /// The type of the `event` [`ComponentId`] _must_ match the actual value
-    /// of the event passed into the observer system.
-    pub unsafe fn with_event(mut self, event: ComponentId) -> Self {
-        self.descriptor.events.push(event);
-        self
-    }
-
-    /// Set the error handler to use for this observer.
-    ///
-    /// See the [`error` module-level documentation](crate::error) for more information.
-    pub fn with_error_handler(mut self, error_handler: fn(BevyError, ErrorContext)) -> Self {
-        self.error_handler = Some(error_handler);
-        self
-    }
-
-    /// Returns the [`ObserverDescriptor`] for this [`Observer`].
-    pub fn descriptor(&self) -> &ObserverDescriptor {
-        &self.descriptor
-    }
-
-    /// Returns the name of the [`Observer`]'s system .
-    pub fn system_name(&self) -> DebugName {
-        self.system.system_name()
-    }
-}
-
-impl Component for Observer {
-    const STORAGE_TYPE: StorageType = StorageType::SparseSet;
-    type Mutability = Mutable;
-    fn on_add() -> Option<ComponentHook> {
-        Some(|world, context| {
-            let Some(observe) = world.get::<Self>(context.entity) else {
-                return;
-            };
-            let hook = observe.hook_on_add;
-            hook(world, context);
-        })
-    }
-    fn on_remove() -> Option<ComponentHook> {
-        Some(|mut world, HookContext { entity, .. }| {
-            let descriptor = core::mem::take(
-                &mut world
-                    .entity_mut(entity)
-                    .get_mut::<Self>()
-                    .unwrap()
-                    .as_mut()
-                    .descriptor,
-            );
-            world.commands().queue(move |world: &mut World| {
-                world.unregister_observer(entity, descriptor);
-            });
-        })
-    }
-}
-
-fn observer_system_runner<E: Event, B: Bundle, S: ObserverSystem<E, B>>(
     mut world: DeferredWorld,
     observer_trigger: ObserverTrigger,
     ptr: PtrMut,
@@ -420,48 +98,6 @@ fn observer_system_runner<E: Event, B: Bundle, S: ObserverSystem<E, B>>(
     }
 }
 
-trait AnyNamedSystem: Any + Send + Sync + 'static {
-    fn system_name(&self) -> DebugName;
-}
-
-impl<T: Any + System> AnyNamedSystem for T {
-    fn system_name(&self) -> DebugName {
-        self.name()
-    }
-}
-
-/// A [`ComponentHook`] used by [`Observer`] to handle its [`on-add`](`crate::lifecycle::ComponentHooks::on_add`).
-///
-/// This function exists separate from [`Observer`] to allow [`Observer`] to have its type parameters
-/// erased.
-///
-/// The type parameters of this function _must_ match those used to create the [`Observer`].
-/// As such, it is recommended to only use this function within the [`Observer::new`] method to
-/// ensure type parameters match.
-fn hook_on_add<E: Event, B: Bundle, S: ObserverSystem<E, B>>(
-    mut world: DeferredWorld<'_>,
-    HookContext { entity, .. }: HookContext,
-) {
-    world.commands().queue(move |world: &mut World| {
-        let event_id = E::register_component_id(world);
-        let mut components = vec![];
-        B::component_ids(&mut world.components_registrator(), &mut |id| {
-            components.push(id);
-        });
-        if let Some(mut observer) = world.get_mut::<Observer>(entity) {
-            observer.descriptor.events.push(event_id);
-            observer.descriptor.components.extend(components);
-
-            let system: &mut dyn Any = observer.system.as_mut();
-            let system: *mut dyn ObserverSystem<E, B> = system.downcast_mut::<S>().unwrap();
-            // SAFETY: World reference is exclusive and initialize does not touch system, so references do not alias
-            unsafe {
-                (*system).initialize(world);
-            }
-            world.register_observer(entity);
-        }
-    });
-}
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -516,9 +152,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Exclusive system `bevy_ecs::observer::runner::tests::exclusive_system_cannot_be_observer::system` may not be used as observer.\nInstead of `&mut World`, use either `DeferredWorld` if you do not need structural changes, or `Commands` if you do."
-    )]
     fn exclusive_system_cannot_be_observer() {
         fn system(_: On<TriggerEvent>, _world: &mut World) {}
         let mut world = World::default();

crates/bevy_ecs/src/observer/system_param.rs

@@ -0,0 +1,206 @@
+//! System parameters for working with observers.
+
+use core::marker::PhantomData;
+use core::ops::DerefMut;
+use core::{fmt::Debug, ops::Deref};
+
+use bevy_ptr::Ptr;
+use smallvec::SmallVec;
+
+use crate::{
+    bundle::Bundle, change_detection::MaybeLocation, component::ComponentId, event::EntityEvent,
+    prelude::*,
+};
+
+/// Type containing triggered [`Event`] information for a given run of an [`Observer`]. This contains the
+/// [`Event`] data itself. If it was triggered for a specific [`Entity`], it includes that as well. It also
+/// contains event propagation information. See [`On::propagate`] for more information.
+///
+/// The generic `B: Bundle` is used to modify the further specialize the events that this observer is interested in.
+/// The entity involved *does not* have to have these components, but the observer will only be
+/// triggered if the event matches the components in `B`.
+///
+/// This is used to to avoid providing a generic argument in your event, as is done for [`Add`]
+/// and the other lifecycle events.
+///
+/// Providing multiple components in this bundle will cause this event to be triggered by any
+/// matching component in the bundle,
+/// [rather than requiring all of them to be present](https://github.com/bevyengine/bevy/issues/15325).
+pub struct On<'w, E, B: Bundle = ()> {
+    event: &'w mut E,
+    propagate: &'w mut bool,
+    trigger: ObserverTrigger,
+    _marker: PhantomData<B>,
+}
+
+/// Deprecated in favor of [`On`].
+#[deprecated(since = "0.17.0", note = "Renamed to `On`.")]
+pub type Trigger<'w, E, B = ()> = On<'w, E, B>;
+
+impl<'w, E, B: Bundle> On<'w, E, B> {
+    /// Creates a new instance of [`On`] for the given event and observer information.
+    pub fn new(event: &'w mut E, propagate: &'w mut bool, trigger: ObserverTrigger) -> Self {
+        Self {
+            event,
+            propagate,
+            trigger,
+            _marker: PhantomData,
+        }
+    }
+
+    /// Returns the event type of this [`On`] instance.
+    pub fn event_type(&self) -> ComponentId {
+        self.trigger.event_type
+    }
+
+    /// Returns a reference to the triggered event.
+    pub fn event(&self) -> &E {
+        self.event
+    }
+
+    /// Returns a mutable reference to the triggered event.
+    pub fn event_mut(&mut self) -> &mut E {
+        self.event
+    }
+
+    /// Returns a pointer to the triggered event.
+    pub fn event_ptr(&self) -> Ptr {
+        Ptr::from(&self.event)
+    }
+
+    /// Returns the components that triggered the observer, out of the
+    /// components defined in `B`. Does not necessarily include all of them as
+    /// `B` acts like an `OR` filter rather than an `AND` filter.
+    pub fn components(&self) -> &[ComponentId] {
+        &self.trigger.components
+    }
+
+    /// Returns the [`Entity`] that observed the triggered event.
+    /// This allows you to despawn the observer, ceasing observation.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use bevy_ecs::prelude::*;
+    ///
+    /// #[derive(Event, EntityEvent)]  
+    /// struct AssertEvent;  
+    ///
+    /// fn assert_observer(trigger: On<AssertEvent>) {  
+    ///     assert_eq!(trigger.observer(), trigger.target());  
+    /// }  
+    ///
+    /// let mut world = World::new();  
+    /// let observer = world.spawn(Observer::new(assert_observer)).id();  
+    ///
+    /// world.trigger_targets(AssertEvent, observer);  
+    /// ```
+    pub fn observer(&self) -> Entity {
+        self.trigger.observer
+    }
+
+    /// Returns the source code location that triggered this observer.
+    pub fn caller(&self) -> MaybeLocation {
+        self.trigger.caller
+    }
+}
+
+impl<'w, E: EntityEvent, B: Bundle> On<'w, E, B> {
+    /// Returns the [`Entity`] that was targeted by the `event` that triggered this observer.
+    ///
+    /// Note that if event propagation is enabled, this may not be the same as the original target of the event,
+    /// which can be accessed via [`On::original_target`].
+    ///
+    /// If the event was not targeted at a specific entity, this will return [`Entity::PLACEHOLDER`].
+    pub fn target(&self) -> Entity {
+        self.trigger.current_target.unwrap_or(Entity::PLACEHOLDER)
+    }
+
+    /// Returns the original [`Entity`] that the `event` was targeted at when it was first triggered.
+    ///
+    /// If event propagation is not enabled, this will always return the same value as [`On::target`].
+    ///
+    /// If the event was not targeted at a specific entity, this will return [`Entity::PLACEHOLDER`].
+    pub fn original_target(&self) -> Entity {
+        self.trigger.original_target.unwrap_or(Entity::PLACEHOLDER)
+    }
+
+    /// Enables or disables event propagation, allowing the same event to trigger observers on a chain of different entities.
+    ///
+    /// The path an event will propagate along is specified by its associated [`Traversal`] component. By default, events
+    /// use `()` which ends the path immediately and prevents propagation.
+    ///
+    /// To enable propagation, you must:
+    /// + Set [`EntityEvent::Traversal`] to the component you want to propagate along.
+    /// + Either call `propagate(true)` in the first observer or set [`EntityEvent::AUTO_PROPAGATE`] to `true`.
+    ///
+    /// You can prevent an event from propagating further using `propagate(false)`.
+    ///
+    /// [`Traversal`]: crate::traversal::Traversal
+    pub fn propagate(&mut self, should_propagate: bool) {
+        *self.propagate = should_propagate;
+    }
+
+    /// Returns the value of the flag that controls event propagation. See [`propagate`] for more information.
+    ///
+    /// [`propagate`]: On::propagate
+    pub fn get_propagate(&self) -> bool {
+        *self.propagate
+    }
+}
+
+impl<'w, E: Debug, B: Bundle> Debug for On<'w, E, B> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        f.debug_struct("On")
+            .field("event", &self.event)
+            .field("propagate", &self.propagate)
+            .field("trigger", &self.trigger)
+            .field("_marker", &self._marker)
+            .finish()
+    }
+}
+
+impl<'w, E, B: Bundle> Deref for On<'w, E, B> {
+    type Target = E;
+
+    fn deref(&self) -> &Self::Target {
+        self.event
+    }
+}
+
+impl<'w, E, B: Bundle> DerefMut for On<'w, E, B> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.event
+    }
+}
+
+/// Metadata about a specific [`Event`] that triggered an observer.
+///
+/// This information is exposed via methods on [`On`].
+#[derive(Debug)]
+pub struct ObserverTrigger {
+    /// The [`Entity`] of the observer handling the trigger.
+    pub observer: Entity,
+    /// The [`Event`] the trigger targeted.
+    pub event_type: ComponentId,
+    /// The [`ComponentId`]s the trigger targeted.
+    pub components: SmallVec<[ComponentId; 2]>,
+    /// The entity that the entity-event targeted, if any.
+    ///
+    /// Note that if event propagation is enabled, this may not be the same as [`ObserverTrigger::original_target`].
+    pub current_target: Option<Entity>,
+    /// The entity that the entity-event was originally targeted at, if any.
+    ///
+    /// If event propagation is enabled, this will be the first entity that the event was targeted at,
+    /// even if the event was propagated to other entities.
+    pub original_target: Option<Entity>,
+    /// The location of the source code that triggered the observer.
+    pub caller: MaybeLocation,
+}
+
+impl ObserverTrigger {
+    /// Returns the components that the trigger targeted.
+    pub fn components(&self) -> &[ComponentId] {
+        &self.components
+    }
+}

crates/bevy_ecs/src/observer/trigger_targets.rs

@@ -0,0 +1,117 @@
+//! Stores the [`TriggerTargets`] trait.
+
+use crate::{component::ComponentId, prelude::*};
+use alloc::vec::Vec;
+use variadics_please::all_tuples;
+
+/// Represents a collection of targets for a specific [`On`] instance of an [`Event`].
+///
+/// When an event is triggered with [`TriggerTargets`], any [`Observer`] that watches for that specific
+/// event-target combination will run.
+///
+/// This trait is implemented for both [`Entity`] and [`ComponentId`], allowing you to target specific entities or components.
+/// It is also implemented for various collections of these types, such as [`Vec`], arrays, and tuples,
+/// allowing you to trigger events for multiple targets at once.
+pub trait TriggerTargets {
+    /// The components the trigger should target.
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_;
+
+    /// The entities the trigger should target.
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_;
+}
+
+impl<T: TriggerTargets + ?Sized> TriggerTargets for &T {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        (**self).components()
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        (**self).entities()
+    }
+}
+
+impl TriggerTargets for Entity {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        [].into_iter()
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        core::iter::once(*self)
+    }
+}
+
+impl TriggerTargets for ComponentId {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        core::iter::once(*self)
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        [].into_iter()
+    }
+}
+
+impl<T: TriggerTargets> TriggerTargets for Vec<T> {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        self.iter().flat_map(T::components)
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        self.iter().flat_map(T::entities)
+    }
+}
+
+impl<const N: usize, T: TriggerTargets> TriggerTargets for [T; N] {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        self.iter().flat_map(T::components)
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        self.iter().flat_map(T::entities)
+    }
+}
+
+impl<T: TriggerTargets> TriggerTargets for [T] {
+    fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+        self.iter().flat_map(T::components)
+    }
+
+    fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+        self.iter().flat_map(T::entities)
+    }
+}
+
+macro_rules! impl_trigger_targets_tuples {
+    ($(#[$meta:meta])* $($trigger_targets: ident),*) => {
+        #[expect(clippy::allow_attributes, reason = "can't guarantee violation of non_snake_case")]
+        #[allow(non_snake_case, reason = "`all_tuples!()` generates non-snake-case variable names.")]
+        $(#[$meta])*
+        impl<$($trigger_targets: TriggerTargets),*> TriggerTargets for ($($trigger_targets,)*)
+        {
+            fn components(&self) -> impl Iterator<Item = ComponentId> + Clone + '_ {
+                let iter = [].into_iter();
+                let ($($trigger_targets,)*) = self;
+                $(
+                    let iter = iter.chain($trigger_targets.components());
+                )*
+                iter
+            }
+
+            fn entities(&self) -> impl Iterator<Item = Entity> + Clone + '_ {
+                let iter = [].into_iter();
+                let ($($trigger_targets,)*) = self;
+                $(
+                    let iter = iter.chain($trigger_targets.entities());
+                )*
+                iter
+            }
+        }
+    }
+}
+
+all_tuples!(
+    #[doc(fake_variadic)]
+    impl_trigger_targets_tuples,
+    0,
+    15,
+    T
+);

crates/bevy_ecs/src/query/fetch.rs

@@ -1489,6 +1489,7 @@ impl<T: Component> Clone for ReadFetch<'_, T> {
         *self
     }
 }
+
 impl<T: Component> Copy for ReadFetch<'_, T> {}
 
 /// SAFETY:
@@ -1665,6 +1666,7 @@ impl<T: Component> Clone for RefFetch<'_, T> {
         *self
     }
 }
+
 impl<T: Component> Copy for RefFetch<'_, T> {}
 
 /// SAFETY:
@@ -1873,6 +1875,7 @@ impl<T: Component> Clone for WriteFetch<'_, T> {
         *self
     }
 }
+
 impl<T: Component> Copy for WriteFetch<'_, T> {}
 
 /// SAFETY:

crates/bevy_ecs/src/query/filter.rs

@@ -1240,6 +1240,7 @@ unsafe impl QueryFilter for Spawned {
 pub trait ArchetypeFilter: QueryFilter {}
 
 impl<T: Component> ArchetypeFilter for With<T> {}
+
 impl<T: Component> ArchetypeFilter for Without<T> {}
 
 macro_rules! impl_archetype_filter_tuple {

crates/bevy_ecs/src/query/mod.rs

@@ -507,7 +507,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "&mut bevy_ecs::query::tests::A conflicts with a previous access in this query."]
+    #[should_panic]
     fn self_conflicting_worldquery() {
         #[derive(QueryData)]
         #[query_data(mutable)]

crates/bevy_ecs/src/query/state.rs

@@ -1901,9 +1901,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for ((&bevy_ecs::query::state::tests::A, &bevy_ecs::query::state::tests::B), ()) attempts to access terms that are not allowed by original state (&bevy_ecs::query::state::tests::A, ())."
-    )]
     fn cannot_transmute_to_include_data_not_in_original_query() {
         let mut world = World::new();
         world.register_component::<A>();
@@ -1915,9 +1913,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for (&mut bevy_ecs::query::state::tests::A, ()) attempts to access terms that are not allowed by original state (&bevy_ecs::query::state::tests::A, ())."
-    )]
     fn cannot_transmute_immut_to_mut() {
         let mut world = World::new();
         world.spawn(A(0));
@@ -1927,9 +1923,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for (&bevy_ecs::query::state::tests::A, ()) attempts to access terms that are not allowed by original state (core::option::Option<&bevy_ecs::query::state::tests::A>, ())."
-    )]
     fn cannot_transmute_option_to_immut() {
         let mut world = World::new();
         world.spawn(C(0));
@@ -1941,9 +1935,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for (&bevy_ecs::query::state::tests::A, ()) attempts to access terms that are not allowed by original state (bevy_ecs::world::entity_ref::EntityRef, ())."
-    )]
     fn cannot_transmute_entity_ref() {
         let mut world = World::new();
         world.register_component::<A>();
@@ -2009,9 +2001,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for (bevy_ecs::entity::Entity, bevy_ecs::query::filter::Changed<bevy_ecs::query::state::tests::B>) attempts to access terms that are not allowed by original state (&bevy_ecs::query::state::tests::A, ())."
-    )]
     fn cannot_transmute_changed_without_access() {
         let mut world = World::new();
         world.register_component::<A>();
@@ -2021,9 +2011,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Transmuted state for (&mut bevy_ecs::query::state::tests::A, ()) attempts to access terms that are not allowed by original state (&bevy_ecs::query::state::tests::A, ())."
-    )]
     fn cannot_transmute_mutable_after_readonly() {
         let mut world = World::new();
         // Calling this method would mean we had aliasing queries.
@@ -2130,9 +2118,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(expected = "Joined state for (&bevy_ecs::query::state::tests::C, ()) \
+    #[should_panic]
-            attempts to access terms that are not allowed by state \
-            (&bevy_ecs::query::state::tests::A, ()) joined with (&bevy_ecs::query::state::tests::B, ()).")]
     fn cannot_join_wrong_fetch() {
         let mut world = World::new();
         world.register_component::<C>();
@@ -2142,12 +2128,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Joined state for (bevy_ecs::entity::Entity, bevy_ecs::query::filter::Changed<bevy_ecs::query::state::tests::C>) \
-            attempts to access terms that are not allowed by state \
-            (&bevy_ecs::query::state::tests::A, bevy_ecs::query::filter::Without<bevy_ecs::query::state::tests::C>) \
-            joined with (&bevy_ecs::query::state::tests::B, bevy_ecs::query::filter::Without<bevy_ecs::query::state::tests::C>)."
-    )]
     fn cannot_join_wrong_filter() {
         let mut world = World::new();
         let query_1 = QueryState::<&A, Without<C>>::new(&mut world);
@@ -2156,9 +2137,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "Joined state for ((&mut bevy_ecs::query::state::tests::A, &mut bevy_ecs::query::state::tests::B), ()) attempts to access terms that are not allowed by state (&bevy_ecs::query::state::tests::A, ()) joined with (&mut bevy_ecs::query::state::tests::B, ())."
-    )]
     fn cannot_join_mutable_after_readonly() {
         let mut world = World::new();
         // Calling this method would mean we had aliasing queries.

crates/bevy_ecs/src/relationship/mod.rs

@@ -82,6 +82,20 @@ pub trait Relationship: Component + Sized {
     /// Creates this [`Relationship`] from the given `entity`.
     fn from(entity: Entity) -> Self;
 
+    /// Changes the current [`Entity`] ID of the entity containing the [`RelationshipTarget`] to another one.
+    ///
+    /// This is useful for updating the relationship without overwriting other fields stored in `Self`.
+    ///
+    /// # Warning
+    ///
+    /// This should generally not be called by user code, as modifying the related entity could invalidate the
+    /// relationship. If this method is used, then the hooks [`on_replace`](Relationship::on_replace) have to
+    /// run before and [`on_insert`](Relationship::on_insert) after it.
+    /// This happens automatically when this method is called with [`EntityWorldMut::modify_component`].
+    ///
+    /// Prefer to use regular means of insertions when possible.
+    fn set_risky(&mut self, entity: Entity);
+
     /// The `on_insert` component hook that maintains the [`Relationship`] / [`RelationshipTarget`] connection.
     fn on_insert(
         mut world: DeferredWorld,

crates/bevy_ecs/src/relationship/related_methods.rs

@@ -6,7 +6,7 @@ use crate::{
         Relationship, RelationshipHookMode, RelationshipSourceCollection, RelationshipTarget,
     },
     system::{Commands, EntityCommands},
-    world::{EntityWorldMut, World},
+    world::{DeferredWorld, EntityWorldMut, World},
 };
 use bevy_platform::prelude::{Box, Vec};
 use core::{marker::PhantomData, mem};
@@ -42,7 +42,12 @@ impl<'w> EntityWorldMut<'w> {
         let id = self.id();
         self.world_scope(|world| {
             for related in related {
-                world.entity_mut(*related).insert(R::from(id));
+                world
+                    .entity_mut(*related)
+                    .modify_or_insert_relation_with_relationship_hook_mode::<R>(
+                        id,
+                        RelationshipHookMode::Run,
+                    );
             }
         });
         self
@@ -98,7 +103,12 @@ impl<'w> EntityWorldMut<'w> {
                         .collection_mut_risky()
                         .place(*related, index);
                 } else {
-                    world.entity_mut(*related).insert(R::from(id));
+                    world
+                        .entity_mut(*related)
+                        .modify_or_insert_relation_with_relationship_hook_mode::<R>(
+                            id,
+                            RelationshipHookMode::Run,
+                        );
                     world
                         .get_mut::<R::RelationshipTarget>(id)
                         .expect("hooks should have added relationship target")
@@ -165,10 +175,13 @@ impl<'w> EntityWorldMut<'w> {
             }
 
             for related in potential_relations {
-                // SAFETY: We'll manually be adjusting the contents of the parent to fit the final state.
+                // SAFETY: We'll manually be adjusting the contents of the `RelationshipTarget` to fit the final state.
                 world
                     .entity_mut(related)
-                    .insert_with_relationship_hook_mode(R::from(id), RelationshipHookMode::Skip);
+                    .modify_or_insert_relation_with_relationship_hook_mode::<R>(
+                        id,
+                        RelationshipHookMode::Skip,
+                    );
             }
         });
 
@@ -266,7 +279,10 @@ impl<'w> EntityWorldMut<'w> {
                 // We changed the target collection manually so don't run the insert hook
                 world
                     .entity_mut(*new_relation)
-                    .insert_with_relationship_hook_mode(R::from(this), RelationshipHookMode::Skip);
+                    .modify_or_insert_relation_with_relationship_hook_mode::<R>(
+                        this,
+                        RelationshipHookMode::Skip,
+                    );
             }
         });
 
@@ -352,6 +368,40 @@ impl<'w> EntityWorldMut<'w> {
 
         self
     }
+
+    fn modify_or_insert_relation_with_relationship_hook_mode<R: Relationship>(
+        &mut self,
+        entity: Entity,
+        relationship_hook_mode: RelationshipHookMode,
+    ) {
+        // Check if the relation edge holds additional data
+        if size_of::<R>() > size_of::<Entity>() {
+            self.assert_not_despawned();
+
+            let this = self.id();
+
+            let modified = self.world_scope(|world| {
+                let modified = DeferredWorld::from(&mut *world)
+                    .modify_component_with_relationship_hook_mode::<R, _>(
+                        this,
+                        relationship_hook_mode,
+                        |r| r.set_risky(entity),
+                    )
+                    .expect("entity access must be valid")
+                    .is_some();
+
+                world.flush();
+
+                modified
+            });
+
+            if modified {
+                return;
+            }
+        }
+
+        self.insert_with_relationship_hook_mode(R::from(entity), relationship_hook_mode);
+    }
 }
 
 impl<'a> EntityCommands<'a> {
@@ -689,17 +739,132 @@ mod tests {
     }
 
     #[test]
-    fn replace_related_keeps_data() {
+    fn add_related_keeps_relationship_data() {
-        #[derive(Component)]
+        #[derive(Component, PartialEq, Debug)]
         #[relationship(relationship_target = Parent)]
-        pub struct Child(Entity);
+        struct Child {
+            #[relationship]
+            parent: Entity,
+            data: u8,
+        }
 
         #[derive(Component)]
         #[relationship_target(relationship = Child)]
-        pub struct Parent {
+        struct Parent(Vec<Entity>);
+
+        let mut world = World::new();
+        let parent1 = world.spawn_empty().id();
+        let parent2 = world.spawn_empty().id();
+        let child = world
+            .spawn(Child {
+                parent: parent1,
+                data: 42,
+            })
+            .id();
+
+        world.entity_mut(parent2).add_related::<Child>(&[child]);
+        assert_eq!(
+            world.get::<Child>(child),
+            Some(&Child {
+                parent: parent2,
+                data: 42
+            })
+        );
+    }
+
+    #[test]
+    fn insert_related_keeps_relationship_data() {
+        #[derive(Component, PartialEq, Debug)]
+        #[relationship(relationship_target = Parent)]
+        struct Child {
+            #[relationship]
+            parent: Entity,
+            data: u8,
+        }
+
+        #[derive(Component)]
+        #[relationship_target(relationship = Child)]
+        struct Parent(Vec<Entity>);
+
+        let mut world = World::new();
+        let parent1 = world.spawn_empty().id();
+        let parent2 = world.spawn_empty().id();
+        let child = world
+            .spawn(Child {
+                parent: parent1,
+                data: 42,
+            })
+            .id();
+
+        world
+            .entity_mut(parent2)
+            .insert_related::<Child>(0, &[child]);
+        assert_eq!(
+            world.get::<Child>(child),
+            Some(&Child {
+                parent: parent2,
+                data: 42
+            })
+        );
+    }
+
+    #[test]
+    fn replace_related_keeps_relationship_data() {
+        #[derive(Component, PartialEq, Debug)]
+        #[relationship(relationship_target = Parent)]
+        struct Child {
+            #[relationship]
+            parent: Entity,
+            data: u8,
+        }
+
+        #[derive(Component)]
+        #[relationship_target(relationship = Child)]
+        struct Parent(Vec<Entity>);
+
+        let mut world = World::new();
+        let parent1 = world.spawn_empty().id();
+        let parent2 = world.spawn_empty().id();
+        let child = world
+            .spawn(Child {
+                parent: parent1,
+                data: 42,
+            })
+            .id();
+
+        world
+            .entity_mut(parent2)
+            .replace_related_with_difference::<Child>(&[], &[child], &[child]);
+        assert_eq!(
+            world.get::<Child>(child),
+            Some(&Child {
+                parent: parent2,
+                data: 42
+            })
+        );
+
+        world.entity_mut(parent1).replace_related::<Child>(&[child]);
+        assert_eq!(
+            world.get::<Child>(child),
+            Some(&Child {
+                parent: parent1,
+                data: 42
+            })
+        );
+    }
+
+    #[test]
+    fn replace_related_keeps_relationship_target_data() {
+        #[derive(Component)]
+        #[relationship(relationship_target = Parent)]
+        struct Child(Entity);
+
+        #[derive(Component)]
+        #[relationship_target(relationship = Child)]
+        struct Parent {
             #[relationship]
             children: Vec<Entity>,
-            pub data: u8,
+            data: u8,
         }
 
         let mut world = World::new();

crates/bevy_ecs/src/schedule/mod.rs

@@ -26,7 +26,9 @@ pub mod passes {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use alloc::{string::ToString, vec, vec::Vec};
+    #[cfg(feature = "trace")]
+    use alloc::string::ToString;
+    use alloc::{vec, vec::Vec};
     use core::sync::atomic::{AtomicU32, Ordering};
 
     use crate::error::BevyError;
@@ -770,6 +772,7 @@ mod tests {
     }
 
     mod system_ambiguity {
+        #[cfg(feature = "trace")]
         use alloc::collections::BTreeSet;
 
         use super::*;
@@ -1110,6 +1113,7 @@ mod tests {
 
         // Tests that the correct ambiguities were reported in the correct order.
         #[test]
+        #[cfg(feature = "trace")]
         fn correct_ambiguities() {
             fn system_a(_res: ResMut<R>) {}
             fn system_b(_res: ResMut<R>) {}
@@ -1183,6 +1187,7 @@ mod tests {
         // Test that anonymous set names work properly
         // Related issue https://github.com/bevyengine/bevy/issues/9641
         #[test]
+        #[cfg(feature = "trace")]
         fn anonymous_set_name() {
             let mut schedule = Schedule::new(TestSchedule);
             schedule.add_systems((resmut_system, resmut_system).run_if(|| true));

crates/bevy_ecs/src/schedule/pass.rs

@@ -51,6 +51,7 @@ pub(super) trait ScheduleBuildPassObj: Send + Sync + Debug {
     );
     fn add_dependency(&mut self, from: NodeId, to: NodeId, all_options: &TypeIdMap<Box<dyn Any>>);
 }
+
 impl<T: ScheduleBuildPass> ScheduleBuildPassObj for T {
     fn build(
         &mut self,

crates/bevy_ecs/src/schedule/schedule.rs

@@ -235,6 +235,7 @@ pub enum Chain {
     /// will be added between the successive elements.
     Chained(TypeIdMap<Box<dyn Any>>),
 }
+
 impl Chain {
     /// Specify that the systems must be chained.
     pub fn set_chained(&mut self) {

crates/bevy_ecs/src/spawn.rs

@@ -210,6 +210,7 @@ unsafe impl<R: Relationship, L: SpawnableList<R> + Send + Sync + 'static> Bundle
         );
     }
 }
+
 impl<R: Relationship, L: SpawnableList<R>> DynamicBundle for SpawnRelatedBundle<R, L> {
     type Effect = Self;
 

crates/bevy_ecs/src/system/commands/command.rs

@@ -223,6 +223,7 @@ pub fn trigger(event: impl Event) -> impl Command {
 }
 
 /// A [`Command`] that sends an [`EntityEvent`] for the given targets.
+#[track_caller]
 pub fn trigger_targets(
     event: impl EntityEvent,
     targets: impl TriggerTargets + Send + Sync + 'static,

crates/bevy_ecs/src/system/commands/mod.rs

@@ -2392,7 +2392,7 @@ mod tests {
             .spawn((W(1u32), W(2u64)))
             .id();
         command_queue.apply(&mut world);
-        assert_eq!(world.entities().count_constructed(), 1);
+        assert_eq!(world.entity_count(), 1);
         let results = world
             .query::<(&W<u32>, &W<u64>)>()
             .iter(&world)

crates/bevy_ecs/src/system/mod.rs

@@ -634,7 +634,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "&bevy_ecs::system::tests::A conflicts with a previous access in this query."]
+    #[should_panic]
     fn any_of_with_mut_and_ref() {
         fn sys(_: Query<AnyOf<(&mut A, &A)>>) {}
         let mut world = World::default();
@@ -642,7 +642,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "&mut bevy_ecs::system::tests::A conflicts with a previous access in this query."]
+    #[should_panic]
     fn any_of_with_ref_and_mut() {
         fn sys(_: Query<AnyOf<(&A, &mut A)>>) {}
         let mut world = World::default();
@@ -650,7 +650,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "&bevy_ecs::system::tests::A conflicts with a previous access in this query."]
+    #[should_panic]
     fn any_of_with_mut_and_option() {
         fn sys(_: Query<AnyOf<(&mut A, Option<&A>)>>) {}
         let mut world = World::default();
@@ -680,7 +680,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "&mut bevy_ecs::system::tests::A conflicts with a previous access in this query."]
+    #[should_panic]
     fn any_of_with_conflicting() {
         fn sys(_: Query<AnyOf<(&mut A, &mut A)>>) {}
         let mut world = World::default();
@@ -1629,54 +1629,42 @@ mod tests {
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "error[B0001]: Query<EntityMut, ()> in system bevy_ecs::system::tests::assert_world_and_entity_mut_system_does_conflict_first::system accesses component(s) in a way that conflicts with a previous system parameter. Consider using `Without<T>` to create disjoint Queries or merging conflicting Queries into a `ParamSet`. See: https://bevy.org/learn/errors/b0001"
-    )]
     fn assert_world_and_entity_mut_system_does_conflict_first() {
         fn system(_query: &World, _q2: Query<EntityMut>) {}
         super::assert_system_does_not_conflict(system);
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "&World conflicts with a previous mutable system parameter. Allowing this would break Rust's mutability rules"
-    )]
     fn assert_world_and_entity_mut_system_does_conflict_second() {
         fn system(_: Query<EntityMut>, _: &World) {}
         super::assert_system_does_not_conflict(system);
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "error[B0001]: Query<EntityMut, ()> in system bevy_ecs::system::tests::assert_entity_ref_and_entity_mut_system_does_conflict::system accesses component(s) in a way that conflicts with a previous system parameter. Consider using `Without<T>` to create disjoint Queries or merging conflicting Queries into a `ParamSet`. See: https://bevy.org/learn/errors/b0001"
-    )]
     fn assert_entity_ref_and_entity_mut_system_does_conflict() {
         fn system(_query: Query<EntityRef>, _q2: Query<EntityMut>) {}
         super::assert_system_does_not_conflict(system);
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "error[B0001]: Query<EntityMut, ()> in system bevy_ecs::system::tests::assert_entity_mut_system_does_conflict::system accesses component(s) in a way that conflicts with a previous system parameter. Consider using `Without<T>` to create disjoint Queries or merging conflicting Queries into a `ParamSet`. See: https://bevy.org/learn/errors/b0001"
-    )]
     fn assert_entity_mut_system_does_conflict() {
         fn system(_query: Query<EntityMut>, _q2: Query<EntityMut>) {}
         super::assert_system_does_not_conflict(system);
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "error[B0001]: Query<EntityRef, ()> in system bevy_ecs::system::tests::assert_deferred_world_and_entity_ref_system_does_conflict_first::system accesses component(s) in a way that conflicts with a previous system parameter. Consider using `Without<T>` to create disjoint Queries or merging conflicting Queries into a `ParamSet`. See: https://bevy.org/learn/errors/b0001"
-    )]
     fn assert_deferred_world_and_entity_ref_system_does_conflict_first() {
         fn system(_world: DeferredWorld, _query: Query<EntityRef>) {}
         super::assert_system_does_not_conflict(system);
     }
 
     #[test]
-    #[should_panic(
+    #[should_panic]
-        expected = "DeferredWorld in system bevy_ecs::system::tests::assert_deferred_world_and_entity_ref_system_does_conflict_second::system conflicts with a previous access."
-    )]
     fn assert_deferred_world_and_entity_ref_system_does_conflict_second() {
         fn system(_query: Query<EntityRef>, _world: DeferredWorld) {}
         super::assert_system_does_not_conflict(system);

crates/bevy_ecs/src/system/observer_system.rs

@@ -73,6 +73,7 @@ where
         InfallibleObserverWrapper::new(IntoSystem::into_system(this))
     }
 }
+
 impl<E, B, M, S> IntoObserverSystem<E, B, (Never, M), Result> for S
 where
     S: IntoSystem<On<'static, E, B>, Never, M> + Send + 'static,

crates/bevy_ecs/src/system/system.rs

@@ -410,7 +410,6 @@ pub enum RunSystemError {
 mod tests {
     use super::*;
     use crate::prelude::*;
-    use alloc::string::ToString;
 
     #[test]
     fn run_system_once() {
@@ -483,7 +482,5 @@ mod tests {
         let result = world.run_system_once(system);
 
         assert!(matches!(result, Err(RunSystemError::InvalidParams { .. })));
-        let expected = "System bevy_ecs::system::system::tests::run_system_once_invalid_params::system did not run due to failed parameter validation: Parameter `Res<T>` failed validation: Resource does not exist\nIf this is an expected state, wrap the parameter in `Option<T>` and handle `None` when it happens, or wrap the parameter in `When<T>` to skip the system when it happens.";
-        assert_eq!(expected, result.unwrap_err().to_string());
     }
 }

crates/bevy_ecs/src/system/system_name.rs

@@ -85,6 +85,7 @@ impl ExclusiveSystemParam for SystemName {
 }
 
 #[cfg(test)]
+#[cfg(feature = "trace")]
 mod tests {
     use crate::{
         system::{IntoSystem, RunSystemOnce, SystemName},

crates/bevy_ecs/src/system/system_param.rs

@@ -151,6 +151,7 @@ use variadics_please::{all_tuples, all_tuples_enumerated};
 /// let mut world = World::new();
 /// let err = world.run_system_cached(|param: MyParam| {}).unwrap_err();
 /// let expected = "Parameter `MyParam::foo` failed validation: Custom Message";
+/// # #[cfg(feature="Trace")] // Without debug_utils/debug enabled MyParam::foo is stripped and breaks the assert
 /// assert!(err.to_string().contains(expected));
 /// ```
 ///
@@ -1399,6 +1400,7 @@ impl<'w, T> Deref for NonSend<'w, T> {
         self.value
     }
 }
+
 impl<'a, T> From<NonSendMut<'a, T>> for NonSend<'a, T> {
     fn from(nsm: NonSendMut<'a, T>) -> Self {
         Self {
@@ -3105,7 +3107,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "Encountered an error in system `bevy_ecs::system::system_param::tests::missing_resource_error::res_system`: Parameter `Res<MissingResource>` failed validation: Resource does not exist"]
+    #[should_panic]
     fn missing_resource_error() {
         #[derive(Resource)]
         pub struct MissingResource;
@@ -3119,7 +3121,7 @@ mod tests {
     }
 
     #[test]
-    #[should_panic = "Encountered an error in system `bevy_ecs::system::system_param::tests::missing_event_error::event_system`: Parameter `EventReader<MissingEvent>::events` failed validation: BufferedEvent not initialized"]
+    #[should_panic]
     fn missing_event_error() {
         use crate::prelude::{BufferedEvent, EventReader};
 

crates/bevy_ecs/src/system/system_registry.rs

@@ -913,7 +913,6 @@ mod tests {
     #[test]
     fn run_system_invalid_params() {
         use crate::system::RegisteredSystemError;
-        use alloc::{format, string::ToString};
 
         struct T;
         impl Resource for T {}
@@ -928,8 +927,6 @@ mod tests {
             result,
             Err(RegisteredSystemError::InvalidParams { .. })
         ));
-        let expected = format!("System {id:?} did not run due to failed parameter validation: Parameter `Res<T>` failed validation: Resource does not exist\nIf this is an expected state, wrap the parameter in `Option<T>` and handle `None` when it happens, or wrap the parameter in `When<T>` to skip the system when it happens.");
-        assert_eq!(expected, result.unwrap_err().to_string());
     }
 
     #[test]

crates/bevy_ecs/src/world/command_queue.rs

@@ -420,12 +420,12 @@ mod test {
         let mut world = World::new();
         queue.apply(&mut world);
 
-        assert_eq!(world.entities().count_constructed(), 2);
+        assert_eq!(world.entity_count(), 2);
 
         // The previous call to `apply` cleared the queue.
         // This call should do nothing.
         queue.apply(&mut world);
-        assert_eq!(world.entities().count_constructed(), 2);
+        assert_eq!(world.entity_count(), 2);
     }
 
     #[expect(
@@ -459,7 +459,7 @@ mod test {
         queue.push(SpawnCommand);
         queue.push(SpawnCommand);
         queue.apply(&mut world);
-        assert_eq!(world.entities().count_constructed(), 3);
+        assert_eq!(world.entity_count(), 3);
     }
 
     #[test]

crates/bevy_ecs/src/world/deferred_world.rs

@@ -102,9 +102,11 @@ impl<'w> DeferredWorld<'w> {
     /// If you do not need to ensure the above hooks are triggered, and your component
     /// is mutable, prefer using [`get_mut`](DeferredWorld::get_mut).
     #[inline]
-    pub(crate) fn modify_component<T: Component, R>(
+    #[track_caller]
+    pub(crate) fn modify_component_with_relationship_hook_mode<T: Component, R>(
         &mut self,
         entity: Entity,
+        relationship_hook_mode: RelationshipHookMode,
         f: impl FnOnce(&mut T) -> R,
     ) -> Result<Option<R>, EntityMutableFetchError> {
         // If the component is not registered, then it doesn't exist on this entity, so no action required.
@@ -112,12 +114,17 @@ impl<'w> DeferredWorld<'w> {
             return Ok(None);
         };
 
-        self.modify_component_by_id(entity, component_id, move |component| {
+        self.modify_component_by_id_with_relationship_hook_mode(
-            // SAFETY: component matches the component_id collected in the above line
+            entity,
-            let mut component = unsafe { component.with_type::<T>() };
+            component_id,
+            relationship_hook_mode,
+            move |component| {
+                // SAFETY: component matches the component_id collected in the above line
+                let mut component = unsafe { component.with_type::<T>() };
 
-            f(&mut component)
+                f(&mut component)
-        })
+            },
+        )
     }
 
     /// Temporarily removes a [`Component`] identified by the provided
@@ -132,13 +139,15 @@ impl<'w> DeferredWorld<'w> {
     /// If you do not need to ensure the above hooks are triggered, and your component
     /// is mutable, prefer using [`get_mut_by_id`](DeferredWorld::get_mut_by_id).
     ///
-    /// You should prefer the typed [`modify_component`](DeferredWorld::modify_component)
+    /// You should prefer the typed [`modify_component_with_relationship_hook_mode`](DeferredWorld::modify_component_with_relationship_hook_mode)
     /// whenever possible.
     #[inline]
-    pub(crate) fn modify_component_by_id<R>(
+    #[track_caller]
+    pub(crate) fn modify_component_by_id_with_relationship_hook_mode<R>(
         &mut self,
         entity: Entity,
         component_id: ComponentId,
+        relationship_hook_mode: RelationshipHookMode,
         f: impl for<'a> FnOnce(MutUntyped<'a>) -> R,
     ) -> Result<Option<R>, EntityMutableFetchError> {
         let entity_cell = self.get_entity_mut(entity)?;
@@ -162,7 +171,7 @@ impl<'w> DeferredWorld<'w> {
                 entity,
                 [component_id].into_iter(),
                 MaybeLocation::caller(),
-                RelationshipHookMode::Run,
+                relationship_hook_mode,
             );
             if archetype.has_replace_observer() {
                 self.trigger_observers(
@@ -202,7 +211,7 @@ impl<'w> DeferredWorld<'w> {
                 entity,
                 [component_id].into_iter(),
                 MaybeLocation::caller(),
-                RelationshipHookMode::Run,
+                relationship_hook_mode,
             );
             if archetype.has_insert_observer() {
                 self.trigger_observers(

crates/bevy_ecs/src/world/mod.rs

@@ -219,6 +219,14 @@ impl World {
         &mut self.entities
     }
 
+    /// Retrieves the number of [`Entities`] in the world.
+    ///
+    /// This is helpful as a diagnostic, but it can also be used effectively in tests.
+    #[inline]
+    pub fn entity_count(&self) -> u32 {
+        self.entities.len()
+    }
+
     /// Retrieves this world's [`Archetypes`] collection.
     #[inline]
     pub fn archetypes(&self) -> &Archetypes {
@@ -1426,6 +1434,7 @@ impl World {
     /// # assert_eq!(world.get::<Foo>(entity), Some(&Foo(true)));
     /// ```
     #[inline]
+    #[track_caller]
     pub fn modify_component<T: Component, R>(
         &mut self,
         entity: Entity,
@@ -1433,7 +1442,11 @@ impl World {
     ) -> Result<Option<R>, EntityMutableFetchError> {
         let mut world = DeferredWorld::from(&mut *self);
 
-        let result = world.modify_component(entity, f)?;
+        let result = world.modify_component_with_relationship_hook_mode(
+            entity,
+            RelationshipHookMode::Run,
+            f,
+        )?;
 
         self.flush();
         Ok(result)
@@ -1454,6 +1467,7 @@ impl World {
     /// You should prefer the typed [`modify_component`](World::modify_component)
     /// whenever possible.
     #[inline]
+    #[track_caller]
     pub fn modify_component_by_id<R>(
         &mut self,
         entity: Entity,
@@ -1462,7 +1476,12 @@ impl World {
     ) -> Result<Option<R>, EntityMutableFetchError> {
         let mut world = DeferredWorld::from(&mut *self);
 
-        let result = world.modify_component_by_id(entity, component_id, f)?;
+        let result = world.modify_component_by_id_with_relationship_hook_mode(
+            entity,
+            component_id,
+            RelationshipHookMode::Run,
+            f,
+        )?;
 
         self.flush();
         Ok(result)

crates/bevy_encase_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_encase_derive"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Bevy derive macro for encase"
 homepage = "https://bevy.org"
@@ -12,7 +12,7 @@ keywords = ["bevy"]
 proc-macro = true
 
 [dependencies]
-bevy_macro_utils = { path = "../bevy_macro_utils", version = "0.16.0-dev" }
+bevy_macro_utils = { path = "../bevy_macro_utils", version = "0.17.0-dev" }
 encase_derive_impl = "0.10"
 
 [lints]

crates/bevy_gilrs/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_gilrs"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Gamepad system made using Gilrs for Bevy Engine"
 homepage = "https://bevy.org"
@@ -10,12 +10,12 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev" }
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev" }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
 ] }
 

crates/bevy_gilrs/src/lib.rs

@@ -47,6 +47,7 @@ pub(crate) struct Gilrs {
     #[cfg(not(target_arch = "wasm32"))]
     cell: SyncCell<gilrs::Gilrs>,
 }
+
 impl Gilrs {
     #[inline]
     pub fn with(&mut self, f: impl FnOnce(&mut gilrs::Gilrs)) {

crates/bevy_gizmos/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_gizmos"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides gizmos for Bevy Engine"
 homepage = "https://bevy.org"
@@ -15,21 +15,21 @@ bevy_render = ["dep:bevy_render", "bevy_core_pipeline"]
 
 [dependencies]
 # Bevy
-bevy_pbr = { path = "../bevy_pbr", version = "0.16.0-dev", optional = true }
+bevy_pbr = { path = "../bevy_pbr", version = "0.17.0-dev", optional = true }
-bevy_sprite = { path = "../bevy_sprite", version = "0.16.0-dev", optional = true }
+bevy_sprite = { path = "../bevy_sprite", version = "0.17.0-dev", optional = true }
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev", optional = true }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev", optional = true }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.16.0-dev", optional = true }
+bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.17.0-dev", optional = true }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_gizmos_macros = { path = "macros", version = "0.16.0-dev" }
+bevy_gizmos_macros = { path = "macros", version = "0.17.0-dev" }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev" }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev" }
 
 # other
 bytemuck = "1.0"

crates/bevy_gizmos/macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_gizmos_macros"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Derive implementations for bevy_gizmos"
 homepage = "https://bevy.org"
@@ -13,7 +13,7 @@ proc-macro = true
 
 
 [dependencies]
-bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.16.0-dev" }
+bevy_macro_utils = { path = "../../bevy_macro_utils", version = "0.17.0-dev" }
 
 syn = "2.0"
 proc-macro2 = "1.0"

crates/bevy_gizmos/src/grid.rs

@@ -172,6 +172,7 @@ where
         );
     }
 }
+
 impl<Config, Clear> GizmoBuffer<Config, Clear>
 where
     Config: GizmoConfigGroup,

crates/bevy_gltf/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_gltf"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Bevy Engine GLTF loading"
 homepage = "https://bevy.org"
@@ -18,25 +18,25 @@ pbr_specular_textures = ["bevy_pbr/pbr_specular_textures"]
 
 [dependencies]
 # bevy
-bevy_animation = { path = "../bevy_animation", version = "0.16.0-dev", optional = true }
+bevy_animation = { path = "../bevy_animation", version = "0.17.0-dev", optional = true }
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.16.0-dev" }
+bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_mesh = { path = "../bevy_mesh", version = "0.16.0-dev" }
+bevy_mesh = { path = "../bevy_mesh", version = "0.17.0-dev" }
-bevy_pbr = { path = "../bevy_pbr", version = "0.16.0-dev" }
+bevy_pbr = { path = "../bevy_pbr", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_scene = { path = "../bevy_scene", version = "0.16.0-dev", features = [
+bevy_scene = { path = "../bevy_scene", version = "0.17.0-dev", features = [
   "bevy_render",
 ] }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev" }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
   "serialize",
 ] }
@@ -66,7 +66,7 @@ smallvec = "1.11"
 tracing = { version = "0.1", default-features = false, features = ["std"] }
 
 [dev-dependencies]
-bevy_log = { path = "../bevy_log", version = "0.16.0-dev" }
+bevy_log = { path = "../bevy_log", version = "0.17.0-dev" }
 
 [lints]
 workspace = true

crates/bevy_image/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_image"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides image types for Bevy Engine"
 homepage = "https://bevy.org"
@@ -40,17 +40,17 @@ zstd = ["ruzstd"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev", features = [
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev", features = [
   "serialize",
   "wgpu-types",
 ] }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
 ] }
 
@@ -77,7 +77,7 @@ tracing = { version = "0.1", default-features = false, features = ["std"] }
 half = { version = "2.4.1" }
 
 [dev-dependencies]
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
 
 [lints]
 workspace = true

crates/bevy_image/src/texture_atlas.rs

@@ -34,6 +34,7 @@ pub struct TextureAtlasSources {
     /// Maps from a specific image handle to the index in `textures` where they can be found.
     pub texture_ids: HashMap<AssetId<Image>, usize>,
 }
+
 impl TextureAtlasSources {
     /// Retrieves the texture *section* index of the given `texture` handle.
     pub fn texture_index(&self, texture: impl Into<AssetId<Image>>) -> Option<usize> {

crates/bevy_input/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_input"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides input functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -60,14 +60,14 @@ libm = ["bevy_math/libm"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev", default-features = false }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev", default-features = false }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", features = [
   "glam",
 ], default-features = false, optional = true }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false }
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false }
 
 # other
 serde = { version = "1", features = [

crates/bevy_input_focus/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_input_focus"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Keyboard focus management"
 homepage = "https://bevy.org"
@@ -60,12 +60,13 @@ libm = ["bevy_math/libm", "bevy_window/libm"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev", default-features = false }
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev", default-features = false }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev", default-features = false }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev", default-features = false }
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev", default-features = false }
+bevy_picking = { path = "../bevy_picking", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", features = [
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev", default-features = false }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", features = [
   "glam",
 ], default-features = false, optional = true }
 

crates/bevy_input_focus/src/lib.rs

@@ -147,6 +147,15 @@ pub struct FocusedInput<E: BufferedEvent + Clone> {
     window: Entity,
 }
 
+/// An event which is used to set input focus. Trigger this on an entity, and it will bubble
+/// until it finds a focusable entity, and then set focus to it.
+#[derive(Clone, Event, EntityEvent)]
+#[entity_event(traversal = WindowTraversal, auto_propagate)]
+pub struct AcquireFocus {
+    /// The primary window entity.
+    window: Entity,
+}
+
 #[derive(QueryData)]
 /// These are for accessing components defined on the targeted entity
 pub struct WindowTraversal {
@@ -172,6 +181,24 @@ impl<E: BufferedEvent + Clone> Traversal<FocusedInput<E>> for WindowTraversal {
     }
 }
 
+impl Traversal<AcquireFocus> for WindowTraversal {
+    fn traverse(item: Self::Item<'_, '_>, event: &AcquireFocus) -> Option<Entity> {
+        let WindowTraversalItem { child_of, window } = item;
+
+        // Send event to parent, if it has one.
+        if let Some(child_of) = child_of {
+            return Some(child_of.parent());
+        };
+
+        // Otherwise, send it to the window entity (unless this is a window entity).
+        if window.is_none() {
+            return Some(event.window);
+        }
+
+        None
+    }
+}
+
 /// Plugin which sets up systems for dispatching bubbling keyboard and gamepad button events to the focused entity.
 ///
 /// To add bubbling to your own input events, add the [`dispatch_focused_input::<MyEvent>`](dispatch_focused_input) system to your app,

crates/bevy_input_focus/src/tab_navigation.rs

@@ -38,11 +38,12 @@ use bevy_input::{
     keyboard::{KeyCode, KeyboardInput},
     ButtonInput, ButtonState,
 };
-use bevy_window::PrimaryWindow;
+use bevy_picking::events::{Pointer, Press};
+use bevy_window::{PrimaryWindow, Window};
 use log::warn;
 use thiserror::Error;
 
-use crate::{FocusedInput, InputFocus, InputFocusVisible};
+use crate::{AcquireFocus, FocusedInput, InputFocus, InputFocusVisible};
 
 #[cfg(feature = "bevy_reflect")]
 use {
@@ -312,6 +313,31 @@ impl TabNavigation<'_, '_> {
     }
 }
 
+/// Observer which sets focus to the nearest ancestor that has tab index, using bubbling.
+pub(crate) fn acquire_focus(
+    mut ev: On<AcquireFocus>,
+    focusable: Query<(), With<TabIndex>>,
+    windows: Query<(), With<Window>>,
+    mut focus: ResMut<InputFocus>,
+) {
+    // If the entity has a TabIndex
+    if focusable.contains(ev.target()) {
+        // Stop and focus it
+        ev.propagate(false);
+        // Don't mutate unless we need to, for change detection
+        if focus.0 != Some(ev.target()) {
+            focus.0 = Some(ev.target());
+        }
+    } else if windows.contains(ev.target()) {
+        // Stop and clear focus
+        ev.propagate(false);
+        // Don't mutate unless we need to, for change detection
+        if focus.0.is_some() {
+            focus.clear();
+        }
+    }
+}
+
 /// Plugin for navigating between focusable entities using keyboard input.
 pub struct TabNavigationPlugin;
 
@@ -321,6 +347,8 @@ impl Plugin for TabNavigationPlugin {
 
         #[cfg(feature = "bevy_reflect")]
         app.register_type::<TabIndex>().register_type::<TabGroup>();
+        app.add_observer(acquire_focus);
+        app.add_observer(click_to_focus);
     }
 }
 
@@ -330,6 +358,30 @@ fn setup_tab_navigation(mut commands: Commands, window: Query<Entity, With<Prima
     }
 }
 
+fn click_to_focus(
+    ev: On<Pointer<Press>>,
+    mut focus_visible: ResMut<InputFocusVisible>,
+    windows: Query<Entity, With<PrimaryWindow>>,
+    mut commands: Commands,
+) {
+    // Because `Pointer` is a bubbling event, we don't want to trigger an `AcquireFocus` event
+    // for every ancestor, but only for the original entity. Also, users may want to stop
+    // propagation on the pointer event at some point along the bubbling chain, so we need our
+    // own dedicated event whose propagation we can control.
+    if ev.target() == ev.original_target() {
+        // Clicking hides focus
+        if focus_visible.0 {
+            focus_visible.0 = false;
+        }
+        // Search for a focusable parent entity, defaulting to window if none.
+        if let Ok(window) = windows.single() {
+            commands
+                .entity(ev.target())
+                .trigger(AcquireFocus { window });
+        }
+    }
+}
+
 /// Observer function which handles tab navigation.
 ///
 /// This observer responds to [`KeyCode::Tab`] events and Shift+Tab events,

crates/bevy_internal/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_internal"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "An internal Bevy crate used to facilitate optional dynamic linking via the 'dynamic_linking' feature"
 homepage = "https://bevy.org"
@@ -350,80 +350,80 @@ debug = ["bevy_utils/debug"]
 
 [dependencies]
 # bevy (no_std)
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false, features = [
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev", default-features = false }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev", default-features = false }
-bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.16.0-dev", default-features = false }
+bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.17.0-dev", default-features = false }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev", default-features = false, features = [
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev", default-features = false, features = [
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev", default-features = false, features = [
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
   "nostd-libm",
 ] }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "alloc",
 ] }
-bevy_ptr = { path = "../bevy_ptr", version = "0.16.0-dev", default-features = false }
+bevy_ptr = { path = "../bevy_ptr", version = "0.17.0-dev", default-features = false }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, features = [
   "smallvec",
 ] }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev", default-features = false, features = [
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev", default-features = false, features = [
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev", default-features = false, features = [
   "bevy-support",
   "bevy_reflect",
 ] }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev", default-features = false }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev", default-features = false }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", default-features = false }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", default-features = false }
 
 # bevy (std required)
-bevy_log = { path = "../bevy_log", version = "0.16.0-dev", optional = true }
+bevy_log = { path = "../bevy_log", version = "0.17.0-dev", optional = true }
 
 # bevy (optional)
-bevy_a11y = { path = "../bevy_a11y", optional = true, version = "0.16.0-dev", features = [
+bevy_a11y = { path = "../bevy_a11y", optional = true, version = "0.17.0-dev", features = [
   "bevy_reflect",
 ] }
-bevy_animation = { path = "../bevy_animation", optional = true, version = "0.16.0-dev" }
+bevy_animation = { path = "../bevy_animation", optional = true, version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", optional = true, version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", optional = true, version = "0.17.0-dev" }
-bevy_audio = { path = "../bevy_audio", optional = true, version = "0.16.0-dev" }
+bevy_audio = { path = "../bevy_audio", optional = true, version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", optional = true, version = "0.16.0-dev", default-features = false, features = [
+bevy_color = { path = "../bevy_color", optional = true, version = "0.17.0-dev", default-features = false, features = [
   "alloc",
   "bevy_reflect",
 ] }
-bevy_core_pipeline = { path = "../bevy_core_pipeline", optional = true, version = "0.16.0-dev" }
+bevy_core_pipeline = { path = "../bevy_core_pipeline", optional = true, version = "0.17.0-dev" }
-bevy_core_widgets = { path = "../bevy_core_widgets", optional = true, version = "0.16.0-dev" }
+bevy_core_widgets = { path = "../bevy_core_widgets", optional = true, version = "0.17.0-dev" }
-bevy_anti_aliasing = { path = "../bevy_anti_aliasing", optional = true, version = "0.16.0-dev" }
+bevy_anti_aliasing = { path = "../bevy_anti_aliasing", optional = true, version = "0.17.0-dev" }
-bevy_dev_tools = { path = "../bevy_dev_tools", optional = true, version = "0.16.0-dev" }
+bevy_dev_tools = { path = "../bevy_dev_tools", optional = true, version = "0.17.0-dev" }
-bevy_gilrs = { path = "../bevy_gilrs", optional = true, version = "0.16.0-dev" }
+bevy_gilrs = { path = "../bevy_gilrs", optional = true, version = "0.17.0-dev" }
-bevy_gizmos = { path = "../bevy_gizmos", optional = true, version = "0.16.0-dev", default-features = false }
+bevy_gizmos = { path = "../bevy_gizmos", optional = true, version = "0.17.0-dev", default-features = false }
-bevy_gltf = { path = "../bevy_gltf", optional = true, version = "0.16.0-dev" }
+bevy_gltf = { path = "../bevy_gltf", optional = true, version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", optional = true, version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", optional = true, version = "0.17.0-dev" }
-bevy_input_focus = { path = "../bevy_input_focus", optional = true, version = "0.16.0-dev", default-features = false, features = [
+bevy_input_focus = { path = "../bevy_input_focus", optional = true, version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_pbr = { path = "../bevy_pbr", optional = true, version = "0.16.0-dev" }
+bevy_pbr = { path = "../bevy_pbr", optional = true, version = "0.17.0-dev" }
-bevy_picking = { path = "../bevy_picking", optional = true, version = "0.16.0-dev" }
+bevy_picking = { path = "../bevy_picking", optional = true, version = "0.17.0-dev" }
-bevy_remote = { path = "../bevy_remote", optional = true, version = "0.16.0-dev" }
+bevy_remote = { path = "../bevy_remote", optional = true, version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", optional = true, version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", optional = true, version = "0.17.0-dev" }
-bevy_scene = { path = "../bevy_scene", optional = true, version = "0.16.0-dev" }
+bevy_scene = { path = "../bevy_scene", optional = true, version = "0.17.0-dev" }
-bevy_solari = { path = "../bevy_solari", optional = true, version = "0.16.0-dev" }
+bevy_solari = { path = "../bevy_solari", optional = true, version = "0.17.0-dev" }
-bevy_sprite = { path = "../bevy_sprite", optional = true, version = "0.16.0-dev" }
+bevy_sprite = { path = "../bevy_sprite", optional = true, version = "0.17.0-dev" }
-bevy_state = { path = "../bevy_state", optional = true, version = "0.16.0-dev", default-features = false, features = [
+bevy_state = { path = "../bevy_state", optional = true, version = "0.17.0-dev", default-features = false, features = [
   "bevy_app",
   "bevy_reflect",
 ] }
-bevy_text = { path = "../bevy_text", optional = true, version = "0.16.0-dev" }
+bevy_text = { path = "../bevy_text", optional = true, version = "0.17.0-dev" }
-bevy_ui = { path = "../bevy_ui", optional = true, version = "0.16.0-dev" }
+bevy_ui = { path = "../bevy_ui", optional = true, version = "0.17.0-dev" }
-bevy_window = { path = "../bevy_window", optional = true, version = "0.16.0-dev", default-features = false, features = [
+bevy_window = { path = "../bevy_window", optional = true, version = "0.17.0-dev", default-features = false, features = [
   "bevy_reflect",
 ] }
-bevy_winit = { path = "../bevy_winit", optional = true, version = "0.16.0-dev", default-features = false }
+bevy_winit = { path = "../bevy_winit", optional = true, version = "0.17.0-dev", default-features = false }
 
 [lints]
 workspace = true

crates/bevy_log/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_log"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides logging for Bevy Engine"
 homepage = "https://bevy.org"
@@ -14,10 +14,10 @@ trace_tracy_memory = ["dep:tracy-client"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev" }
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
 
 # other
 tracing-subscriber = { version = "0.3.1", features = [
@@ -40,7 +40,7 @@ android_log-sys = "0.3.0"
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 tracing-wasm = "0.2.1"
 # TODO: Assuming all wasm builds are for the browser. Require `no_std` support to break assumption.
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev", default-features = false, features = [
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev", default-features = false, features = [
   "web",
 ] }
 

crates/bevy_macro_utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_macro_utils"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "A collection of utils for Bevy Engine"
 homepage = "https://bevy.org"

crates/bevy_math/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_math"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides math functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -25,7 +25,7 @@ approx = { version = "0.5", default-features = false, optional = true }
 rand = { version = "0.8", default-features = false, optional = true }
 rand_distr = { version = "0.4.3", optional = true }
 smallvec = { version = "1.11" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev", default-features = false, features = [
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev", default-features = false, features = [
   "glam",
 ], optional = true }
 variadics_please = "1.1"

crates/bevy_math/src/cubic_splines/mod.rs

@@ -1347,6 +1347,7 @@ pub struct RationalSegment<P: VectorSpace> {
     /// The width of the domain of this segment.
     pub knot_span: f32,
 }
+
 impl<P: VectorSpace<Scalar = f32>> RationalSegment<P> {
     /// Instantaneous position of a point at parametric value `t` in `[0, 1]`.
     #[inline]

crates/bevy_math/src/primitives/dim2.rs

@@ -35,6 +35,7 @@ pub struct Circle {
     /// The radius of the circle
     pub radius: f32,
 }
+
 impl Primitive2d for Circle {}
 
 impl Default for Circle {
@@ -124,6 +125,7 @@ pub struct Arc2d {
     /// Half the angle defining the arc
     pub half_angle: f32,
 }
+
 impl Primitive2d for Arc2d {}
 
 impl Default for Arc2d {
@@ -290,6 +292,7 @@ pub struct CircularSector {
     #[cfg_attr(all(feature = "serialize", feature = "alloc"), serde(flatten))]
     pub arc: Arc2d,
 }
+
 impl Primitive2d for CircularSector {}
 
 impl Default for CircularSector {
@@ -433,6 +436,7 @@ pub struct CircularSegment {
     #[cfg_attr(all(feature = "serialize", feature = "alloc"), serde(flatten))]
     pub arc: Arc2d,
 }
+
 impl Primitive2d for CircularSegment {}
 
 impl Default for CircularSegment {
@@ -453,6 +457,7 @@ impl Measured2d for CircularSegment {
         self.chord_length() + self.arc_length()
     }
 }
+
 impl CircularSegment {
     /// Create a new [`CircularSegment`] from a `radius`, and an `angle`
     #[inline(always)]
@@ -788,6 +793,7 @@ pub struct Ellipse {
     /// This corresponds to the two perpendicular radii defining the ellipse.
     pub half_size: Vec2,
 }
+
 impl Primitive2d for Ellipse {}
 
 impl Default for Ellipse {
@@ -939,6 +945,7 @@ pub struct Annulus {
     /// The outer circle of the annulus
     pub outer_circle: Circle,
 }
+
 impl Primitive2d for Annulus {}
 
 impl Default for Annulus {
@@ -1036,6 +1043,7 @@ pub struct Rhombus {
     /// Size of the horizontal and vertical diagonals of the rhombus
     pub half_diagonals: Vec2,
 }
+
 impl Primitive2d for Rhombus {}
 
 impl Default for Rhombus {
@@ -1171,6 +1179,7 @@ pub struct Plane2d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Dir2,
 }
+
 impl Primitive2d for Plane2d {}
 
 impl Default for Plane2d {
@@ -1213,6 +1222,7 @@ pub struct Line2d {
     /// and its opposite direction
     pub direction: Dir2,
 }
+
 impl Primitive2d for Line2d {}
 
 /// A line segment defined by two endpoints in 2D space.
@@ -1232,6 +1242,7 @@ pub struct Segment2d {
     /// The endpoints of the line segment.
     pub vertices: [Vec2; 2],
 }
+
 impl Primitive2d for Segment2d {}
 
 impl Segment2d {
@@ -1504,6 +1515,7 @@ pub struct Polyline2d<const N: usize> {
     #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec2; N],
 }
+
 impl<const N: usize> Primitive2d for Polyline2d<N> {}
 
 impl<const N: usize> FromIterator<Vec2> for Polyline2d<N> {
@@ -1573,6 +1585,7 @@ pub struct Triangle2d {
     /// The vertices of the triangle
     pub vertices: [Vec2; 3],
 }
+
 impl Primitive2d for Triangle2d {}
 
 impl Default for Triangle2d {
@@ -1745,6 +1758,7 @@ pub struct Rectangle {
     /// Half of the width and height of the rectangle
     pub half_size: Vec2,
 }
+
 impl Primitive2d for Rectangle {}
 
 impl Default for Rectangle {
@@ -1838,6 +1852,7 @@ pub struct Polygon<const N: usize> {
     #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec2; N],
 }
+
 impl<const N: usize> Primitive2d for Polygon<N> {}
 
 impl<const N: usize> FromIterator<Vec2> for Polygon<N> {
@@ -1892,6 +1907,7 @@ pub struct ConvexPolygon<const N: usize> {
     #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     vertices: [Vec2; N],
 }
+
 impl<const N: usize> Primitive2d for ConvexPolygon<N> {}
 
 /// An error that happens when creating a [`ConvexPolygon`].
@@ -2013,6 +2029,7 @@ pub struct RegularPolygon {
     /// The number of sides
     pub sides: u32,
 }
+
 impl Primitive2d for RegularPolygon {}
 
 impl Default for RegularPolygon {
@@ -2160,6 +2177,7 @@ pub struct Capsule2d {
     /// Half the height of the capsule, excluding the semicircles
     pub half_length: f32,
 }
+
 impl Primitive2d for Capsule2d {}
 
 impl Default for Capsule2d {

crates/bevy_math/src/primitives/dim3.rs

@@ -31,6 +31,7 @@ pub struct Sphere {
     /// The radius of the sphere
     pub radius: f32,
 }
+
 impl Primitive3d for Sphere {}
 
 impl Default for Sphere {
@@ -105,6 +106,7 @@ pub struct Plane3d {
     /// Half of the width and height of the plane
     pub half_size: Vec2,
 }
+
 impl Primitive3d for Plane3d {}
 
 impl Default for Plane3d {
@@ -175,6 +177,7 @@ pub struct InfinitePlane3d {
     /// The normal of the plane. The plane will be placed perpendicular to this direction
     pub normal: Dir3,
 }
+
 impl Primitive3d for InfinitePlane3d {}
 
 impl Default for InfinitePlane3d {
@@ -351,6 +354,7 @@ pub struct Line3d {
     /// The direction of the line
     pub direction: Dir3,
 }
+
 impl Primitive3d for Line3d {}
 
 /// A line segment defined by two endpoints in 3D space.
@@ -370,6 +374,7 @@ pub struct Segment3d {
     /// The endpoints of the line segment.
     pub vertices: [Vec3; 2],
 }
+
 impl Primitive3d for Segment3d {}
 
 impl Segment3d {
@@ -578,6 +583,7 @@ pub struct Polyline3d<const N: usize> {
     #[cfg_attr(feature = "serialize", serde(with = "super::serde::array"))]
     pub vertices: [Vec3; N],
 }
+
 impl<const N: usize> Primitive3d for Polyline3d<N> {}
 
 impl<const N: usize> FromIterator<Vec3> for Polyline3d<N> {
@@ -648,6 +654,7 @@ pub struct Cuboid {
     /// Half of the width, height and depth of the cuboid
     pub half_size: Vec3,
 }
+
 impl Primitive3d for Cuboid {}
 
 impl Default for Cuboid {
@@ -742,6 +749,7 @@ pub struct Cylinder {
     /// The half height of the cylinder
     pub half_height: f32,
 }
+
 impl Primitive3d for Cylinder {}
 
 impl Default for Cylinder {
@@ -820,6 +828,7 @@ pub struct Capsule3d {
     /// Half the height of the capsule, excluding the hemispheres
     pub half_length: f32,
 }
+
 impl Primitive3d for Capsule3d {}
 
 impl Default for Capsule3d {
@@ -890,6 +899,7 @@ pub struct Cone {
     /// The height of the cone
     pub height: f32,
 }
+
 impl Primitive3d for Cone {}
 
 impl Default for Cone {
@@ -974,6 +984,7 @@ pub struct ConicalFrustum {
     /// The height of the frustum
     pub height: f32,
 }
+
 impl Primitive3d for ConicalFrustum {}
 
 impl Default for ConicalFrustum {
@@ -1030,6 +1041,7 @@ pub struct Torus {
     #[doc(alias = "radius_of_revolution")]
     pub major_radius: f32,
 }
+
 impl Primitive3d for Torus {}
 
 impl Default for Torus {
@@ -1326,6 +1338,7 @@ pub struct Tetrahedron {
     /// The vertices of the tetrahedron.
     pub vertices: [Vec3; 4],
 }
+
 impl Primitive3d for Tetrahedron {}
 
 impl Default for Tetrahedron {
@@ -1433,6 +1446,7 @@ pub struct Extrusion<T: Primitive2d> {
     /// Half of the depth of the extrusion
     pub half_depth: f32,
 }
+
 impl<T: Primitive2d> Primitive3d for Extrusion<T> {}
 
 impl<T: Primitive2d> Extrusion<T> {

crates/bevy_math/src/primitives/polygon.rs

@@ -34,6 +34,7 @@ struct SweepLineEvent {
     /// Type of the vertex (left or right)
     endpoint: Endpoint,
 }
+
 impl SweepLineEvent {
     #[cfg_attr(
         not(feature = "alloc"),
@@ -46,17 +47,21 @@ impl SweepLineEvent {
         }
     }
 }
+
 impl PartialEq for SweepLineEvent {
     fn eq(&self, other: &Self) -> bool {
         self.position() == other.position()
     }
 }
+
 impl Eq for SweepLineEvent {}
+
 impl PartialOrd for SweepLineEvent {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         Some(self.cmp(other))
     }
 }
+
 impl Ord for SweepLineEvent {
     fn cmp(&self, other: &Self) -> Ordering {
         xy_order(self.position(), other.position())
@@ -129,11 +134,13 @@ struct Segment {
     left: Vec2,
     right: Vec2,
 }
+
 impl PartialEq for Segment {
     fn eq(&self, other: &Self) -> bool {
         self.edge_index == other.edge_index
     }
 }
+
 impl Eq for Segment {}
 
 impl PartialOrd for Segment {
@@ -141,6 +148,7 @@ impl PartialOrd for Segment {
         Some(self.cmp(other))
     }
 }
+
 impl Ord for Segment {
     fn cmp(&self, other: &Self) -> Ordering {
         self.left

crates/bevy_mesh/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_mesh"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides mesh types for Bevy Engine"
 homepage = "https://bevy.org"
@@ -10,16 +10,16 @@ keywords = ["bevy"]
 
 [dependencies]
 # bevy
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_mikktspace = { path = "../bevy_mikktspace", version = "0.16.0-dev" }
+bevy_mikktspace = { path = "../bevy_mikktspace", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
   "serialize",
 ] }

crates/bevy_mesh/src/index.rs

@@ -163,6 +163,7 @@ impl Iterator for IndicesIter<'_> {
 }
 
 impl<'a> ExactSizeIterator for IndicesIter<'a> {}
+
 impl<'a> FusedIterator for IndicesIter<'a> {}
 
 impl From<&Indices> for IndexFormat {

crates/bevy_mesh/src/morph.rs

@@ -117,6 +117,7 @@ pub struct MorphWeights {
     /// The first mesh primitive assigned to these weights
     first_mesh: Option<Handle<Mesh>>,
 }
+
 impl MorphWeights {
     pub fn new(
         weights: Vec<f32>,
@@ -160,6 +161,7 @@ impl MorphWeights {
 pub struct MeshMorphWeights {
     weights: Vec<f32>,
 }
+
 impl MeshMorphWeights {
     pub fn new(weights: Vec<f32>) -> Result<Self, MorphBuildError> {
         if weights.len() > MAX_MORPH_WEIGHTS {
@@ -198,6 +200,7 @@ pub struct MorphAttributes {
     /// animated, as the `w` component is the sign and cannot be animated.
     pub tangent: Vec3,
 }
+
 impl From<[Vec3; 3]> for MorphAttributes {
     fn from([position, normal, tangent]: [Vec3; 3]) -> Self {
         MorphAttributes {
@@ -207,6 +210,7 @@ impl From<[Vec3; 3]> for MorphAttributes {
         }
     }
 }
+
 impl MorphAttributes {
     /// How many components `MorphAttributes` has.
     ///

crates/bevy_mikktspace/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_mikktspace"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 authors = [
   "Benjamin Wasty <benny.wasty@gmail.com>",

crates/bevy_pbr/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_pbr"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Adds PBR rendering to Bevy Engine"
 homepage = "https://bevy.org"
@@ -31,22 +31,22 @@ meshlet_processor = [
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
+bevy_color = { path = "../bevy_color", version = "0.17.0-dev" }
-bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.16.0-dev" }
+bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.16.0-dev" }
+bevy_diagnostic = { path = "../bevy_diagnostic", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
+bevy_image = { path = "../bevy_image", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_tasks = { path = "../bevy_tasks", version = "0.16.0-dev", optional = true }
+bevy_tasks = { path = "../bevy_tasks", version = "0.17.0-dev", optional = true }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
 ] }
 

crates/bevy_pbr/src/cluster/mod.rs

@@ -535,12 +535,12 @@ pub fn extract_clusters(
             continue;
         }
 
-        let num_entities: usize = clusters
+        let entity_count: usize = clusters
             .clusterable_objects
             .iter()
             .map(|l| l.entities.len())
             .sum();
-        let mut data = Vec::with_capacity(clusters.clusterable_objects.len() + num_entities);
+        let mut data = Vec::with_capacity(clusters.clusterable_objects.len() + entity_count);
         for cluster_objects in &clusters.clusterable_objects {
             data.push(ExtractedClusterableObjectElement::ClusterHeader(
                 cluster_objects.counts,

crates/bevy_pbr/src/light/ambient_light.rs

@@ -48,6 +48,7 @@ impl Default for AmbientLight {
         }
     }
 }
+
 impl AmbientLight {
     pub const NONE: AmbientLight = AmbientLight {
         color: Color::WHITE,

crates/bevy_pbr/src/parallax.rs

@@ -33,6 +33,7 @@ pub enum ParallaxMappingMethod {
         max_steps: u32,
     },
 }
+
 impl ParallaxMappingMethod {
     /// [`ParallaxMappingMethod::Relief`] with a 5 steps, a reasonable default.
     pub const DEFAULT_RELIEF_MAPPING: Self = ParallaxMappingMethod::Relief { max_steps: 5 };

crates/bevy_picking/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bevy_picking"
-version = "0.16.0-dev"
+version = "0.17.0-dev"
 edition = "2024"
 description = "Provides screen picking functionality for Bevy Engine"
 homepage = "https://bevy.org"
@@ -13,20 +13,20 @@ bevy_mesh_picking_backend = ["dep:bevy_mesh", "dep:crossbeam-channel"]
 
 [dependencies]
 # bevy
-bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
+bevy_app = { path = "../bevy_app", version = "0.17.0-dev" }
-bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
+bevy_asset = { path = "../bevy_asset", version = "0.17.0-dev" }
-bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
+bevy_derive = { path = "../bevy_derive", version = "0.17.0-dev" }
-bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.17.0-dev" }
-bevy_input = { path = "../bevy_input", version = "0.16.0-dev" }
+bevy_input = { path = "../bevy_input", version = "0.17.0-dev" }
-bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
+bevy_math = { path = "../bevy_math", version = "0.17.0-dev" }
-bevy_mesh = { path = "../bevy_mesh", version = "0.16.0-dev", optional = true }
+bevy_mesh = { path = "../bevy_mesh", version = "0.17.0-dev", optional = true }
-bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.17.0-dev" }
-bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
+bevy_render = { path = "../bevy_render", version = "0.17.0-dev" }
-bevy_time = { path = "../bevy_time", version = "0.16.0-dev" }
+bevy_time = { path = "../bevy_time", version = "0.17.0-dev" }
-bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
+bevy_transform = { path = "../bevy_transform", version = "0.17.0-dev" }
-bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
+bevy_utils = { path = "../bevy_utils", version = "0.17.0-dev" }
-bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
+bevy_window = { path = "../bevy_window", version = "0.17.0-dev" }
-bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
+bevy_platform = { path = "../bevy_platform", version = "0.17.0-dev", default-features = false, features = [
   "std",
 ] }