Remove the need to derive Event when deriving EntityEvent (#20104)

tim-blackbird · web-flow · commit 57086d4416ac · 2025-07-15T16:45:38.000Z
# Objective Since we are planning to remove the need to derive both `Event` and `EntityEvent` in 0.17 either way, I'm choosing to do the easy thing in this PR so we can get the churn out of the way early. Context from [discord](https://discordapp.com/channels/691052431525675048/1383928409784193024/1393463673137401946). Related to, and will conflict slightly with #20101. ## Solution - Derive `Event` as part of the `EntityEvent` derive - Remove any `Event` derives that were made unnecessary - Update release notes
diff --git a/benches/benches/bevy_ecs/observers/propagation.rs b/benches/benches/bevy_ecs/observers/propagation.rs
@@ -61,7 +61,7 @@ pub fn event_propagation(criterion: &mut Criterion) {
     group.finish();
 }
 
-#[derive(Event, EntityEvent, Clone, Component)]
+#[derive(EntityEvent, Clone, Component)]
 #[entity_event(traversal = &'static ChildOf, auto_propagate)]
 struct TestEvent<const N: usize> {}
 
diff --git a/benches/benches/bevy_ecs/observers/simple.rs b/benches/benches/bevy_ecs/observers/simple.rs
@@ -1,7 +1,7 @@
 use core::hint::black_box;
 
 use bevy_ecs::{
-    event::{EntityEvent, Event},
+    event::EntityEvent,
     observer::{On, TriggerTargets},
     world::World,
 };
@@ -13,7 +13,7 @@ fn deterministic_rand() -> ChaCha8Rng {
     ChaCha8Rng::seed_from_u64(42)
 }
 
-#[derive(Clone, Event, EntityEvent)]
+#[derive(Clone, EntityEvent)]
 struct EventBase;
 
 pub fn observe_simple(criterion: &mut Criterion) {
diff --git a/crates/bevy_animation/src/lib.rs b/crates/bevy_animation/src/lib.rs
@@ -1534,7 +1534,7 @@ mod tests {
 
     use super::*;
 
-    #[derive(Event, EntityEvent, Reflect, Clone)]
+    #[derive(EntityEvent, Reflect, Clone)]
     struct A;
 
     #[track_caller]
diff --git a/crates/bevy_app/src/app.rs b/crates/bevy_app/src/app.rs
@@ -1325,7 +1325,7 @@ impl App {
     /// #   friends_allowed: bool,
     /// # };
     /// #
-    /// # #[derive(Event, EntityEvent)]
+    /// # #[derive(EntityEvent)]
     /// # struct Invite;
     /// #
     /// # #[derive(Component)]
diff --git a/crates/bevy_core_widgets/src/core_checkbox.rs b/crates/bevy_core_widgets/src/core_checkbox.rs
@@ -1,7 +1,7 @@
 use accesskit::Role;
 use bevy_a11y::AccessibilityNode;
 use bevy_app::{App, Plugin};
-use bevy_ecs::event::{EntityEvent, Event};
+use bevy_ecs::event::EntityEvent;
 use bevy_ecs::query::{Has, Without};
 use bevy_ecs::system::{In, ResMut};
 use bevy_ecs::{
@@ -97,7 +97,7 @@ fn checkbox_on_pointer_click(
 ///     commands.trigger_targets(SetChecked(true), checkbox);
 /// }
 /// ```
-#[derive(Event, EntityEvent)]
+#[derive(EntityEvent)]
 pub struct SetChecked(pub bool);
 
 /// Event which can be triggered on a checkbox to toggle the checked state. This can be used to
@@ -119,7 +119,7 @@ pub struct SetChecked(pub bool);
 ///     commands.trigger_targets(ToggleChecked, checkbox);
 /// }
 /// ```
-#[derive(Event, EntityEvent)]
+#[derive(EntityEvent)]
 pub struct ToggleChecked;
 
 fn checkbox_on_set_checked(
diff --git a/crates/bevy_core_widgets/src/core_slider.rs b/crates/bevy_core_widgets/src/core_slider.rs
@@ -3,7 +3,7 @@ use core::ops::RangeInclusive;
 use accesskit::{Orientation, Role};
 use bevy_a11y::AccessibilityNode;
 use bevy_app::{App, Plugin};
-use bevy_ecs::event::{EntityEvent, Event};
+use bevy_ecs::event::EntityEvent;
 use bevy_ecs::hierarchy::Children;
 use bevy_ecs::lifecycle::Insert;
 use bevy_ecs::query::Has;
@@ -498,7 +498,7 @@ pub(crate) fn slider_on_insert_step(trigger: On<Insert, SliderStep>, mut world:
 ///     commands.trigger_targets(SetSliderValue::Relative(-0.25), slider);
 /// }
 /// ```
-#[derive(Event, EntityEvent, Clone)]
+#[derive(EntityEvent, Clone)]
 pub enum SetSliderValue {
     /// Set the slider value to a specific value.
     Absolute(f32),
diff --git a/crates/bevy_ecs/README.md b/crates/bevy_ecs/README.md
@@ -333,7 +333,7 @@ If the event is an `EntityEvent`, it can also be triggered to target specific en
 ```rust
 use bevy_ecs::prelude::*;
 
-#[derive(Event, EntityEvent)]
+#[derive(EntityEvent)]
 struct Explode;
 
 let mut world = World::new();
diff --git a/crates/bevy_ecs/macros/src/component.rs b/crates/bevy_ecs/macros/src/component.rs
@@ -73,6 +73,7 @@ pub fn derive_entity_event(input: TokenStream) -> TokenStream {
     let (impl_generics, type_generics, where_clause) = &ast.generics.split_for_impl();
 
     TokenStream::from(quote! {
+        impl #impl_generics #bevy_ecs_path::event::Event for #struct_name #type_generics #where_clause {}
         impl #impl_generics #bevy_ecs_path::event::EntityEvent for #struct_name #type_generics #where_clause {
             type Traversal = #traversal;
             const AUTO_PROPAGATE: bool = #auto_propagate;
diff --git a/crates/bevy_ecs/macros/src/lib.rs b/crates/bevy_ecs/macros/src/lib.rs
@@ -557,7 +557,7 @@ pub fn derive_event(input: TokenStream) -> TokenStream {
 /// see full explanation on `EntityEvent` trait docs.
 ///
 /// ```ignore
-/// #[derive(Event, EntityEvent)]
+/// #[derive(EntityEvent)]
 /// /// Traversal component
 /// #[entity_event(traversal = &'static ChildOf)]
 /// /// Always propagate
diff --git a/crates/bevy_ecs/src/event/base.rs b/crates/bevy_ecs/src/event/base.rs
@@ -150,7 +150,7 @@ pub trait Event: Send + Sync + 'static {
 /// # use bevy_ecs::prelude::*;
 /// #
 /// // When the `Damage` event is triggered on an entity, bubble the event up to ancestors.
-/// #[derive(Event, EntityEvent)]
+/// #[derive(EntityEvent)]
 /// #[entity_event(traversal = &'static ChildOf, auto_propagate)]
 /// struct Damage {
 ///     amount: f32,
@@ -162,7 +162,7 @@ pub trait Event: Send + Sync + 'static {
 /// ```
 /// # use bevy_ecs::prelude::*;
 /// #
-/// # #[derive(Event, EntityEvent)]
+/// # #[derive(EntityEvent)]
 /// # #[entity_event(traversal = &'static ChildOf, auto_propagate)]
 /// # struct Damage {
 /// #     amount: f32,
@@ -201,7 +201,7 @@ pub trait Event: Send + Sync + 'static {
 /// ```
 /// # use bevy_ecs::prelude::*;
 /// #
-/// # #[derive(Event, EntityEvent)]
+/// # #[derive(EntityEvent)]
 /// # #[entity_event(traversal = &'static ChildOf, auto_propagate)]
 /// # struct Damage {
 /// #     amount: f32,
@@ -242,7 +242,7 @@ pub trait Event: Send + Sync + 'static {
 #[diagnostic::on_unimplemented(
     message = "`{Self}` is not an `EntityEvent`",
     label = "invalid `EntityEvent`",
-    note = "consider annotating `{Self}` with `#[derive(Event, EntityEvent)]`"
+    note = "consider annotating `{Self}` with `#[derive(EntityEvent)]`"
 )]
 pub trait EntityEvent: Event {
     /// The component that describes which [`Entity`] to propagate this event to next, when [propagation] is enabled.
diff --git a/crates/bevy_ecs/src/lifecycle.rs b/crates/bevy_ecs/src/lifecycle.rs
@@ -54,8 +54,8 @@ use crate::{
     component::{Component, ComponentId, ComponentIdFor, Tick},
     entity::Entity,
     event::{
-        BufferedEvent, EntityEvent, Event, EventCursor, EventId, EventIterator,
-        EventIteratorWithId, EventKey, Events,
+        BufferedEvent, EntityEvent, EventCursor, EventId, EventIterator, EventIteratorWithId,
+        EventKey, Events,
     },
     query::FilteredAccessSet,
     relationship::RelationshipHookMode,
@@ -328,7 +328,7 @@ pub const DESPAWN: EventKey = EventKey(ComponentId::new(4));
 /// Trigger emitted when a component is inserted onto an entity that does not already have that
 /// component. Runs before `Insert`.
 /// See [`crate::lifecycle::ComponentHooks::on_add`] for more information.
-#[derive(Event, EntityEvent, Debug, Clone)]
+#[derive(EntityEvent, Debug, Clone)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 #[cfg_attr(feature = "bevy_reflect", reflect(Debug))]
 #[doc(alias = "OnAdd")]
@@ -337,7 +337,7 @@ pub struct Add;
 /// Trigger emitted when a component is inserted, regardless of whether or not the entity already
 /// had that component. Runs after `Add`, if it ran.
 /// See [`crate::lifecycle::ComponentHooks::on_insert`] for more information.
-#[derive(Event, EntityEvent, Debug, Clone)]
+#[derive(EntityEvent, Debug, Clone)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 #[cfg_attr(feature = "bevy_reflect", reflect(Debug))]
 #[doc(alias = "OnInsert")]
@@ -348,7 +348,7 @@ pub struct Insert;
 ///
 /// Runs before the value is replaced, so you can still access the original component data.
 /// See [`crate::lifecycle::ComponentHooks::on_replace`] for more information.
-#[derive(Event, EntityEvent, Debug, Clone)]
+#[derive(EntityEvent, Debug, Clone)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 #[cfg_attr(feature = "bevy_reflect", reflect(Debug))]
 #[doc(alias = "OnReplace")]
@@ -357,15 +357,15 @@ pub struct Replace;
 /// Trigger emitted when a component is removed from an entity, and runs before the component is
 /// removed, so you can still access the component data.
 /// See [`crate::lifecycle::ComponentHooks::on_remove`] for more information.
-#[derive(Event, EntityEvent, Debug, Clone)]
+#[derive(EntityEvent, Debug, Clone)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 #[cfg_attr(feature = "bevy_reflect", reflect(Debug))]
 #[doc(alias = "OnRemove")]
 pub struct Remove;
 
 /// Trigger emitted for each component on an entity when it is despawned.
 /// See [`crate::lifecycle::ComponentHooks::on_despawn`] for more information.
-#[derive(Event, EntityEvent, Debug, Clone)]
+#[derive(EntityEvent, Debug, Clone)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect))]
 #[cfg_attr(feature = "bevy_reflect", reflect(Debug))]
 #[doc(alias = "OnDespawn")]
diff --git a/crates/bevy_ecs/src/observer/distributed_storage.rs b/crates/bevy_ecs/src/observer/distributed_storage.rs
@@ -131,7 +131,7 @@ use crate::prelude::ReflectComponent;
 /// # use bevy_ecs::prelude::*;
 /// # let mut world = World::default();
 /// # let entity = world.spawn_empty().id();
-/// #[derive(Event, EntityEvent)]
+/// #[derive(EntityEvent)]
 /// struct Explode;
 ///
 /// world.add_observer(|trigger: On<Explode>, mut commands: Commands| {
@@ -151,7 +151,7 @@ use crate::prelude::ReflectComponent;
 /// # let mut world = World::default();
 /// # let e1 = world.spawn_empty().id();
 /// # let e2 = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
+/// # #[derive(EntityEvent)]
 /// # struct Explode;
 /// world.trigger_targets(Explode, [e1, e2]);
 /// ```
@@ -165,7 +165,7 @@ use crate::prelude::ReflectComponent;
 /// # let mut world = World::default();
 /// # let e1 = world.spawn_empty().id();
 /// # let e2 = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
+/// # #[derive(EntityEvent)]
 /// # struct Explode;
 /// world.entity_mut(e1).observe(|trigger: On<Explode>, mut commands: Commands| {
 ///     println!("Boom!");
@@ -187,7 +187,7 @@ use crate::prelude::ReflectComponent;
 /// # use bevy_ecs::prelude::*;
 /// # let mut world = World::default();
 /// # let entity = world.spawn_empty().id();
-/// # #[derive(Event, EntityEvent)]
+/// # #[derive(EntityEvent)]
 /// # struct Explode;
 /// let mut observer = Observer::new(|trigger: On<Explode>| {});
 /// observer.watch_entity(entity);
diff --git a/crates/bevy_ecs/src/observer/entity_cloning.rs b/crates/bevy_ecs/src/observer/entity_cloning.rs
@@ -72,18 +72,14 @@ fn component_clone_observed_by(_source: &SourceComponent, ctx: &mut ComponentClo
 #[cfg(test)]
 mod tests {
     use crate::{
-        entity::EntityCloner,
-        event::{EntityEvent, Event},
-        observer::On,
-        resource::Resource,
-        system::ResMut,
+        entity::EntityCloner, event::EntityEvent, observer::On, resource::Resource, system::ResMut,
         world::World,
     };
 
     #[derive(Resource, Default)]
     struct Num(usize);
 
-    #[derive(Event, EntityEvent)]
+    #[derive(EntityEvent)]
     struct E;
 
     #[test]
diff --git a/crates/bevy_ecs/src/observer/mod.rs b/crates/bevy_ecs/src/observer/mod.rs
@@ -521,10 +521,10 @@ mod tests {
     #[component(storage = "SparseSet")]
     struct S;
 
-    #[derive(Event, EntityEvent)]
+    #[derive(EntityEvent)]
     struct EventA;
 
-    #[derive(Event, EntityEvent)]
+    #[derive(EntityEvent)]
     struct EventWithData {
         counter: usize,
     }
@@ -548,7 +548,7 @@ mod tests {
         }
     }
 
-    #[derive(Component, Event, EntityEvent)]
+    #[derive(Component, EntityEvent)]
     #[entity_event(traversal = &'static ChildOf, auto_propagate)]
     struct EventPropagating;
 
diff --git a/crates/bevy_ecs/src/observer/system_param.rs b/crates/bevy_ecs/src/observer/system_param.rs
@@ -83,7 +83,7 @@ impl<'w, E, B: Bundle> On<'w, E, B> {
     /// ```rust
     /// # use bevy_ecs::prelude::*;
     ///
-    /// #[derive(Event, EntityEvent)]  
+    /// #[derive(EntityEvent)]  
     /// struct AssertEvent;  
     ///
     /// fn assert_observer(trigger: On<AssertEvent>) {  
diff --git a/crates/bevy_ecs/src/world/entity_ref.rs b/crates/bevy_ecs/src/world/entity_ref.rs
@@ -5861,7 +5861,7 @@ mod tests {
         assert_eq!((&mut X(8), &mut Y(9)), (x_component, y_component));
     }
 
-    #[derive(Event, EntityEvent)]
+    #[derive(EntityEvent)]
     struct TestEvent;
 
     #[test]
diff --git a/crates/bevy_input_focus/src/lib.rs b/crates/bevy_input_focus/src/lib.rs
@@ -137,7 +137,7 @@ pub struct InputFocusVisible(pub bool);
 ///
 /// To set up your own bubbling input event, add the [`dispatch_focused_input::<MyEvent>`](dispatch_focused_input) system to your app,
 /// in the [`InputFocusSystems::Dispatch`] system set during [`PreUpdate`].
-#[derive(Event, EntityEvent, Clone, Debug, Component)]
+#[derive(EntityEvent, Clone, Debug, Component)]
 #[entity_event(traversal = WindowTraversal, auto_propagate)]
 #[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Component, Clone))]
 pub struct FocusedInput<E: BufferedEvent + Clone> {
@@ -149,7 +149,7 @@ pub struct FocusedInput<E: BufferedEvent + Clone> {
 
 /// 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)]
+#[derive(Clone, EntityEvent)]
 #[entity_event(traversal = WindowTraversal, auto_propagate)]
 pub struct AcquireFocus {
     /// The primary window entity.
diff --git a/crates/bevy_picking/src/events.rs b/crates/bevy_picking/src/events.rs
@@ -59,7 +59,7 @@ use crate::{
 ///
 /// The documentation for the [`pointer_events`] explains the events this module exposes and
 /// the order in which they fire.
-#[derive(Event, BufferedEvent, EntityEvent, Clone, PartialEq, Debug, Reflect, Component)]
+#[derive(BufferedEvent, EntityEvent, Clone, PartialEq, Debug, Reflect, Component)]
 #[entity_event(traversal = PointerTraversal, auto_propagate)]
 #[reflect(Component, Debug, Clone)]
 pub struct Pointer<E: Debug + Clone + Reflect> {
diff --git a/crates/bevy_render/src/gpu_readback.rs b/crates/bevy_render/src/gpu_readback.rs
@@ -15,14 +15,14 @@ use async_channel::{Receiver, Sender};
 use bevy_app::{App, Plugin};
 use bevy_asset::Handle;
 use bevy_derive::{Deref, DerefMut};
+use bevy_ecs::schedule::IntoScheduleConfigs;
 use bevy_ecs::{
     change_detection::ResMut,
     entity::Entity,
     event::EntityEvent,
     prelude::{Component, Resource, World},
     system::{Query, Res},
 };
-use bevy_ecs::{event::Event, schedule::IntoScheduleConfigs};
 use bevy_image::{Image, TextureFormatPixelInfo};
 use bevy_platform::collections::HashMap;
 use bevy_reflect::Reflect;
@@ -111,7 +111,7 @@ impl Readback {
 ///
 /// The event contains the data as a `Vec<u8>`, which can be interpreted as the raw bytes of the
 /// requested buffer or texture.
-#[derive(Event, EntityEvent, Deref, DerefMut, Reflect, Debug)]
+#[derive(EntityEvent, Deref, DerefMut, Reflect, Debug)]
 #[reflect(Debug)]
 pub struct ReadbackComplete(pub Vec<u8>);
 
diff --git a/crates/bevy_render/src/view/window/screenshot.rs b/crates/bevy_render/src/view/window/screenshot.rs
@@ -40,7 +40,7 @@ use std::{
 use tracing::{error, info, warn};
 use wgpu::{CommandEncoder, Extent3d, TextureFormat};
 
-#[derive(Event, EntityEvent, Deref, DerefMut, Reflect, Debug)]
+#[derive(EntityEvent, Deref, DerefMut, Reflect, Debug)]
 #[reflect(Debug)]
 pub struct ScreenshotCaptured(pub Image);
 
diff --git a/crates/bevy_scene/src/scene_spawner.rs b/crates/bevy_scene/src/scene_spawner.rs
@@ -2,7 +2,7 @@ use crate::{DynamicScene, Scene};
 use bevy_asset::{AssetEvent, AssetId, Assets, Handle};
 use bevy_ecs::{
     entity::{Entity, EntityHashMap},
-    event::{EntityEvent, Event, EventCursor, Events},
+    event::{EntityEvent, EventCursor, Events},
     hierarchy::ChildOf,
     reflect::AppTypeRegistry,
     resource::Resource,
@@ -21,12 +21,13 @@ use bevy_ecs::{
     prelude::{Changed, Component, Without},
     system::{Commands, Query},
 };
+
 /// Triggered on a scene's parent entity when [`crate::SceneInstance`] becomes ready to use.
 ///
 /// See also [`On`], [`SceneSpawner::instance_is_ready`].
 ///
 /// [`On`]: bevy_ecs::observer::On
-#[derive(Clone, Copy, Debug, Eq, PartialEq, Event, EntityEvent, Reflect)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq, EntityEvent, Reflect)]
 #[reflect(Debug, PartialEq, Clone)]
 pub struct SceneInstanceReady {
     /// Instance which has been spawned.
diff --git a/examples/animation/animated_mesh_events.rs b/examples/animation/animated_mesh_events.rs
@@ -37,7 +37,7 @@ struct Animations {
     graph_handle: Handle<AnimationGraph>,
 }
 
-#[derive(Event, EntityEvent, Reflect, Clone)]
+#[derive(EntityEvent, Reflect, Clone)]
 struct OnStep;
 
 fn observe_on_step(
diff --git a/examples/animation/animation_events.rs b/examples/animation/animation_events.rs
diff --git a/examples/ecs/observer_propagation.rs b/examples/ecs/observer_propagation.rs
diff --git a/examples/ecs/observers.rs b/examples/ecs/observers.rs
diff --git a/examples/no_std/library/src/lib.rs b/examples/no_std/library/src/lib.rs
diff --git a/examples/ui/scroll.rs b/examples/ui/scroll.rs
diff --git a/release-content/release-notes/event_split.md b/release-content/release-notes/event_split.md

Original file line number	Diff line number	Diff line change
`@@ -61,7 +61,7 @@ pub fn event_propagation(criterion: &mut Criterion) {`
`61`	`61`	`group.finish();`
`62`	`62`	`}`
`63`	`63`
`64`		`-#[derive(Event, EntityEvent, Clone, Component)]`
	`64`	`+#[derive(EntityEvent, Clone, Component)]`
`65`	`65`	`#[entity_event(traversal = &'static ChildOf, auto_propagate)]`
`66`	`66`	`struct TestEvent<const N: usize> {}`
`67`	`67`