Remove Bundle::register_required_components (#19967)

# Objective

- `Bundle::register_required_components` is not used anywhere, let's
remove it

Author: SkiFire13

crates/bevy_ecs/macros/src/lib.rs

@@ -159,13 +159,6 @@ pub fn derive_bundle(input: TokenStream) -> TokenStream {
             ) {
                 #(<#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
-            ) {
-                #(<#active_field_types as #ecs_path::bundle::Bundle>::register_required_components(components, required_components);)*
-            }
         }
     };
 

crates/bevy_ecs/src/bundle.rs

@@ -207,12 +207,6 @@ pub unsafe trait Bundle: DynamicBundle + Send + Sync + 'static {
 
     /// Gets this [`Bundle`]'s component ids. This will be [`None`] if the component has not been registered.
     fn get_component_ids(components: &Components, ids: &mut impl FnMut(Option<ComponentId>));
-
-    /// Registers components that are required by the components in this [`Bundle`].
-    fn register_required_components(
-        _components: &mut ComponentsRegistrator,
-        _required_components: &mut RequiredComponents,
-    );
 }
 
 /// Creates a [`Bundle`] by taking it from internal storage.
@@ -279,20 +273,6 @@ unsafe impl<C: Component> Bundle for C {
         ids(components.register_component::<C>());
     }
 
-    fn register_required_components(
-        components: &mut ComponentsRegistrator,
-        required_components: &mut RequiredComponents,
-    ) {
-        let component_id = components.register_component::<C>();
-        <C as Component>::register_required_components(
-            component_id,
-            components,
-            required_components,
-            0,
-            &mut Vec::new(),
-        );
-    }
-
     fn get_component_ids(components: &Components, ids: &mut impl FnMut(Option<ComponentId>)) {
         ids(components.get_id(TypeId::of::<C>()));
     }
@@ -347,13 +327,6 @@ macro_rules! tuple_impl {
             fn get_component_ids(components: &Components, ids: &mut impl FnMut(Option<ComponentId>)){
                 $(<$name as Bundle>::get_component_ids(components, ids);)*
             }
-
-            fn register_required_components(
-                components: &mut ComponentsRegistrator,
-                required_components: &mut RequiredComponents,
-            ) {
-                $(<$name as Bundle>::register_required_components(components, required_components);)*
-            }
         }
 
         #[expect(

crates/bevy_ecs/src/spawn.rs

@@ -199,16 +199,6 @@ unsafe impl<R: Relationship, L: SpawnableList<R> + Send + Sync + 'static> Bundle
     ) {
         <R::RelationshipTarget as Bundle>::get_component_ids(components, ids);
     }
-
-    fn register_required_components(
-        components: &mut crate::component::ComponentsRegistrator,
-        required_components: &mut crate::component::RequiredComponents,
-    ) {
-        <R::RelationshipTarget as Bundle>::register_required_components(
-            components,
-            required_components,
-        );
-    }
 }
 
 impl<R: Relationship, L: SpawnableList<R>> DynamicBundle for SpawnRelatedBundle<R, L> {
@@ -267,16 +257,6 @@ unsafe impl<R: Relationship, B: Bundle> Bundle for SpawnOneRelated<R, B> {
     ) {
         <R::RelationshipTarget as Bundle>::get_component_ids(components, ids);
     }
-
-    fn register_required_components(
-        components: &mut crate::component::ComponentsRegistrator,
-        required_components: &mut crate::component::RequiredComponents,
-    ) {
-        <R::RelationshipTarget as Bundle>::register_required_components(
-            components,
-            required_components,
-        );
-    }
 }
 
 /// [`RelationshipTarget`] methods that create a [`Bundle`] with a [`DynamicBundle::Effect`] that:

release-content/migration-guides/remove_bundle_register_required_components.md

@@ -0,0 +1,6 @@
+---
+title: Remove Bundle::register_required_components
+pull_requests: [19967]
+---
+
+This method was effectively dead-code as it was never used by the ECS to compute required components, hence it was removed. if you were overriding its implementation you can just remove it, as it never did anything. If you were using it in any other way, please open an issue.