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Explain Changed, Added are not archetype filters (#11049)
Explain potential footgun.
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@ -525,6 +525,36 @@ all_tuples!(impl_query_filter_tuple, 0, 15, F, S);
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/// are visible only after deferred operations are applied,
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/// typically at the end of the schedule iteration.
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///
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/// # Time complexity
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///
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/// `Added` is not [`ArchetypeFilter`], which practically means that
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/// if query (with `T` component filter) matches million entities,
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/// `Added<T>` filter will iterate over all of them even if none of them were just added.
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///
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/// For example, these two systems are roughly equivalent in terms of performance:
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///
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/// ```
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/// # use bevy_ecs::change_detection::{DetectChanges, Ref};
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/// # use bevy_ecs::entity::Entity;
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/// # use bevy_ecs::query::Added;
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/// # use bevy_ecs::system::Query;
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/// # use bevy_ecs_macros::Component;
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/// # #[derive(Component)]
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/// # struct MyComponent;
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/// # #[derive(Component)]
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/// # struct Transform;
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///
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/// fn system1(q: Query<&MyComponent, Added<Transform>>) {
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/// for item in &q { /* component added */ }
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/// }
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///
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/// fn system2(q: Query<(&MyComponent, Ref<Transform>)>) {
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/// for item in &q {
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/// if item.1.is_added() { /* component added */ }
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/// }
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/// }
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/// ```
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///
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/// # Examples
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///
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/// ```
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@ -699,6 +729,37 @@ impl<T: Component> QueryFilter for Added<T> {
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/// are visible only after deferred operations are applied,
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/// typically at the end of the schedule iteration.
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///
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/// # Time complexity
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///
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/// `Changed` is not [`ArchetypeFilter`], which practically means that
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/// if query (with `T` component filter) matches million entities,
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/// `Changed<T>` filter will iterate over all of them even if none of them were changed.
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///
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/// For example, these two systems are roughly equivalent in terms of performance:
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///
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/// ```
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/// # use bevy_ecs::change_detection::DetectChanges;
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/// # use bevy_ecs::entity::Entity;
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/// # use bevy_ecs::query::Changed;
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/// # use bevy_ecs::system::Query;
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/// # use bevy_ecs::world::Ref;
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/// # use bevy_ecs_macros::Component;
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/// # #[derive(Component)]
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/// # struct MyComponent;
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/// # #[derive(Component)]
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/// # struct Transform;
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///
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/// fn system1(q: Query<&MyComponent, Changed<Transform>>) {
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/// for item in &q { /* component changed */ }
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/// }
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///
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/// fn system2(q: Query<(&MyComponent, Ref<Transform>)>) {
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/// for item in &q {
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/// if item.1.is_changed() { /* component changed */ }
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/// }
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/// }
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/// ```
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///
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/// # Examples
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///
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/// ```
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