From 335dcf96a20f31e8145e7b8fe83a103a3817d4fa Mon Sep 17 00:00:00 2001
From: James O'Brien <james.obrien@drafly.net>
Date: Mon, 17 Jun 2024 08:15:30 -0700
Subject: [PATCH] Update observer archetype flags for sparse components
 (#13886)

# Objective

- Fixes #13885

## Solution

- Update the flags correctly on archetype creation

## Testing

- Added `observer_order_insert_remove_sparse` to catch regressions.
---
 crates/bevy_ecs/src/archetype.rs    |  1 +
 crates/bevy_ecs/src/observer/mod.rs | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/crates/bevy_ecs/src/archetype.rs b/crates/bevy_ecs/src/archetype.rs
index 6e6450a98d..be502459d5 100644
--- a/crates/bevy_ecs/src/archetype.rs
+++ b/crates/bevy_ecs/src/archetype.rs
@@ -370,6 +370,7 @@ impl Archetype {
             // SAFETY: We are creating an archetype that includes this component so it must exist
             let info = unsafe { components.get_info_unchecked(component_id) };
             info.update_archetype_flags(&mut flags);
+            observers.update_archetype_flags(component_id, &mut flags);
             archetype_components.insert(
                 component_id,
                 ArchetypeComponentInfo {
diff --git a/crates/bevy_ecs/src/observer/mod.rs b/crates/bevy_ecs/src/observer/mod.rs
index 08e87854c4..b1876afddd 100644
--- a/crates/bevy_ecs/src/observer/mod.rs
+++ b/crates/bevy_ecs/src/observer/mod.rs
@@ -400,6 +400,10 @@ mod tests {
     #[derive(Component)]
     struct C;
 
+    #[derive(Component)]
+    #[component(storage = "SparseSet")]
+    struct S;
+
     #[derive(Event)]
     struct EventA;
 
@@ -444,6 +448,22 @@ mod tests {
         assert_eq!(3, world.resource::<R>().0);
     }
 
+    #[test]
+    fn observer_order_insert_remove_sparse() {
+        let mut world = World::new();
+        world.init_resource::<R>();
+
+        world.observe(|_: Trigger<OnAdd, S>, mut res: ResMut<R>| res.assert_order(0));
+        world.observe(|_: Trigger<OnInsert, S>, mut res: ResMut<R>| res.assert_order(1));
+        world.observe(|_: Trigger<OnRemove, S>, mut res: ResMut<R>| res.assert_order(2));
+
+        let mut entity = world.spawn_empty();
+        entity.insert(S);
+        entity.remove::<S>();
+        entity.flush();
+        assert_eq!(3, world.resource::<R>().0);
+    }
+
     #[test]
     fn observer_order_recursive() {
         let mut world = World::new();