fix(base): room::display_name emits a RoomInfoNotableUpdateReasons::DISPLAY_NAME.

This patch updates the `room::display_name` response processor to emits
a `RoomInfoNotableUpdateReasons::DISPLAY_NAME`.

Author: Hywan

crates/matrix-sdk-base/src/response_processors/room/display_name.rs

@@ -13,7 +13,10 @@
 // limitations under the License.
 
 use super::super::Context;
-use crate::{rooms::UpdatedRoomDisplayName, store::BaseStateStore, sync::RoomUpdates};
+use crate::{
+    rooms::UpdatedRoomDisplayName, store::BaseStateStore, sync::RoomUpdates,
+    RoomInfoNotableUpdateReasons,
+};
 
 pub async fn update_for_rooms(
     context: &mut Context,
@@ -31,7 +34,14 @@ pub async fn update_for_rooms(
         // Compute the display name. If it's different, let's register the `RoomInfo` in
         // the `StateChanges`.
         if let Ok(UpdatedRoomDisplayName::New(_)) = room.compute_display_name().await {
-            context.state_changes.room_infos.insert(room.room_id().to_owned(), room.clone_info());
+            let room_id = room.room_id().to_owned();
+
+            context.state_changes.room_infos.insert(room_id.clone(), room.clone_info());
+            context
+                .room_info_notable_updates
+                .entry(room_id)
+                .or_default()
+                .insert(RoomInfoNotableUpdateReasons::DISPLAY_NAME);
         }
     }
 }

crates/matrix-sdk-base/src/rooms/normal.rs

@@ -113,6 +113,15 @@ bitflags! {
 
         /// A membership change happened for the current user.
         const MEMBERSHIP = 0b0001_0000;
+
+        /// The display name has changed.
+        const DISPLAY_NAME = 0b0010_0000;
+    }
+}
+
+impl Default for RoomInfoNotableUpdateReasons {
+    fn default() -> Self {
+        Self::empty()
     }
 }
 
@@ -133,12 +142,6 @@ struct ComputedSummary {
     num_joined_invited_guess: u64,
 }
 
-impl Default for RoomInfoNotableUpdateReasons {
-    fn default() -> Self {
-        Self::empty()
-    }
-}
-
 /// The underlying room data structure collecting state for joined, left and
 /// invited rooms.
 #[derive(Debug, Clone)]

crates/matrix-sdk-base/src/sliding_sync.rs

@@ -1089,6 +1089,42 @@ mod tests {
         assert!(client_room.name().is_none());
     }
 
+    #[async_test]
+    async fn test_display_name_is_cached_and_emits_a_notable_update_reason() {
+        let client = logged_in_base_client(None).await;
+        let user_id = user_id!("@u:e.uk");
+        let room_id = room_id!("!r:e.uk");
+
+        let mut room_info_notable_update = client.room_info_notable_update_receiver();
+
+        let room = room_with_name("Hello World", user_id);
+        let response = response_with_room(room_id, room);
+        client
+            .process_sliding_sync(&response, &(), &RequestedRequiredStates::default())
+            .await
+            .expect("Failed to process sync");
+
+        let room = client.get_room(room_id).expect("No room found");
+        assert_eq!(room.cached_display_name().unwrap().to_string(), "Hello World");
+
+        assert_matches!(
+            room_info_notable_update.recv().await,
+            Ok(RoomInfoNotableUpdate { room_id: received_room_id, reasons }) => {
+                assert_eq!(received_room_id, room_id);
+                // Not the reason we are looking for.
+                assert!(!reasons.contains(RoomInfoNotableUpdateReasons::DISPLAY_NAME));
+            }
+        );
+        assert_matches!(
+            room_info_notable_update.recv().await,
+            Ok(RoomInfoNotableUpdate { room_id: received_room_id, reasons }) => {
+                assert_eq!(received_room_id, room_id);
+                // The reason we are looking for :-].
+                assert!(reasons.contains(RoomInfoNotableUpdateReasons::DISPLAY_NAME));
+            }
+        );
+    }
+
     #[async_test]
     async fn test_display_name_is_persisted_from_sliding_sync() {
         let user_id = user_id!("@u:e.uk");