Merge pull request #5923 from vector-im/johannes/5058_room_data_source_leak

Fix retain cycle in MXKRoomDataSource

Riot/Modules/MatrixKit/Models/Room/MXKRoomDataSource.m

@@ -1075,8 +1075,11 @@ typedef NS_ENUM (NSUInteger, MXKRoomDataSourceError) {
     }
 
     // Register a listener to handle redaction which can affect live and past timelines
+    MXWeakify(self);
     redactionListener = [_timeline listenToEventsOfTypes:@[kMXEventTypeStringRoomRedaction] onEvent:^(MXEvent *redactionEvent, MXTimelineDirection direction, MXRoomState *roomState) {
 
+        MXStrongifyAndReturnIfNil(self);
+
         // Consider only live redaction events
         if (direction == MXTimelineDirectionForwards)
         {