Also notify of join events via another path

synapse/handlers/federation_event.py

@@ -2063,6 +2063,10 @@ class FederationEventHandler:
             event, event_pos, max_stream_token, extra_users=extra_users
         )
 
+        if event.type == EventTypes.Member and event.membership == Membership.JOIN:
+            # TODO retrieve the previous state, and exclude join -> join transitions
+            self._notifier.notify_user_joined_room(event.event_id, event.room_id)
+
     def _sanity_check_event(self, ev: EventBase) -> None:
         """
         Do some early sanity checks of a received event