Changelog

changelog.d/12712.bugfix

@@ -0,0 +1 @@
+Fix a bug introduced in Synapse 1.38.0 where empty rooms would be created automatically if an MAU limit was set and time-based cache expiry was turned on.

synapse/server_notices/server_notices_manager.py

@@ -90,7 +90,7 @@ class ServerNoticesManager:
         )
         return event
 
-    @cached()
+    @cached(prune_unread_entries=False)
     async def get_or_create_notice_room_for_user(self, user_id: str) -> str:
         """Get the room for notices for a given user