Return immutable objects for cachedList decorators (#16350)

1 files changed, 4 insertions, 4 deletions

diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py
index fff259f74c..7b503dd697 100644
--- a/synapse/storage/databases/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -191,7 +191,7 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
     )
     async def get_subset_users_in_room_with_profiles(
         self, room_id: str, user_ids: Collection[str]
-    ) -> Dict[str, ProfileInfo]:
+    ) -> Mapping[str, ProfileInfo]:
         """Get a mapping from user ID to profile information for a list of users
         in a given room.
 
@@ -676,7 +676,7 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
     )
     async def _get_rooms_for_users(
         self, user_ids: Collection[str]
-    ) -> Dict[str, FrozenSet[str]]:
+    ) -> Mapping[str, FrozenSet[str]]:
         """A batched version of `get_rooms_for_user`.
 
         Returns:
@@ -881,7 +881,7 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
     )
     async def _get_user_ids_from_membership_event_ids(
         self, event_ids: Iterable[str]
-    ) -> Dict[str, Optional[str]]:
+    ) -> Mapping[str, Optional[str]]:
         """For given set of member event_ids check if they point to a join
         event.
 
@@ -1191,7 +1191,7 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
     )
     async def get_membership_from_event_ids(
         self, member_event_ids: Iterable[str]
-    ) -> Dict[str, Optional[EventIdMembership]]:
+    ) -> Mapping[str, Optional[EventIdMembership]]:
         """Get user_id and membership of a set of event IDs.
 
         Returns: