Bugbear: Add Mutable Parameter fixes (#9682)

Part of #9366

Adds in fixes for B006 and B008, both relating to mutable parameter lint errors.

Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>

3 files changed, 12 insertions, 5 deletions

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 98dac19a95..ad17123915 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -320,8 +320,8 @@ class PersistEventsStore:
         txn: LoggingTransaction,
         events_and_contexts: List[Tuple[EventBase, EventContext]],
         backfilled: bool,
-        state_delta_for_room: Dict[str, DeltaState] = {},
-        new_forward_extremeties: Dict[str, List[str]] = {},
+        state_delta_for_room: Optional[Dict[str, DeltaState]] = None,
+        new_forward_extremeties: Optional[Dict[str, List[str]]] = None,
     ):
         """Insert some number of room events into the necessary database tables.
 
@@ -342,6 +342,9 @@ class PersistEventsStore:
                 extremities.
 
         """
+        state_delta_for_room = state_delta_for_room or {}
+        new_forward_extremeties = new_forward_extremeties or {}
+
         all_events_and_contexts = events_and_contexts
 
         min_stream_order = events_and_contexts[0][0].internal_metadata.stream_ordering
diff --git a/synapse/storage/databases/main/group_server.py b/synapse/storage/databases/main/group_server.py
index 8f462dfc31..bd7826f4e9 100644
--- a/synapse/storage/databases/main/group_server.py
+++ b/synapse/storage/databases/main/group_server.py
@@ -1171,7 +1171,7 @@ class GroupServerStore(GroupServerWorkerStore):
         user_id: str,
         membership: str,
         is_admin: bool = False,
-        content: JsonDict = {},
+        content: Optional[JsonDict] = None,
         local_attestation: Optional[dict] = None,
         remote_attestation: Optional[dict] = None,
         is_publicised: bool = False,
@@ -1192,6 +1192,8 @@ class GroupServerStore(GroupServerWorkerStore):
             is_publicised: Whether this should be publicised.
         """
 
+        content = content or {}
+
         def _register_user_group_membership_txn(txn, next_id):
             # TODO: Upsert?
             self.db_pool.simple_delete_txn(
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index a7f371732f..93431efe00 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -190,7 +190,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     # FIXME: how should this be cached?
     async def get_filtered_current_state_ids(
-        self, room_id: str, state_filter: StateFilter = StateFilter.all()
+        self, room_id: str, state_filter: Optional[StateFilter] = None
     ) -> StateMap[str]:
         """Get the current state event of a given type for a room based on the
         current_state_events table.  This may not be as up-to-date as the result
@@ -205,7 +205,9 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             Map from type/state_key to event ID.
         """
 
-        where_clause, where_args = state_filter.make_sql_filter_clause()
+        where_clause, where_args = (
+            state_filter or StateFilter.all()
+        ).make_sql_filter_clause()
 
         if not where_clause:
             # We delegate to the cached version