1 files changed, 3 insertions, 2 deletions
diff --git a/synapse/storage/databases/state/store.py b/synapse/storage/databases/state/store.py
index 97ec65f757..dfcf89d91c 100644
--- a/synapse/storage/databases/state/store.py
+++ b/synapse/storage/databases/state/store.py
@@ -15,7 +15,7 @@
 
 import logging
 from collections import namedtuple
-from typing import Dict, Iterable, List, Set, Tuple
+from typing import Dict, Iterable, List, Optional, Set, Tuple
 
 from synapse.api.constants import EventTypes
 from synapse.storage._base import SQLBaseStore
@@ -210,7 +210,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         return state_filter.filter_state(state_dict_ids), not missing_types
 
     async def _get_state_for_groups(
-        self, groups: Iterable[int], state_filter: StateFilter = StateFilter.all()
+        self, groups: Iterable[int], state_filter: Optional[StateFilter] = None
     ) -> Dict[int, MutableStateMap[str]]:
         """Gets the state at each of a list of state groups, optionally
         filtering by type/state_key
@@ -223,6 +223,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         Returns:
             Dict of state group to state map.
         """
+        state_filter = state_filter or StateFilter.all()
 
         member_filter, non_member_filter = state_filter.get_member_split()