Minor typing fixes for `synapse/storage/persist_events.py` (#12069)

Signed-off-by: Sean Quah <seanq@element.io>

1 files changed, 12 insertions, 13 deletions

diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index 428d66a617..7d543fdbe0 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -427,21 +427,21 @@ class EventsPersistenceStorage:
             # NB: Assumes that we are only persisting events for one room
             # at a time.
 
-            # map room_id->list[event_ids] giving the new forward
+            # map room_id->set[event_ids] giving the new forward
             # extremities in each room
-            new_forward_extremeties = {}
+            new_forward_extremities: Dict[str, Set[str]] = {}
 
             # map room_id->(type,state_key)->event_id tracking the full
             # state in each room after adding these events.
             # This is simply used to prefill the get_current_state_ids
             # cache
-            current_state_for_room = {}
+            current_state_for_room: Dict[str, StateMap[str]] = {}
 
             # map room_id->(to_delete, to_insert) where to_delete is a list
             # of type/state keys to remove from current state, and to_insert
             # is a map (type,key)->event_id giving the state delta in each
             # room
-            state_delta_for_room = {}
+            state_delta_for_room: Dict[str, DeltaState] = {}
 
             # Set of remote users which were in rooms the server has left. We
             # should check if we still share any rooms and if not we mark their
@@ -460,14 +460,13 @@ class EventsPersistenceStorage:
                         )
 
                     for room_id, ev_ctx_rm in events_by_room.items():
-                        latest_event_ids = (
+                        latest_event_ids = set(
                             await self.main_store.get_latest_event_ids_in_room(room_id)
                         )
                         new_latest_event_ids = await self._calculate_new_extremities(
                             room_id, ev_ctx_rm, latest_event_ids
                         )
 
-                        latest_event_ids = set(latest_event_ids)
                         if new_latest_event_ids == latest_event_ids:
                             # No change in extremities, so no change in state
                             continue
@@ -478,7 +477,7 @@ class EventsPersistenceStorage:
                         # extremities, so we'll `continue` above and skip this bit.)
                         assert new_latest_event_ids, "No forward extremities left!"
 
-                        new_forward_extremeties[room_id] = new_latest_event_ids
+                        new_forward_extremities[room_id] = new_latest_event_ids
 
                         len_1 = (
                             len(latest_event_ids) == 1
@@ -533,7 +532,7 @@ class EventsPersistenceStorage:
                             # extremities, so we'll `continue` above and skip this bit.)
                             assert new_latest_event_ids, "No forward extremities left!"
 
-                            new_forward_extremeties[room_id] = new_latest_event_ids
+                            new_forward_extremities[room_id] = new_latest_event_ids
 
                         # If either are not None then there has been a change,
                         # and we need to work out the delta (or use that
@@ -567,7 +566,7 @@ class EventsPersistenceStorage:
                             )
                             if not is_still_joined:
                                 logger.info("Server no longer in room %s", room_id)
-                                latest_event_ids = []
+                                latest_event_ids = set()
                                 current_state = {}
                                 delta.no_longer_in_room = True
 
@@ -582,7 +581,7 @@ class EventsPersistenceStorage:
                 chunk,
                 current_state_for_room=current_state_for_room,
                 state_delta_for_room=state_delta_for_room,
-                new_forward_extremeties=new_forward_extremeties,
+                new_forward_extremities=new_forward_extremities,
                 use_negative_stream_ordering=backfilled,
                 inhibit_local_membership_updates=backfilled,
             )
@@ -596,7 +595,7 @@ class EventsPersistenceStorage:
         room_id: str,
         event_contexts: List[Tuple[EventBase, EventContext]],
         latest_event_ids: Collection[str],
-    ):
+    ) -> Set[str]:
         """Calculates the new forward extremities for a room given events to
         persist.
 
@@ -906,9 +905,9 @@ class EventsPersistenceStorage:
             # Ideally we'd figure out a way of still being able to drop old
             # dummy events that reference local events, but this is good enough
             # as a first cut.
-            events_to_check = [event]
+            events_to_check: Collection[EventBase] = [event]
             while events_to_check:
-                new_events = set()
+                new_events: Set[str] = set()
                 for event_to_check in events_to_check:
                     if self.is_mine_id(event_to_check.sender):
                         if event_to_check.type != EventTypes.Dummy: