Resync state after partial-state join (#12394)

We work through all the events with partial state, updating the state at each
of them. Once it's done, we recalculate the state for the whole room, and then
mark the room as having complete state.

synapse/storage/databases/main/events.py

@@ -963,6 +963,21 @@ class PersistEventsStore:
                 values=to_insert,
             )
 
+    async def update_current_state(
+        self,
+        room_id: str,
+        state_delta: DeltaState,
+        stream_id: int,
+    ) -> None:
+        """Update the current state stored in the datatabase for the given room"""
+
+        await self.db_pool.runInteraction(
+            "update_current_state",
+            self._update_current_state_txn,
+            state_delta_by_room={room_id: state_delta},
+            stream_id=stream_id,
+        )
+
     def _update_current_state_txn(
         self,
         txn: LoggingTransaction,