Update docstring to clarify that get_partial_state_events_batch does not just give you completely arbitrary partial-state events. (#14417)

Author: reivilibre

changelog.d/14417.misc

@@ -0,0 +1 @@
+Update docstring to clarify that `get_partial_state_events_batch` does not just give you completely arbitrary partial-state events.

synapse/storage/databases/main/events_worker.py

@@ -2228,7 +2228,15 @@ async def is_partial_state_event(self, event_id: str) -> bool:
         return result is not None
 
     async def get_partial_state_events_batch(self, room_id: str) -> List[str]:
-        """Get a list of events in the given room that have partial state"""
+        """
+        Get a list of events in the given room that:
+        - have partial state; and
+        - are ready to be resynced (because they have no prev_events that are
+          partial-stated)
+
+        See the docstring on `_get_partial_state_events_batch_txn` for more
+        information.
+        """
         return await self.db_pool.runInteraction(
             "get_partial_state_events_batch",
             self._get_partial_state_events_batch_txn,