Merge branch 'develop' into madlittlemods/return-historical-events-in-order-from-backfill

Conflicts:
	scripts-dev/complement.sh
	synapse/handlers/room_batch.py

1 files changed, 5 insertions, 0 deletions

diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py

index d7527008c4..f251402ed8 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -322,6 +322,11 @@ class _AsyncEventContextImpl(EventContext):
         attributes by loading from the database.
         """
         if self.state_group is None:
+            # No state group means the event is an outlier. Usually the state_ids dicts are also
+            # pre-set to empty dicts, but they get reset when the context is serialized, so set
+            # them to empty dicts again here.
+            self._current_state_ids = {}
+            self._prev_state_ids = {}
             return
 
         current_state_ids = await self._storage.state.get_state_ids_for_group(