1 files changed, 6 insertions, 2 deletions
diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 9a6c2fd47a..ed29a0a5e2 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -1648,8 +1648,12 @@ class PersistEventsStore:
         txn.call_after(prefill)
 
     def _store_redaction(self, txn: LoggingTransaction, event: EventBase) -> None:
-        # Invalidate the caches for the redacted event, note that these caches
-        # are also cleared as part of event replication in _invalidate_caches_for_event.
+        """Invalidate the caches for the redacted event.
+
+        Note that these caches are also cleared as part of event replication in
+        _invalidate_caches_for_event.
+        """
+        assert event.redacts is not None
         txn.call_after(self.store._invalidate_get_event_cache, event.redacts)
         txn.call_after(self.store.get_relations_for_event.invalidate, (event.redacts,))
         txn.call_after(self.store.get_applicable_edit.invalidate, (event.redacts,))