Default to `public` join rule in remote summary (#18493)

See: https://github.com/element-hq/synapse/issues/18358#issuecomment-2866119550

1 files changed, 1 insertions, 1 deletions

diff --git a/synapse/handlers/room_summary.py b/synapse/handlers/room_summary.py

index 64f5bea014..91b131d09b 100644
--- a/synapse/handlers/room_summary.py
+++ b/synapse/handlers/room_summary.py
@@ -701,7 +701,7 @@ class RoomSummaryHandler:
         # The API doesn't return the room version so assume that a
         # join rule of knock is valid.
         if (
-            room.get("join_rule")
+            room.get("join_rule", JoinRules.PUBLIC)
             in (JoinRules.PUBLIC, JoinRules.KNOCK, JoinRules.KNOCK_RESTRICTED)
             or room.get("world_readable") is True
         ):