Add back the guard against the user directory stream position not existing. (#9428)

As the comment says, this guard was there for when the
initial user directory update has yet to happen.

1 files changed, 7 insertions, 1 deletions

diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py

index 3a1fe3ed52..63f88eac51 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -707,7 +707,13 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
 
         return {row["room_id"] for row in rows}
 
-    async def get_user_directory_stream_pos(self) -> int:
+    async def get_user_directory_stream_pos(self) -> Optional[int]:
+        """
+        Get the stream ID of the user directory stream.
+
+        Returns:
+            The stream token or None if the initial background update hasn't happened yet.
+        """
         return await self.db_pool.simple_select_one_onecol(
             table="user_directory_stream_pos",
             keyvalues={},