Better return type for `get_all_entities_changed` (#14604)

Help callers from using the return value incorrectly by ensuring
that callers explicitly check if there was a cache hit or not.

1 files changed, 7 insertions, 5 deletions

diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 1799174c2f..2af90b25a3 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -1692,10 +1692,12 @@ class PresenceEventSource(EventSource[int, UserPresenceState]):
 
             if from_key is not None:
                 # First get all users that have had a presence update
-                updated_users = stream_change_cache.get_all_entities_changed(from_key)
+                result = stream_change_cache.get_all_entities_changed(from_key)
 
                 # Cross-reference users we're interested in with those that have had updates.
-                if updated_users is not None:
+                if result.hit:
+                    updated_users = result.entities
+
                     # If we have the full list of changes for presence we can
                     # simply check which ones share a room with the user.
                     get_updates_counter.labels("stream").inc()
@@ -1767,9 +1769,9 @@ class PresenceEventSource(EventSource[int, UserPresenceState]):
         updated_users = None
         if from_key:
             # Only return updates since the last sync
-            updated_users = self.store.presence_stream_cache.get_all_entities_changed(
-                from_key
-            )
+            result = self.store.presence_stream_cache.get_all_entities_changed(from_key)
+            if result.hit:
+                updated_users = result.entities
 
         if updated_users is not None:
             # Get the actual presence update for each change