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.

4 files changed, 17 insertions, 13 deletions

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

index 66f5b8d108..f68027aaed 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -615,8 +615,8 @@ class ApplicationServicesHandler:
         )
 
         # Fetch the users who have modified their device list since then.
-        users_with_changed_device_lists = (
-            await self.store.get_users_whose_devices_changed(from_key, to_key=new_key)
+        users_with_changed_device_lists = await self.store.get_all_devices_changed(
+            from_key, to_key=new_key
         )
 
         # Filter out any users the application service is not interested in
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
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py

index c8858b22dd..0b395a104d 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -1528,10 +1528,12 @@ class SyncHandler:
             #
             # If we don't have that info cached then we get all the users that
             # share a room with our user and check if those users have changed.
-            changed_users = self.store.get_cached_device_list_changes(
+            cache_result = self.store.get_cached_device_list_changes(
                 since_token.device_list_key
             )
-            if changed_users is not None:
+            if cache_result.hit:
+                changed_users = cache_result.entities
+
                 result = await self.store.get_rooms_for_users(changed_users)
 
                 for changed_user_id, entries in result.items():
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py

index a0ea719430..3f656ea4f5 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -420,11 +420,11 @@ class TypingWriterHandler(FollowerTypingHandler):
         if last_id == current_id:
             return [], current_id, False
 
-        changed_rooms: Optional[
-            Iterable[str]
-        ] = self._typing_stream_change_cache.get_all_entities_changed(last_id)
+        result = self._typing_stream_change_cache.get_all_entities_changed(last_id)
 
-        if changed_rooms is None:
+        if result.hit:
+            changed_rooms: Iterable[str] = result.entities
+        else:
             changed_rooms = self._room_serials
 
         rows = []