Faster joins: Omit device list updates from partial state rooms in /s…

…ync (#15069) ...when lazy loading of members is not enabled. It's weird to notify a client that another user's device list has changed when the client doesn't think that they share a room. Note that when a room is un-partial stated, device list updates are emitted for every member in that room over /sync. Signed-off-by: Sean Quah <[email protected]>
matrix-org · Feb 14, 2023 · 463c19a · 463c19a
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commit 463c19a
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diff --git a/changelog.d/15069.misc b/changelog.d/15069.misc
@@ -0,0 +1 @@
+Faster joins: omit device list updates originating from partial state rooms in /sync responses without lazy loading of members enabled.
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
@@ -1399,6 +1399,11 @@ async def generate_sync_result(
                 for room_id, is_partial_state in results.items()
                 if is_partial_state
             )
+            membership_change_events = [
+                event
+                for event in membership_change_events
+                if not results.get(event.room_id, False)
+            ]
 
         # Incremental eager syncs should additionally include rooms that
         # - we are joined to