Stop get_joined_users corruption from custom statuses

Fix a bug where the `get_joined_users` cache could be corrupted by custom status events (or other state events with a state_key matching the user ID). Fixes: #7099.
matrix-org · Apr 30, 2020 · e723ce3 · e723ce3
1 parent 204664d
commit e723ce3
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diff --git a/changelog.d/7376.bugfix b/changelog.d/7376.bugfix
@@ -0,0 +1 @@
+Fix a bug which could cause messages not to be sent over federation, when state events with state keys matching user IDs (such as custom user statuses) were received statuses.
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
@@ -576,7 +576,8 @@ def _get_joined_users_from_context(
                         if key[0] == EventTypes.Member
                     ]
                     for etype, state_key in context.delta_ids:
-                        users_in_room.pop(state_key, None)
+                        if etype == EventTypes.Member:
+                            users_in_room.pop(state_key, None)
 
         # We check if we have any of the member event ids in the event cache
         # before we ask the DB