hacks to work around #6605

synapse/state/v2.py

@@ -183,16 +183,16 @@ def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
 
     pl = None
     for aid in event.auth_event_ids():
-        aev = yield _get_event(room_id, aid, event_map, state_res_store)
-        if (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
+        aev = yield _get_event(room_id, aid, event_map, state_res_store, allow_none=True)
+        if aev and (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
             pl = aev
             break
 
     if pl is None:
         # Couldn't find power level. Check if they're the creator of the room
         for aid in event.auth_event_ids():
-            aev = yield _get_event(room_id, aid, event_map, state_res_store)
-            if (aev.type, aev.state_key) == (EventTypes.Create, ""):
+            aev = yield _get_event(room_id, aid, event_map, state_res_store, allow_none=True)
+            if aev and (aev.type, aev.state_key) == (EventTypes.Create, ""):
                 if aev.content.get("creator") == event.sender:
                     return 100
                 break
@@ -403,9 +403,9 @@ def _iterative_auth_checks(
 
         auth_events = {}
         for aid in event.auth_event_ids():
-            ev = yield _get_event(room_id, aid, event_map, state_res_store)
+            ev = yield _get_event(room_id, aid, event_map, state_res_store, allow_none=True)
 
-            if ev.rejected_reason is None:
+            if ev and ev.rejected_reason is None:
                 auth_events[(ev.type, ev.state_key)] = ev
 
         for key in event_auth.auth_types_for_event(event):
@@ -516,7 +516,7 @@ def _get_mainline_depth_for_event(event, mainline_map, event_map, state_res_stor
 
 
 @defer.inlineCallbacks
-def _get_event(room_id, event_id, event_map, state_res_store):
+def _get_event(room_id, event_id, event_map, state_res_store, allow_none=False):
     """Helper function to look up event in event_map, falling back to looking
     it up in the store
 
@@ -532,7 +532,9 @@ def _get_event(room_id, event_id, event_map, state_res_store):
     if event_id not in event_map:
         events = yield state_res_store.get_events([event_id], allow_rejected=True)
         event_map.update(events)
-    event = event_map[event_id]
+    event = event_map.get(event_id)
+    if allow_none and event is None:
+        return None
     assert event is not None
     if event.room_id != room_id:
         raise Exception(