Fix purge_room admin API (#6711)

changelog.d/6711.bugfix

@@ -0,0 +1 @@
+Fix `purge_room` admin API.

synapse/storage/purge_events.py

@@ -34,7 +34,7 @@ class PurgeEventsStorage(object):
         """
 
         state_groups_to_delete = yield self.stores.main.purge_room(room_id)
-        yield self.stores.main.purge_room_state(room_id, state_groups_to_delete)
+        yield self.stores.state.purge_room_state(room_id, state_groups_to_delete)
 
     @defer.inlineCallbacks
     def purge_history(self, room_id, token, delete_local_events):

tests/rest/admin/test_admin.py

@@ -337,7 +337,7 @@ class PurgeRoomTestCase(unittest.HomeserverTestCase):
             "local_invites",
             "room_account_data",
             "room_tags",
-            "state_groups",
+            # "state_groups",  # Current impl leaves orphaned state groups around.
             "state_groups_state",
         ):
             count = self.get_success(
@@ -351,8 +351,6 @@ class PurgeRoomTestCase(unittest.HomeserverTestCase):
 
             self.assertEqual(count, 0, msg="Rows not purged in {}".format(table))
 
-    test_purge_room.skip = "Disabled because it's currently broken"
-
 
 class QuarantineMediaTestCase(unittest.HomeserverTestCase):
     """Test /quarantine_media admin API.