Add helpers for getting prev and auth events (#4139)

* Add helpers for getting prev and auth events

This is in preparation for allowing the event format to change between
room versions.

1 files changed, 1 insertions, 3 deletions

diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py

index 3fdd63be95..099ace28c1 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -183,9 +183,7 @@ class TransactionQueue(object):
                         # banned then it won't receive the event because it won't
                         # be in the room after the ban.
                         destinations = yield self.state.get_current_hosts_in_room(
-                            event.room_id, latest_event_ids=[
-                                prev_id for prev_id, _ in event.prev_events
-                            ],
+                            event.room_id, latest_event_ids=event.prev_event_ids(),
                         )
                     except Exception:
                         logger.exception(