Avoid resetting state on rejected events

When we get a rejected event, give it the same state_group as its prev_event,
rather than no state_group at all.

This should fix https://github.com/matrix-org/synapse/issues/1935.

1 files changed, 4 insertions, 4 deletions

diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 42e433da85..4d3cfc336f 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -645,6 +645,10 @@ class EventsStore(SQLBaseStore):
             events_and_contexts=events_and_contexts,
         )
 
+        # Insert into the state_groups, state_groups_state, and
+        # event_to_state_groups tables.
+        self._store_mult_state_groups_txn(txn, events_and_contexts)
+
         # _store_rejected_events_txn filters out any events which were
         # rejected, and returns the filtered list.
         events_and_contexts = self._store_rejected_events_txn(
@@ -1075,10 +1079,6 @@ class EventsStore(SQLBaseStore):
             ],
         )
 
-        # Insert into the state_groups, state_groups_state, and
-        # event_to_state_groups tables.
-        self._store_mult_state_groups_txn(txn, events_and_contexts)
-
         # Update the event_forward_extremities, event_backward_extremities and
         # event_edges tables.
         self._handle_mult_prev_events(