2 files changed, 4 insertions, 0 deletions
diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py
index 8bb17b3a05..e33b29a42c 100644
--- a/synapse/federation/sender/__init__.py
+++ b/synapse/federation/sender/__init__.py
@@ -297,6 +297,8 @@ class FederationSender:
         sent_pdus_destination_dist_total.inc(len(destinations))
         sent_pdus_destination_dist_count.inc()
 
+        assert pdu.internal_metadata.stream_ordering
+
         # track the fact that we have a PDU for these destinations,
         # to allow us to perform catch-up later on if the remote is unreachable
         # for a while.
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py
index bc99af3fdd..db8e456fe8 100644
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -158,6 +158,7 @@ class PerDestinationQueue:
             # yet know if we have anything to catch up (None)
             self._pending_pdus.append(pdu)
         else:
+            assert pdu.internal_metadata.stream_ordering
             self._catchup_last_skipped = pdu.internal_metadata.stream_ordering
 
         self.attempt_new_transaction()
@@ -361,6 +362,7 @@ class PerDestinationQueue:
                         last_successful_stream_ordering = (
                             final_pdu.internal_metadata.stream_ordering
                         )
+                        assert last_successful_stream_ordering
                         await self._store.set_destination_last_successful_stream_ordering(
                             self._destination, last_successful_stream_ordering
                         )