Fix not sending events over federation when using sharded event persisters (#8536)

* Fix outbound federaion with multiple event persisters.

We incorrectly notified federation senders that the minimum persisted
stream position had advanced when we got an `RDATA` from an event
persister.

Notifying of federation senders already correctly happens in the
notifier, so we just delete the offending line.

* Change some interfaces to use RoomStreamToken.

By enforcing use of `RoomStreamTokens` we make it less likely that
people pass in random ints that they got from somewhere random.

1 files changed, 7 insertions, 1 deletions

diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 26706bf3e1..793d0db2d9 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -23,6 +23,7 @@ from synapse.api.constants import EventTypes
 from synapse.logging import opentracing
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.push import PusherConfigException
+from synapse.types import RoomStreamToken
 
 from . import push_rule_evaluator, push_tools
 
@@ -114,7 +115,12 @@ class HttpPusher:
         if should_check_for_notifs:
             self._start_processing()
 
-    def on_new_notifications(self, max_stream_ordering):
+    def on_new_notifications(self, max_token: RoomStreamToken):
+        # We just use the minimum stream ordering and ignore the vector clock
+        # component. This is safe to do as long as we *always* ignore the vector
+        # clock components.
+        max_stream_ordering = max_token.stream
+
         self.max_stream_ordering = max(
             max_stream_ordering, self.max_stream_ordering or 0
         )