Add an early return when handling no-op presence updates. (#14855)

This stops us from incrementing the presence stream position for no-op updates.

2 files changed, 6 insertions, 0 deletions

diff --git a/changelog.d/14855.misc b/changelog.d/14855.misc
new file mode 100644

index 0000000000..f0e292f287
--- /dev/null
+++ b/changelog.d/14855.misc
@@ -0,0 +1 @@
+Add an early return when handling no-op presence updates.
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py

index 2af90b25a3..43e4e7b1b4 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -2155,6 +2155,11 @@ class PresenceFederationQueue:
         # This should only be called on a presence writer.
         assert self._presence_writer
 
+        if not states or not destinations:
+            # Ignore calls which either don't have any new states or don't need
+            # to be sent anywhere.
+            return
+
         if self._federation:
             self._federation.send_presence_to_destinations(
                 states=states,