Noop device key changes if they're the same

1 files changed, 5 insertions, 4 deletions

diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py

index a16b9def8d..49b277a1af 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -287,11 +287,12 @@ class E2eKeysHandler(object):
                 device_id, user_id, time_now
             )
             # TODO: Sign the JSON with the server key
-            yield self.store.set_e2e_device_keys(
-                user_id, device_id, time_now,
-                encode_canonical_json(device_keys)
+            changed = yield self.store.set_e2e_device_keys(
+                user_id, device_id, time_now, device_keys,
             )
-            yield self.device_handler.notify_device_update(user_id, [device_id])
+            if changed:
+                # Only notify about device updates *if* the keys actually changed
+                yield self.device_handler.notify_device_update(user_id, [device_id])
 
         one_time_keys = keys.get("one_time_keys", None)
         if one_time_keys: