Stop sending incorrect knock_state_events. (#16403)

Synapse was incorrectly implemented with a knock_state_events
property on some APIs (instead of knock_room_state). This was
correct in Synapse 1.70.0, but *both* fields were sent to also be
compatible with Synapse versions expecting the wrong field.

Enough time has passed that only the correct field needs to be
included/handled.

1 files changed, 2 insertions, 11 deletions

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

index 29cd45550a..807a0867cc 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -868,19 +868,10 @@ class FederationHandler:
         # This is a bit of a hack and is cribbing off of invites. Basically we
         # store the room state here and retrieve it again when this event appears
         # in the invitee's sync stream. It is stripped out for all other local users.
-        stripped_room_state = (
-            knock_response.get("knock_room_state")
-            # Since v1.37, Synapse incorrectly used "knock_state_events" for this field.
-            # Thus, we also check for a 'knock_state_events' to support old instances.
-            # See https://github.com/matrix-org/synapse/issues/14088.
-            or knock_response.get("knock_state_events")
-        )
+        stripped_room_state = knock_response.get("knock_room_state")
 
         if stripped_room_state is None:
-            raise KeyError(
-                "Missing 'knock_room_state' (or legacy 'knock_state_events') field in "
-                "send_knock response"
-            )
+            raise KeyError("Missing 'knock_room_state' field in send_knock response")
 
         event.unsigned["knock_room_state"] = stripped_room_state