diff --git a/changelog.d/17301.bugfix b/changelog.d/17301.bugfix
new file mode 100644
index 0000000000..50383cb4a4
--- /dev/null
+++ b/changelog.d/17301.bugfix
@@ -0,0 +1 @@
+Add initial implementation of an experimental [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575) Sliding Sync `/sync` endpoint.
diff --git a/synapse/handlers/sliding_sync.py b/synapse/handlers/sliding_sync.py
index 1c37f83a2b..de4f33abb8 100644
--- a/synapse/handlers/sliding_sync.py
+++ b/synapse/handlers/sliding_sync.py
@@ -275,12 +275,6 @@ class SlidingSyncHandler:
instance_map=immutabledict(instance_to_max_stream_ordering_map),
)
- # If our `to_token` is already the same or ahead of the latest room membership
- # for the user, we can just straight-up return the room list (nothing has
- # changed)
- if membership_snapshot_token.is_before_or_eq(to_token.room_key):
- return sync_room_id_set
-
# Since we fetched the users room list at some point in time after the from/to
# tokens, we need to revert/rewind some membership changes to match the point in
# time of the `to_token`. In particular, we need to make these fixups:
@@ -300,14 +294,20 @@ class SlidingSyncHandler:
# 1) Fetch membership changes that fall in the range from `to_token` up to
# `membership_snapshot_token`
- membership_change_events_after_to_token = (
- await self.store.get_membership_changes_for_user(
- user_id,
- from_key=to_token.room_key,
- to_key=membership_snapshot_token,
- excluded_rooms=self.rooms_to_exclude_globally,
+ #
+ # If our `to_token` is already the same or ahead of the latest room membership
+ # for the user, we don't need to do any "2)" fix-ups and can just straight-up
+ # use the room list from the snapshot as a base (nothing has changed)
+ membership_change_events_after_to_token = []
+ if not membership_snapshot_token.is_before_or_eq(to_token.room_key):
+ membership_change_events_after_to_token = (
+ await self.store.get_membership_changes_for_user(
+ user_id,
+ from_key=to_token.room_key,
+ to_key=membership_snapshot_token,
+ excluded_rooms=self.rooms_to_exclude_globally,
+ )
)
- )
# 1) Assemble a list of the last membership events in some given ranges. Someone
# could have left and joined multiple times during the given range but we only
diff --git a/tests/handlers/test_sliding_sync.py b/tests/handlers/test_sliding_sync.py
index 5c27474b96..41ceb517f0 100644
--- a/tests/handlers/test_sliding_sync.py
+++ b/tests/handlers/test_sliding_sync.py
@@ -326,7 +326,7 @@ class GetSyncRoomIdsForUserTestCase(HomeserverTestCase):
# Leave during the from_token/to_token range (newly_left)
room_id2 = self.helper.create_room_as(user1_id, tok=user1_tok)
- self.helper.leave(room_id1, user1_id, tok=user1_tok)
+ self.helper.leave(room_id2, user1_id, tok=user1_tok)
after_room2_token = self.event_sources.get_current_token()
|
