Tweak `GetStateDeltas` behaviour
Improves the control flow of `GetStateDeltas` for clarity and possibly
also fixes a bug where duplicate state delta entries could be inserted
with different memberships instead of being correctly overridden by
`join`.
MODIFY
syncapi/storage/shared/storage_sync.go
syncapi/storage/shared/storage_sync.go
@@ -360,20 +360,36 @@ func (d *DatabaseTransaction) GetStateDeltas(
newlyJoinedRooms := make(map[string]bool, len(state))
for roomID, stateStreamEvents := range state {
for _, ev := range stateStreamEvents {
- if membership, prevMembership := getMembershipFromEvent(ev.Event, userID); membership != "" {
- if membership == gomatrixserverlib.Join && prevMembership != membership {
- // send full room state down instead of a delta
+ // Look for our membership in the state events and skip over any
+ // membership events that are not related to us.
+ membership, prevMembership := getMembershipFromEvent(ev.Event, userID)
+ if membership == "" {
+ continue
+ }
+
+ if membership == gomatrixserverlib.Join {
+ // If our membership is now join but the previous membership wasn't
+ // then this is a "join transition", so we'll insert this room.
+ if prevMembership != membership {
+ // Get the full room state, as we'll send that down for a newly
+ // joined room instead of a delta.
var s []types.StreamEvent
- s, err = d.currentStateStreamEventsForRoom(ctx, roomID, stateFilter)
- if err != nil {
+ if s, err = d.currentStateStreamEventsForRoom(ctx, roomID, stateFilter); err != nil {
if err == sql.ErrNoRows {
continue
}
return nil, nil, err
}
+
+ // Add the information for this room into the state so that
+ // it will get added with all of the rest of the joined rooms.
state[roomID] = s
newlyJoinedRooms[roomID] = true
- continue // we'll add this room in when we do joined rooms
+ }
+
+ // We won't add joined rooms into the delta at this point as they
+ // are added later on.
+ continue
}
deltas = append(deltas, types.StateDelta{
@@ -385,9 +401,9 @@ func (d *DatabaseTransaction) GetStateDeltas(
break
}
}
- }
- // Add in currently joined rooms
+ // Finally, add in currently joined rooms, including those from the
+ // join transitions above.
for _, joinedRoomID := range joinedRoomIDs {
deltas = append(deltas, types.StateDelta{
Membership: gomatrixserverlib.Join,

Tweak `GetStateDeltas` behaviour (#2788)

Improves the control flow of `GetStateDeltas` for clarity and possibly
also fixes a bug where duplicate state delta entries could be inserted
with different memberships instead of being correctly overridden by
`join`.