bugfix: ensure unread count updates are immediately passed to clients

Previously they weren't because we didn't have delta logic for them.
This likely broke in the refactor done in
 19f8b4dbf7

sync3/handler/connstate_live.go

@@ -234,6 +234,16 @@ func (s *connStateLive) processLiveUpdate(ctx context.Context, up caches.Update,
 
 			response.Rooms[roomUpdate.RoomID()] = thisRoom
 		}
+		if delta.HighlightCountChanged || delta.NotificationCountChanged {
+			if !exists {
+				// we need to make this room exist. Other deltas are caused by events so the room exists,
+				// but highlight/notif counts are silent
+				thisRoom = sync3.Room{}
+			}
+			thisRoom.NotificationCount = int64(roomUpdate.UserRoomMetadata().NotificationCount)
+			thisRoom.HighlightCount = int64(roomUpdate.UserRoomMetadata().HighlightCount)
+			response.Rooms[roomUpdate.RoomID()] = thisRoom
+		}
 	}
 	return hasUpdates
 }

sync3/lists.go

@@ -31,10 +31,12 @@ type RoomListDelta struct {
 }
 
 type RoomDelta struct {
-	RoomNameChanged    bool
-	JoinCountChanged   bool
-	InviteCountChanged bool
-	Lists              []RoomListDelta
+	RoomNameChanged          bool
+	JoinCountChanged         bool
+	InviteCountChanged       bool
+	NotificationCountChanged bool
+	HighlightCountChanged    bool
+	Lists                    []RoomListDelta
 }
 
 // InternalRequestLists is a list of lists which matches each index position in the request
@@ -54,6 +56,12 @@ func NewInternalRequestLists() *InternalRequestLists {
 func (s *InternalRequestLists) SetRoom(r RoomConnMetadata) (delta RoomDelta) {
 	existing, exists := s.allRooms[r.RoomID]
 	if exists {
+		if existing.NotificationCount != r.NotificationCount {
+			delta.NotificationCountChanged = true
+		}
+		if existing.HighlightCount != r.HighlightCount {
+			delta.HighlightCountChanged = true
+		}
 		delta.InviteCountChanged = !existing.SameInviteCount(&r.RoomMetadata)
 		delta.JoinCountChanged = !existing.SameJoinCount(&r.RoomMetadata)
 		delta.RoomNameChanged = !existing.SameRoomName(&r.RoomMetadata)

tests-e2e/unread_count_test.go

@@ -0,0 +1,58 @@
+package syncv3_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/matrix-org/sliding-sync/sync3"
+	"github.com/matrix-org/sliding-sync/testutils/m"
+)
+
+func TestUnreadCountsUpdate(t *testing.T) {
+	alice := registerNewUser(t)
+	bob := registerNewUser(t)
+	roomID := alice.CreateRoom(t, map[string]interface{}{
+		"preset": "public_chat",
+	})
+	bob.JoinRoom(t, roomID, nil)
+	eventID := bob.SendEventSynced(t, roomID, Event{
+		Type: "m.room.message",
+		Content: map[string]interface{}{
+			"msgtype": "m.text",
+			"body":    "Hello World",
+		},
+	})
+
+	res := alice.SlidingSync(t, sync3.Request{
+		Lists: []sync3.RequestList{
+			{
+				Ranges: sync3.SliceRanges{{0, 20}},
+			},
+		},
+	})
+	m.MatchResponse(t, res, m.MatchRoomSubscriptionsStrict(map[string][]m.RoomMatcher{
+		roomID: {
+			m.MatchRoomNotificationCount(1),
+		},
+	}))
+	alice.MustDoFunc(t, "POST", []string{"_matrix", "client", "v3", "rooms", roomID, "read_markers"}, WithJSONBody(t, map[string]interface{}{
+		"m.fully_read": eventID,
+		"m.read":       eventID,
+	}))
+	alice.SlidingSyncUntil(t, res.Pos, sync3.Request{
+		Lists: []sync3.RequestList{
+			{
+				Ranges: sync3.SliceRanges{{0, 20}},
+			},
+		},
+	}, func(r *sync3.Response) error {
+		room, ok := r.Rooms[roomID]
+		if !ok {
+			return fmt.Errorf("no room %s", roomID)
+		}
+		if room.NotificationCount != 0 {
+			return fmt.Errorf("notif count = %d", room.NotificationCount)
+		}
+		return nil
+	})
+}