Add leave rooms to /sync response

syncapi/routing/filter.go

@@ -21,7 +21,6 @@ import (
 
 	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	"github.com/matrix-org/dendrite/syncapi/storage"
-	"github.com/matrix-org/dendrite/syncapi/sync"
 	"github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
@@ -105,7 +104,7 @@ func PutFilter(
 	limitRes := gjson.GetBytes(body, "room.timeline.limit")
 	if !limitRes.Exists() {
 		util.GetLogger(req.Context()).Infof("missing timeline limit, using default")
-		filter.Room.Timeline.Limit = sync.DefaultTimelineLimit
+		filter.Room.Timeline.Limit = gomatrixserverlib.DefaultRoomEventFilter().Limit
 	}
 
 	// Validate generates a user-friendly error

syncapi/storage/shared/syncserver.go

@@ -698,7 +698,10 @@ func (d *Database) IncrementalSync(
 			To:   toPos.PDUPosition,
 		}
 
-		numRecentEventsPerRoom := filter.Room.Timeline.Limit
+		numRecentEventsPerRoom := gomatrixserverlib.DefaultRoomEventFilter().Limit
+		if filter != nil {
+			numRecentEventsPerRoom = filter.Room.Timeline.Limit
+		}
 
 		joinedRoomIDs, err = d.addPDUDeltaToResponse(
 			ctx, device, r, numRecentEventsPerRoom, wantFullState, res,
@@ -813,11 +816,27 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 			return
 		}
 
-		// TODO: Add "leave" rooms.
-
 		res.Rooms.Join[roomID] = *jr
 	}
 
+	// Extract room state and recent events for all rooms the user has left
+	leaveRoomIDs, err := d.CurrentRoomState.SelectRoomIDsWithMembership(ctx, txn, userID, gomatrixserverlib.Leave)
+	if err != nil {
+		return
+	}
+	// Build up a /sync response. Add leave rooms.
+	for _, roomID := range leaveRoomIDs {
+		var lr *types.LeaveResponse
+		lr, err = d.getLeaveResponseForCompleteSync(
+			ctx, txn, roomID, r, filter, device,
+		)
+		if err != nil {
+			return
+		}
+
+		res.Rooms.Leave[roomID] = *lr
+	}
+
 	// Add peeked rooms.
 	peeks, err := d.Peeks.SelectPeeksInRange(ctx, txn, userID, device.ID, r)
 	if err != nil {
@@ -926,6 +945,33 @@ func (d *Database) getJoinResponseForCompleteSync(
 	return jr, nil
 }
 
+func (d *Database) getLeaveResponseForCompleteSync(
+	ctx context.Context, txn *sql.Tx,
+	roomID string,
+	r types.Range,
+	filter *gomatrixserverlib.Filter,
+	device userapi.Device,
+) (lr *types.LeaveResponse, err error) {
+	jr, err := d.getJoinResponseForCompleteSync(
+		ctx,
+		txn,
+		roomID,
+		r,
+		filter,
+		device,
+	)
+	if err != nil {
+		return
+	}
+
+	lr = types.NewLeaveResponse()
+	lr.Timeline.PrevBatch = jr.Timeline.PrevBatch
+	lr.Timeline.Events = jr.Timeline.Events
+	lr.Timeline.Limited = jr.Timeline.Limited
+	lr.State.Events = jr.State.Events
+	return lr, nil
+}
+
 func (d *Database) CompleteSync(
 	ctx context.Context,
 	res *types.Response,

syncapi/sync/notifier_test.go

@@ -367,7 +367,7 @@ func newTestSyncRequest(userID, deviceID string, since types.StreamingToken) syn
 		timeout:       1 * time.Minute,
 		since:         since,
 		wantFullState: false,
-		limit:         DefaultTimelineLimit,
+		limit:         gomatrixserverlib.DefaultRoomEventFilter().Limit,
 		log:           util.GetLogger(context.TODO()),
 		ctx:           context.TODO(),
 	}

syncapi/sync/request.go

@@ -31,7 +31,6 @@ import (
 
 const defaultSyncTimeout = time.Duration(0)
 const defaultIncludeLeave = false
-const DefaultTimelineLimit = 20
 
 // syncRequest represents a /sync request, with sensible defaults/sanity checks applied.
 type syncRequest struct {