fixup! ws commands: add ability to lock backfill for a specific local…

… device ID

Signed-off-by: Sumner Evans <sumner@beeper.com>

matrix.go

@@ -347,35 +347,45 @@ func (mx *WebsocketCommandHandler) HandleSyncProxyError(syncErr *mautrix.RespErr
 	mx.bridge.RequestStartSync()
 }
 
-type LockBackfillForDeviceRequest struct {
+type LockBackfillForDeviceReq struct {
 	DeviceID id.DeviceID `json:"device_id"`
 }
 
+type LockBackfillForDeviceResp struct {
+	Success          bool        `json:"success"`
+	BackfillDeviceID id.DeviceID `json:"backfill_device_id"`
+}
+
 var lockBackfillForDeviceLock sync.Mutex
 
 func (mx *WebsocketCommandHandler) lockBackfillToForDevice(cmd appservice.WebsocketCommand) (bool, any) {
 	lockBackfillForDeviceLock.Lock()
 	defer lockBackfillForDeviceLock.Unlock()
 
-	var req LockBackfillForDeviceRequest
+	var req LockBackfillForDeviceReq
 	if err := json.Unmarshal(cmd.Data, &req); err != nil {
 		return false, fmt.Errorf("failed to parse request: %w", err)
 	}
 
 	deviceID, err := mx.bridge.DB.Backfill.GetLocalBackfillDeviceID(cmd.Ctx, mx.bridge.user.MXID)
 	if err != nil {
-		return false, fmt.Errorf("failed to get local backfill device ID")
+		return false, fmt.Errorf("failed to get local backfill device ID: %w", err)
 	} else if deviceID != "" {
 		if deviceID != req.DeviceID {
-			return false, fmt.Errorf("backfill is already locked to another device")
+			return true, LockBackfillForDeviceResp{
+				Success:          false,
+				BackfillDeviceID: deviceID,
+			}
 		}
-		return true, nil
 	} else {
 		err := mx.bridge.DB.Backfill.SetLocalBackfillDeviceID(cmd.Ctx, mx.bridge.user.MXID, req.DeviceID)
 		if err != nil {
 			return false, fmt.Errorf("failed to set local backfill device ID: %w", err)
 		}
-		return true, nil
+	}
+	return true, LockBackfillForDeviceResp{
+		Success:          true,
+		BackfillDeviceID: req.DeviceID,
 	}
 }