code: func (dc *DeploymentController) syncStatusOnly(d *apps.Deployment, rsList []*apps.ReplicaSet) error {
  	newRS, oldRSs, err := dc.getAllReplicaSetsAndSyncRevision(d, rsList, false)
  	if err != nil {
  		return err
  	}
  
  	allRSs := append(oldRSs, newRS)
  	return dc.syncDeploymentStatus(allRSs, newRS, d)
  }
docs: // syncStatusOnly only updates Deployments Status and doesn't take any mutating actions.