SparkRInterpreter always return SUCCESS

{
  "total_statements": 1,
  "statements": [
    {
      "id": 0,
      "state": "available",
      "output": {
        "status": "ok",
        "execution_count": 0,
        "data": {
          "text/plain": "Error in cat(a) : object 'a' not found"
        }
      }
    }
  ]
}