Restconf returns error when RPC generates "ok" reply

[mgsmith1000]

I have an RPC defined in my data model:

rpc dataplane-control {
    input {
        leaf operation {
            mandatory true;
            type ngcom:service-operation;
            description
                "The operation to perform";
        }
        leaf option {
            type string;
            description
                "Option on operation";
        }
    }
    output {
        leaf stdout {
            type string;
        }
    }
}

When I invoke this RPC via restconf, the reply that is generated by the backend callback that is registered for this RPC only contains <ok/>. Restconf interprets this as an invalid reply:

  {
    "ietf-restconf:errors" : {
    "error": {
      "error-type": "application",
      "error-tag": "unknown-element",
      "error-info": {
        "bad-element": "ok"
      },
      "error-severity": "error"
      }
    }
  }

RFC 7950 section 7.14.4 says:

    If the RPC operation invocation succeeded and no output parameters
    are returned, the <rpc-reply> contains a single <ok/> element

The output parameter for the RPC is not mandatory, so a reply of <ok/> seems RFC-compliant.

[olofhagsand]

Agree. The behaviour is wrong.

[olofhagsand]

Sanity check removed for replies due to (1) wrong handling of (2) uncertain of handling of outgoing validation errors.