invalid update to service definition does not fail during registration

[fredwangwang]

Nomad version

0.12.5

Operating system and Environment details

linux

Issue

Update to the service stanza with an invalid configuration does not fail during deployment, as it should do normally.
The job file below normally will trigger an error during deployment saying:

unable to get address for service "example-service": invalid port "8080": port label not found

However, the validation failed to detect the wrong check stanza if the job file is deployed first without check, then adding the check in a subsequent deployment.

Reproduction steps

1. remove the check section from the job file below and deploy
2. add the check section back and deploy
3. deploy finishes "successfully" however no check is registered as the check is invalid.

Job file (if appropriate)

Click this to expand

job "example-job" {
  datacenters = ["dc1"]

  group "example-service-api-group" {
    service {
      name = "example-service"
      port = "8080"

      check {
        type     = "http"
        path     = "/"
        interval = "5s"
        timeout  = "1s"
      }
    }

    task "example-fake" {
      driver = "docker"

      config {
        image = "nicholasjackson/fake-service:v0.12.0"
      }

      env {
        LISTEN_ADDR = "0.0.0.0:8080"
      }
    }
  }
}

[tgross]

I tested this out on the Nomad 1.0-rc and I was not able to get the validation error whether I added the check in an update or in the initial registration.