title: How to use GitLab CI only:changes with only:refs?
body: <p>My <code>.gitlab-ci.yml</code> configuration has a job like:</p>
  
  <pre><code>Lint dummy:
    stage: prepare
    tags: [my-tag]
    only:
      refs: [merge_requests]
      changes: [Thorfile]
    script: "/bin/true"
  </code></pre>
  
  <p>The only difference from the real job is the <code>tags</code>. Everything else is exactly the same.</p>
  
  <p>Yes, when creating a merge request where <code>Thorfile</code> has <strong>not</strong> been changed, the "Lint dummy" job is still created.</p>
  
  <p>From the documentation as of 2019.03.14 (<a href="https://docs.gitlab.com/ee/ci/yaml/README.html#using-changes-with-merge_requests" rel="nofollow noreferrer">https://docs.gitlab.com/ee/ci/yaml/README.html#using-changes-with-merge_requests</a>)</p>
  
  <blockquote>
    <p>With pipelines for merge requests, make it possible to define if a job should be created base on files modified in a merge request.</p>
    
    <p>For example:</p>
  
  <pre><code>docker build service one:
    script: docker build -t my-service-one-image:$CI_COMMIT_REF_SLUG .
    only:
      refs:
        - merge_requests
      changes:
        - Dockerfile
  </code></pre>
  </blockquote>
  
  <p>I am using GitLab 11.7.5.</p>