title: Jenkins conditional build step ${GitLastCommit}!=${GIT_COMMIT}
body: <p>I've inherited a Jenkins server so I'm trying to determine the purpose of a conditional build step that is failing:</p>
  
  <p><a href="https://i.stack.imgur.com/Wefcv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Wefcv.png" alt="enter image description here"></a></p>
  
  <p>Running the build produces this exception:  </p>
  
  <pre><code>Exception caught evaluating condition: [org.jenkinsci.plugins.tokenmacro.MacroEvaluationException: Unrecognized macro 'GitLastCommit' in '${GitLastCommit}!=e2859cd109f46e889da99391f149ea68c20b1c75'], action = [Don't run]
  </code></pre>
  
  <p>So the value of <code>GIT_COMMIT</code> is being filled but <code>GitLastCommit</code> is not being filled.</p>
  
  <p>Since it doesn't work I'm wondering how to proceed.</p>
  
  <ol>
  <li>What's the purpose of checking for this?</li>
  <li>If I should keep it then how to I ensure that <code>GitLastCommit</code> gets the right value?</li>
  </ol>