title: Jenkinsfile Step Check if Files Changed in Directory?
body: <p>I am out of my league here so forgive me if this is hard to understand. What I am trying to accomplish is to check if any files have changed in a certain directory during a pull request in my Jenkinsfile setup. If there are files that have changed compared to the <code>develop</code> branch, I would like to run the particular stage. This is a declarative pipeline. Let me give you example:</p>
  <pre><code>stage('Publish Common Module') {
    when {
     // can I check if projects/common/ has any files that are different compared to develop?
     // if so, then I want to run the steps in this stage
    }
  }
  </code></pre>
  <p>I am not sure if that gives enough background as to what I am trying to accomplish. The reason for this setup is that there are multiple stages that build a module based on if there are changes in the PR for that module.</p>
  <p>Apologies if this is not enough information to get an accurate answer.</p>