title: Why are changes missing without a trace after a merge?
body: <p>while working on our code we encountered a problem inside our <a href="https://i.stack.imgur.com/RGIUz.png" rel="nofollow noreferrer">git repository</a>:<br />
  On august 15th, the method &quot;CheckforLogout&quot; inside the class &quot;UserHelper&quot; was still present (Commit: 08cc360 or green commit in the picture). After the 26th of august, this method was completly gone.</p>
  <p>I checked wether there was a commit where the method was deleted, but there was none.</p>
  <p>After reading a similar <a href="https://stackoverflow.com/questions/60863407/git-changes-are-missing">thread</a> i started bisecting the commits with the result, that the commit 9013cf5 (Yellow commit in the picture) was the &quot;bad one&quot;.</p>
  <p>The probable cause for this behaviour is, that my boss made changes and comitted them to the repository without pulling first. As his respository was rather out of date, a merge was then in order. As a result of this merge, my method was removed.</p>
  <p>Therefore the &quot;bad commit&quot; was out of date and did not have my method.</p>
  <p>The important questions for me:</p>
  <ul>
  <li>Why is there no entry of the method being removed again?</li>
  <li>Can I prevent this behavious from a software side?</li>
  </ul>
  <p>We are currently using GitLab 12.6.4-ee for our git server.</p>
  <p>Thank you for your consideration!</p>