title: Git never (auto) merge composer.json
body: <p>I would like to avoid git auto merging my composer.json. This way I can have a composer.json in develop branch that uses dev-develop packages, while the one in master only uses dev-master packages.</p>
  
  <p>I could use two composer.json files as suggested <a href="https://stackoverflow.com/questions/16329964/composer-and-multiple-branches">here</a>, but I am afraid that I will end up forgetting to add a bundle in my composer.json for master. Especially when automating tasks, this can end up in a disaster.</p>
  
  <p>So actually I would like git to either:</p>
  
  <ul>
  <li>Always conflict when merging composer.json, so I can manually edit it before comitting to the branch.</li>
  <li>Only merge based on the number of lines .. so if a bundle is added / removed, the number of lines changes, then it should merge, conflict, whatever. If the contents of a line change, it may ignore that .. </li>
  </ul>