title: Suppress "Ambiguous class resolution" warning on composer dump-autoload -o
body: <p>I'm in the follwoing situation:</p>
  
  <p>I want to deploy a php-app via "git push" on openshift. Dependencies are resolved via composer. The composer.lock file (locking the dependencies to the specific wanted version) is part of the repository.</p>
  
  <p>Dependencies are loaded using the <code>deploy</code> hook script using:</p>
  
  <pre><code>${PHP_DIR}/bin/php $OPENSHIFT_DATA_DIR/composer.phar update --prefer-dist --no-dev -n
  ${PHP_DIR}/bin/php $OPENSHIFT_DATA_DIR/composer.phar dump-autoload --optimize -n
  </code></pre>
  
  <p>One of the dependencies (<a href="https://packagist.org/packages/ezyang/htmlpurifier" rel="nofollow">htmlpurifier</a>) is a dependency of a subdependency. During the second command (dump-autoload --optimize) an error complaining about a "Ambiguous class resolution"-warning is written to stderr(I suppose), causing the deploy to fail. Code is tested locally using unit/integration tests and proven to work, even with this erroneous package.</p>
  
  <blockquote>
    <p>remote: Warning: Ambiguous class resolution, "HTML5" was found in both "/var/lib
    /openshift/abc/app-root/runtime/repo/vendor/ezyang/htmlpuri
    fier/maintenance/PH5P.php" and "/var/lib/openshift/abc/app-
    root/runtime/repo/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Lexer/PH5P.php
    ", the first will be used.</p>
  </blockquote>
  
  <p>Is their a way to ignore this <em>specific</em> warning (e.g. an undocumented option), without ignoring all other warnings and/or messages generated by the command? Or is it possible to exclude a specific subdependency from autoload optimization to avoid the warning and let deploy succeed without ignoring all possible errors?</p>