title: Capybara server & browser error with no trace on server
body: <p>For some reason one of my cucumber tests seem to fail both on the poltergeist driver and from the rails server. </p>
  
  <p>I am getting a full trace on the browser crash but almost nothing on the server side.</p>
  
  <p>When I open the Capybara screenshot I just see</p>
  
  <blockquote>
    <p>Internal Server Error
    undefined method <code>name</code> for nil:NilClass</p>
  </blockquote>
  
  <p>When I tail the test.log</p>
  
  <blockquote>
    <p>Completed 500 Internal Server Error in 0ms (Elasticsearch: 0.0ms)</p>
  </blockquote>
  
  <p>(And no trace)</p>
  
  <p>I have tried</p>
  
  <ul>
  <li>to set <code>config.action_dispatch.show_exceptions = true</code></li>
  <li>the <code>b</code> flag (but it's only showing the detailed trace for the Capybara error</li>
  <li>(my config level is set to :debug already in my environment file)</li>
  </ul>
  
  <p>How can I get the full backtrace on the server side ?</p>
  
  <p>EDIT</p>
  
  <ul>
  <li>Capybara 2.13.0</li>
  <li>Rails 5.0.2</li>
  <li>everything commented in backtrace_silencers</li>
  </ul>