title: What does a "Could not find .egg-info directory in install record" from pip mean?
body: <p>Since updating the the most recent <code>setuptools</code> (6.0.1) I get an warning (yellow)</p>
  
  <pre><code>Could not find .egg-info directory in install record for ...
  </code></pre>
  
  <p>for all the packages I've updated. For example, when updating Twisted I get</p>
  
  <pre><code>Could not find .egg-info directory in install record for Twisted from https://pypi.python.org/packages/source/T/Twisted/Twisted-14.0.2.tar.bz2#md5=.... in /Library/Python/2.7/site-packages
  </code></pre>
  
  <p>The package updates seems to succeed, however.</p>
  
  <p>What does this warning mean? What can I do to respond to it?</p>