Conditional setuptools entry_points
<p>Is it possible to have conditional entry_points defined in setup.py? I noticed that it is possible to <em>tag</em> an entry point using <code>extras</code>, but that entry point will be available even if the package is installed without that extra feature.</p>

<pre><code>setup(name='my.package',
      ...
      extras_require={
          'special': [
              'dependency1',
              'dependency2',
          ],
      },
      ...
      entry_points="""
      [custom_entrypoint]
      handlername = my.package.special:feature [special]
      """,
  )
</code></pre>

<p>It appears as that <code>custom_entrypoint</code> is available even if the package is installed without that <code>special</code> feature (<code>pip install my.package[special]</code>). Is there a simple way of getting something like this working?</p>