extras_require behaving differently in setuptools 36.2.1, breaking Twisted test

This Twisted test started failing this morning with setuptools 36.2.1:

https://github.com/twisted/twisted/blob/trunk/src/twisted/python/test/test_setup.py#L76

    def test_distributeTakesExtrasRequire(self):
        """
        Setuptools' Distribution object parses and stores its C{extras_require}
        argument as an attribute.
        """
        extras = dict(im_an_extra_dependency="thing")
        attrs = dict(extras_require=extras)
        distribution = Distribution(attrs)
        self.assertEqual(
            extras,
            distribution.extras_require
        )

With this:

===============================================================================
[FAIL]
Traceback (most recent call last):
  File "/Users/crodrigues/twisted1/src/twisted/python/test/test_setup.py", line 86, in test_distributeTakesExtrasRequire
    distribution.extras_require
  File "/Users/crodrigues/twisted1/src/twisted/trial/_synctest.py", line 432, in assertEqual
    super(_Assertions, self).assertEqual(first, second, msg)
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/case.py", line 515, in assertEqual
    assertion_func(first, second, msg=msg)
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/unittest/case.py", line 837, in assertDictEqual
    self.fail(self._formatMessage(msg, standardMsg))
twisted.trial.unittest.FailTest: {'im_an_extra_dependency': 'thing'} != {'im_an_extra_dependency': ['thing']}
- {'im_an_extra_dependency': 'thing'}
+ {'im_an_extra_dependency': ['thing']}
?                            +       +


twisted.python.test.test_setup.OptionalDependenciesTests.test_distributeTakesExtrasRequire
-------------------------------------------------------------------------------

Looks like the value in the dictionary is now being converted to a list, whereas before it was not.

[benoit-pierre]

Yep sorry, I updated my comment above, it’s d.items() in the lambda.

[rodrigc]

I’ll close this for now, because https://github.com/twisted/twisted/pull/847 seems to work. I don’t know if other setuptools users will hit this, but keep an eye out for it.