Python setup.py develop fails with: "TypeError: dist must be a Distribution instance"

[Lucas Alvares Gomes]

When running "python setup.py develop" to install Ironic in development mode it fails with:

Installed /opt/stack/ironic
Processing dependencies for ironic==6.2.1.dev485
Searching for futurist!=0.15.0,>=0.11.0
Reading https://pypi.python.org/simple/futurist/
Downloading https://pypi.python.org/packages/55/70/a957c3834a8877cc2fe15f2f042c842825c8dc17ed5b177a0594aff918cf/futurist-0.20.0.tar.gz#md5=6dd31fb46386aa0ace74146133649d58
Best match: futurist 0.20.0
Processing futurist-0.20.0.tar.gz
Writing /tmp/easy_install-EYrvdl/futurist-0.20.0/setup.cfg
Running futurist-0.20.0/setup.py -q bdist_egg --dist-dir /tmp/easy_install-EYrvdl/futurist-0.20.0/egg-dist-tmp-4uP9zD
ERROR:root:Error parsing
Traceback (most recent call last):

...

  File "/usr/lib64/python2.7/distutils/core.py", line 111, in setup
    _setup_distribution = dist = klass(attrs)
  File "/opt/stack/tempest/.tox/py27/lib/python2.7/site-packages/setuptools/dist.py", line 319, in __init__
    _Distribution.__init__(self, attrs)
  File "/usr/lib64/python2.7/distutils/dist.py", line 287, in __init__
    self.finalize_options()
  File "/opt/stack/tempest/.tox/py27/lib/python2.7/site-packages/setuptools/dist.py", line 386, in finalize_options
    ep.load()(self, ep.name, value)
  File "/opt/stack/tempest/.tox/py27/lib/python2.7/site-packages/pbr/core.py", line 119, in pbr
    'Error parsing %s: %s: %s' % (path, e.__class__.__name__, e))
setuptools.sandbox.UnpickleableException: DistutilsSetupError('Error parsing /tmp/easy_install-EYrvdl/futurist-0.20.0/setup.cfg: TypeError: dist must be a Distribution instance',)

[UPDATE]

Installing it with "pip install -e ." works

[Dmitry Tantsur (divius)]

Not sure why it's reported against Ironic, it even fails in Futurist. I'm redirecting it to pbr folks. In the meantime, have you tried upgrading setuptools?

[Doug Hellmann (doug-hellmann)]

The preferred way to install packages is with pip, even in develop mode. Using "pip install -e" is correct.

[Sorin Sbarnea (ssbarnea)]

I encounter this error more and more often, on different packages. Does anyone knows the root cause?