"UndefinedEnvironmentName: 'extra' does not exist in evaluation environment" when defining extra dependencies

[muelli]

• Pip version:
  8.1.2
• Python version:
  2.7
• Operating System:
  Ubuntu 16.04.

$ python -c "import setuptools; print setuptools.__version__"
20.7.0
$ cat requirements.txt 
pytest; extra == "test"
$ pip install --user -r requirements.txt 
Exception:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main
    status = self.run(options, args)
  File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 305, in run
    wheel_cache
  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 291, in populate_requirement_set
    requirement_set.add_requirement(req)
  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 224, in add_requirement
    if not install_req.match_markers():
  File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 823, in match_markers
    return Marker(self.markers).evaluate()
  File "/usr/share/python-wheels/packaging-16.6-py2.py3-none-any.whl/packaging/markers.py", line 278, in evaluate
    return _evaluate_markers(self._markers, current_environment)
  File "/usr/share/python-wheels/packaging-16.6-py2.py3-none-any.whl/packaging/markers.py", line 203, in _evaluate_markers
    lhs_value = _get_env(environment, lhs.value)
  File "/usr/share/python-wheels/packaging-16.6-py2.py3-none-any.whl/packaging/markers.py", line 185, in _get_env
    "{0!r} does not exist in evaluation environment.".format(name)
UndefinedEnvironmentName: 'extra' does not exist in evaluation environment.

but this issue also happens with setuptools 26.1.1.

[ionelmc]

afaik pytest doesn't have a "test" extra. What did you intend to do there?

[dholth]

pytest; extra == "test" is the syntax that would appear in *.dist-info/METADATA if pip install yourpackage[test] should install pytest. It is probably not useful in requirements.txt.

[dstufft]

We do not support extra == "whatever" syntax inside of a requirements.txt file.