pip install zc.recipe.egg fails on pip >= 7.x

On Windows, I was using pip 7.0.1 to install some eggs, notably zc.recipe.egg which is part of buildout.

Since I upgraded virtualenv to version 13.1.0, which comes with a local pip wheel and thus installs pip 7.1.0, when I run pip install zc.recipe.egg in my virtual env, I get an error:

D:\Applications\tmp\test2>Scripts\pip.exe install zc.recipe.egg
Collecting zc.recipe.egg
Installing collected packages: zc.recipe.egg
zc.recipe.egg is in an unsupported or invalid wheel

The error message is in an unsupported or invalid wheel is not very explicit and I do not know why pip 7.1.0 (and only this version of pip) is complaining about this egg ?

I only have this problem with this egg…

Does anyone have a clue on what this means, why it appeared when I change my pip version and if there is a way to fix it ?

[mgedmin]

FWIW pip install --no-cache-dir zc.recipe.egg seems to work as a workaround.

[qwcode]

here’s the hidden stack trace for this.
pkg_resources is confused by the “egg” in the name

Exception:                                                                                                                                                                                                                                   
Traceback (most recent call last):                                                                                                                                                                                                           
  File "/home/qwcode/p/pypa/pip/pip/basecommand.py", line 200, in main                                                                                                                                                                       
    status = self.run(options, args)                                                                                                                                                                                                         
  File "/home/qwcode/p/pypa/pip/pip/commands/install.py", line 302, in run                                                                                                                                                                   
    root=options.root_path,                                                                                                                                                                                                                  
  File "/home/qwcode/p/pypa/pip/pip/req/req_set.py", line 657, in install                                                                                                                                                                    
    **kwargs
  File "/home/qwcode/p/pypa/pip/pip/req/req_install.py", line 805, in install
    version = pip.wheel.wheel_version(self.source_dir)
  File "/home/qwcode/p/pypa/pip/pip/wheel.py", line 559, in wheel_version
    wheel_data = dist.get_metadata('WHEEL')
  File "/home/qwcode/p/pypa/pip/pip/_vendor/pkg_resources/__init__.py", line 1611, in get_metadata
    return self._get(self._fn(self.egg_info, name))
  File "/home/qwcode/p/pypa/pip/pip/_vendor/pkg_resources/__init__.py", line 1722, in _get
    with open(path, 'rb') as stream:
IOError: [Errno 2] No such file or directory: '/tmp/pip-build-ucnzjI/zc.recipe.egg/EGG-INFO/WHEEL'