pipenv: NameError: name 'WindowsError' is not defined

Same thing on Ubuntu 18.04 with pipenv installed in a venv with:

pip: 18.1 python: 3.6.5 pipenv: 2018.10.13

Found a hacky workaround:

Modify:

…/site-packages/pipenv/vendor/pythonfinder/utils.py

Change the except clause on line 38 to be broader, e.g. except Exception

Still getting this error on 2018.10.13, running MacOS 10.13.6, for some reason. Tried installing both via brew and pip.

$pipenv install

Error %s while executing command %s name 'WindowsError' is not defined /usr/local/bin/pythonz -c import sys; print(sys.version.split()[0])
Traceback (most recent call last):
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/vistir/misc.py", line 103, in _spawn_subprocess
    return subprocess.Popen(cmd, **options)
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 1344, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/bin/pythonz': '/usr/local/bin/pythonz'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "~/Library/Python/3.6/bin/pipenv", line 11, in <module>
    sys.exit(cli())
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/decorators.py", line 64, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/cli/command.py", line 249, in install
    editable_packages=state.installstate.editables,
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/core.py", line 1724, in do_install
    pypi_mirror=pypi_mirror,
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/core.py", line 565, in ensure_project
    pypi_mirror=pypi_mirror,
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/core.py", line 488, in ensure_virtualenv
    python = ensure_python(three=three, python=python)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/core.py", line 401, in ensure_python
    path_to_python = find_a_system_python(python)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/core.py", line 364, in find_a_system_python
    python_entry = finder.find_python_version(line)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/pythonfinder.py", line 91, in find_python_version
    major=major, minor=minor, patch=patch, pre=pre, dev=dev, arch=arch
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/path.py", line 262, in find_python_version
    (c for c in sorted(path_filter, key=version_sort, reverse=True)), None
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/path.py", line 259, in <genexpr>
    path_filter = filter(None, (sub_finder(p) for p in paths if p is not None))
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/mixins.py", line 106, in find_python_version
    py_filter, key=lambda child: child[1].version_sort, reverse=True
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/mixins.py", line 96, in <genexpr>
    if child.as_python
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/cached_property.py", line 35, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/path.py", line 364, in as_python
    self.py_version = PythonVersion.from_path(self.path)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/models/python.py", line 162, in from_path
    py_version = get_python_version(str(path.path))
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/pythonfinder/utils.py", line 37, in get_python_version
    out, _ = vistir.misc.run(version_cmd, block=True, nospin=True)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/vistir/misc.py", line 294, in run
    combine_stderr=combine_stderr
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/vistir/misc.py", line 125, in _create_subprocess
    combine_stderr=combine_stderr)
  File "~/Library/Python/3.6/lib/python/site-packages/pipenv/vendor/vistir/misc.py", line 104, in _spawn_subprocess
    except WindowsError as e:
NameError: name 'WindowsError' is not defined

$pipenv --version
pipenv, version 2018.10.13

The root cause seems to be that when pythonfinder tries to find a Python interpreter for the project, it executes prominent Python executables as it goes. If it hits a file that looks like a Python interpreter, but doesn’t execute properly, the vistir dependency it uses for executing processes raises NameError as it tries to reference WindowsError on a non-Windows environment.

A workaround is to remove such files from your PATH. In my case, I had a leftover pythonz somewhere that tried to use Python 3.6 which I had already removed when upgrading to 3.7.

@techalchemy Do you know of any workarounds until the new version is available?