_NamespacePath object has no attribute sort

• Pip version: 9.0.1
• Python version: 3.6
• Operating System: macOS

It seems that pip by way of vendoring Setuptools is triggering the issue reported in pypa/setuptools#885 (and may likely be implicated in the ongoing reports of users experiencing the issue). Here’s a traceback that occurs when pip freeze is invoked by tox during a test run after completing the develop-inst-no-deps step.

Traceback (most recent call last):
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/bin/pip", line 7, in <module>
    from pip import main
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/__init__.py", line 26, in <module>
    from pip.utils import get_installed_distributions, get_prog
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/utils/__init__.py", line 27, in <module>
    from pip._vendor import pkg_resources
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3018, in <module>
    @_call_aside
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3004, in _call_aside
    f(*args, **kwargs)
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3046, in _initialize_master_working_set
    dist.activate(replace=False)
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2578, in activate
    declare_namespace(pkg)
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2152, in declare_namespace
    _handle_ns(packageName, path_item)
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2092, in _handle_ns
    _rebuild_mod_path(path, packageName, module)
  File "/Users/jaraco/Dropbox/code/yg/support/yg.piistore/.tox/python/lib/python3.6/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2121, in _rebuild_mod_path
    orig_path.sort(key=position_in_sys_path)
AttributeError: '_NamespacePath' object has no attribute 'sort'

I imagine the only fix is to re-vendor setuptools with 31.0.1 or later.

[Naereen]

I tried these tricks, and as far as now nothing worked, so here is my durty-and-useful fix: in /path/to/usr/local/python3.5/dist-packages/, for the file pip/_vendor/pkg_resources/__init__.py, line 2121, change:

orig_path.sort(key=position_in_sys_path)

with

try:
    orig_path.sort(key=position_in_sys_path)
except AttributeError:
    print("BUG: Is it bad if orig_path is not sorted correctly?")

[RomHartmann]

Could not do anything with pip in my virtualenv. Even got the error when just typing pip.

An easy_install pip in my virtualenv has made it workable again, though the error still appeared at the end of an install.