pip3 error - '_NamespacePath' object has no attribute 'sort'

Question

I tried to install a package through pip3, and I got this error. Every pip/pip3 command that I run gives me this error-

alexg@hitbox:~$ pip3 -V
Traceback (most recent call last):
  File "/usr/local/bin/pip3", line 7, in <module>
    from pip import main
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/__init__.py", line 26, in <module>
    from pip.utils import get_installed_distributions, get_prog
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/utils/__init__.py", line 27, in <module>
    from pip._vendor import pkg_resources
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3018, in <module>
    @_call_aside
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3004, in _call_aside
    f(*args, **kwargs)
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 3046, in _initialize_master_working_set
    dist.activate(replace=False)
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2578, in activate
    declare_namespace(pkg)
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2152, in declare_namespace
    _handle_ns(packageName, path_item)
  File "/home/alexg/.local/lib/python3.5/site-packages/pip/_vendor/pkg_resources/__init__.py", line 2092, in _handle_ns
    _rebuild_mod_path(path, packageName, module)
  File "/home/alexg/.local/lib/python3.5/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 have tried running pip3 install --upgrade pip setuptools according to some answers, but every pip command gives me the error. I'm stuck and can't do anything.

What could have caused it, and how can this be fixed?

I'm on Ubuntu 16.04 with Python 3.5.2

Answer 1

I met the same issue with python 3.5.2 and pip3 (9.0.1). And I fixed it by following this workaround: https://github.com/pypa/setuptools/issues/885#issuecomment-307696027

More specifically, I edited line #2121~2122 of this file: "sudo vim /usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py"

#orig_path.sort(key=position_in_sys_path)
#module.__path__[:] = [_normalize_cached(p) for p in orig_path]
orig_path_t = list(orig_path)
orig_path_t.sort(key=position_in_sys_path)
module.__path__[:] = [_normalize_cached(p) for p in orig_path_t]

Answer 2

Upgrading setuptools worked for me:

pip3 install --upgrade setuptools

Answer 3

This may sound weird, because I had this issue and I had tried everything mentioned in SO and GitHub issues. But then I installed pip with easyinstall and pip command is working. Maybe now there are 2 pip packages now. But error is gone.

easy_install pip