Assertion error from 'pip list' in virtualenv.

Question

Pip list is throwing an Assertion error and I'm not sure how to resolve. This has just happened after building 2 packages (PyUblas-2013.1 and boost_1_54_0) from source. I am using virtualenv.

Error below;

(virtenv)[user@xyz ~]$ pip list
beautifulsoup4 (4.2.1)
biopython (1.61)
distribute (0.6.35)
methylpy (0.1.0)
MySQL-python (1.2.4)
numpy (1.7.1)
pip (1.4)
py (1.4.15)
pytest (2.3.5)
PyUblas (2013.1)
Exception:
Traceback (most recent call last):
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/basecommand.py", line 134, in main
    status = self.run(options, args)
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/commands/list.py", line 80, in run
    self.run_listing(options)
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/commands/list.py", line 127, in run_listing
    self.output_package_listing(installed_packages)
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/commands/list.py", line 136, in output_package_listing
    if dist_is_editable(dist):
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/util.py", line 347, in dist_is_editable
    req = FrozenRequirement.from_dist(dist, [])
  File "/home/user/virtenv/lib/python2.7/site-packages/pip/__init__.py", line 194, in from_dist
    assert len(specs) == 1 and specs[0][0] == '=='
AssertionError

Can anyone help me troubleshoot???

Thanks,

Answer 1

I think it is because the distribute package is out of date. Certainly the following fixed it for me:

pip install --upgrade distribute

Answer 2

Your pip may be outdated. Even in Ubuntu 14.04 LTS, the pip version it installed using apt-get install python-pip was 1.5.4. Try updating pip manually, and possibly the new packages again as well.

pip --version # 1.5.4
curl -O https://bootstrap.pypa.io/get-pip.py
sudo python get-pip.py
pip --version # 6.0.8

https://pip.pypa.io/en/latest/installing.html

Answer 3

I know it's old but since I had the same problem and the fix didn't helped. Guess does not harm adding my solution.

Just updated pip, from inside of my virtualenv.

pip install --upgrade pip