Python PIP Install throws TypeError: unsupported o

Question

Using pip install for any module apparently on my Ubuntu 16.04 system with python 2.7.11+ throws this error:

TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

What is wrong with pip? How could I reinstall it, if necessary?

Update: Full traceback is below

sunny@sunny:~$ pip install requests
Collecting requests
Exception:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main
    status = self.run(options, args)
  File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 328, in run
    wb.build(autobuilding=True)
  File "/usr/lib/python2.7/dist-packages/pip/wheel.py", line 748, in build
    self.requirement_set.prepare_files(self.finder)
  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 360, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 512, in _prepare_file
    finder, self.upgrade, require_hashes)
  File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 273, in populate_link
    self.link = finder.find_requirement(self, upgrade)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 442, in find_requirement
    all_candidates = self.find_all_candidates(req.name)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 400, in find_all_candidates
    for page in self._get_pages(url_locations, project_name):
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 545, in _get_pages
    page = self._get_page(location)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 648, in _get_page
    return HTMLPage.get_page(link, session=self.session)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 757, in get_page
    "Cache-Control": "max-age=600",
  File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 480, in get
    return self.request('GET', url, **kwargs)
  File "/usr/lib/python2.7/dist-packages/pip/download.py", line 378, in request
    return super(PipSession, self).request(method, url, *args, **kwargs)
  File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 468, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 576, in send
    r = adapter.send(request, **kwargs)
  File "/usr/share/python-wheels/CacheControl-0.11.5-py2.py3-none-any.whl/cachecontrol/adapter.py", line 46, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/adapters.py", line 376, in send
    timeout=timeout
  File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 610, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 228, in increment
    total -= 1
TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

Answer 1

What happens here is that the the vendored versions of request/urllib3 clash when imported in two different places (same code, but different names). If you then have a network error, it doesn't retry to get the wheel, but fails with the above error. See here for a deeper dive into this error.

For the solution with system pip, see above.

If you have this problem in a virtualenv built by python -m venv (which still copies the wheels from /usr/share/python-wheels, even if you have pip installed separately), the easiest way to "fix" it seems to be:

1. create the virtualenv: /usr/bin/python3.6 -m venv ...
2. install requests into the environment (this might raise the above error): <venv>/bin/pip install requests
3. remove the copied versions of requests which would be used by pip: rm <venv>/share/python-wheels/{requests,chardet,urllib3}-*.whl

Now a <venv>/bin/pip uses the installed version of requests which has urllib3 vendored.

Answer 2

This happens to me when I am working behind the proxy. I solve this problem simply by

pip install --proxy http://proxyAddress:Port Package_To_Be_Installed

Answer 3

Ubuntu comes with a version of PIP from precambrian and that's how you have to upgrade it if you do not want to spend hours and hours debugging pip related issues.

apt-get remove python-pip python3-pip
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py
python3 get-pip.py

As you observed I included information for both Python 2.x and 3.x

Answer 4

I was getting this error for any package installation using pip. Later I found that pip requires http_proxy and https_proxy variable to run behind a proxy. After setting these 2 environment variables this issue is fixed.

export http_proxy=http://<username>:<passowrd>@<proxy_ip>:<proxy_port>/
export https_proxy=https://<username>:<passowrd>@<proxy_ip>:<proxy_port>/

Answer 5

Bizarrely if I remove the proxy from the environment and add it to the command line it works for me. For example to upgrade pip itself:

env http_proxy= https_proxy= pip install pip --upgrade --proxy 'http://proxy-url:80'

My issue was having the proxy in the environment. It seems that pip only honors the one in argument.

Answer 6

I got this error when I was trying to create a virtualenv with command virtualenv myVirtualEnv. I just added a sudo before the command; it solved everything.