" TypeError: unsupported operand type(s) for -=: 'Retry' and 'int' " during PIP upgrade

Question

I'm using Ubuntu 16.04.2 LTS in an Acer Laptop and I'm trying to update my pip installation (current version: 8.1.1). When I run the command

pip install --upgrade pip

I get the following output:

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'

I have read the messages in the following pages:

• Python PIP Install throws TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'
• https://github.com/pypa/pip/issues/3943
• https://github.com/pypa/pip/issues/4133

I'm not using any proxy or firewall (unless you count my router as both, idk).

Answer 1

This happens to me when I am behind a corporate proxy. To fix that, run with --proxy=urlOfYourProxy.

For example:

pip install --proxy user:password@http://localproxy:8080