Proxy error when running "pip install"

We will share the errors and solutions that occurred when upgrading the pip library on the PC (Windows10) at work. It seems to occur when accessing the Internet.

environment

• Windows 10 Pro 1903
• Python 3.8.0
• pip 19.2.3

Background

I tried to upgrade the pip library on my work PC, but I couldn't upgrade with the following error.

$ python -m pip install --upgrade pip
ERROR: Exception:
Traceback (most recent call last):
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\cli\base_command.py", line 188, in main
    status = self.run(options, args)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\commands\install.py", line 345, in run
    resolver.resolve(requirement_set)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\legacy_resolve.py", line 196, in resolve
    self._resolve_one(requirement_set, req)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\legacy_resolve.py", line 359, in _resolve_one
    abstract_dist = self._get_abstract_dist_for(req_to_install)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\legacy_resolve.py", line 297, in _get_abstract_dist_for
    skip_reason = self._check_skip_installed(req)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\legacy_resolve.py", line 267, in _check_skip_installed
    self.finder.find_requirement(req_to_install, upgrade=True)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 1200, in find_requirement
    candidates = self.find_candidates(
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 1183, in find_candidates
    candidates = self.find_all_candidates(project_name)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 1128, in find_all_candidates
    for page in self._get_pages(url_locations, project_name):
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 1282, in _get_pages
    page = _get_html_page(location, session=self.session)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 234, in _get_html_page
    resp = _get_html_response(url, session=session)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\index.py", line 165, in _get_html_response
    resp = session.get(
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 546, in get
    return self.request('GET', url, **kwargs)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_internal\download.py", line 624, in request
    return super(PipSession, self).request(method, url, *args, **kwargs)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 523, in request
    settings = self.merge_environment_settings(
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 700, in merge_environment_settings
    env_proxies = get_environ_proxies(url, no_proxy=no_proxy)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\utils.py", line 761, in get_environ_proxies
    if should_bypass_proxies(url, no_proxy=no_proxy):
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\utils.py", line 745, in should_bypass_proxies
    bypass = proxy_bypass(parsed.hostname)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\utils.py", line 95, in proxy_bypass
    return proxy_bypass_registry(host)
  File "C:\Users\yuya_sato\AppData\Local\Programs\Python\Python38\lib\site-packages\pip\_vendor\requests\utils.py", line 60, in proxy_bypass_registry
    proxyEnable = int(winreg.QueryValueEx(internetSettings,
ValueError: invalid literal for int() with base 10: ''

Solution

Open the Registry Editor and change the type of HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Internet Settings \ ProxyEnable to REG_BINARY.

Finally

I'm not very familiar with this area, so it's still unclear why this solution works. However, since this error occurs frequently, I wrote an article including the meaning of recording to myself.

By the way, it has never occurred on a personal computer (Mac OS).