pip install raises ValueError: check_hostname requires server_hostname

[gitsang]

Description

I can't use pip to install anything

Expected behavior

install success

pip version

21.1.1

Python version

python 3.9

OS

Windows10 20H2

How to Reproduce

1. Download python from https://www.python.org/ftp/python/3.9.5/python-3.9.5-amd64.exe
2. Then install it by default
3. Run pip install xxxx
4. Return ValueError: check_hostname requires server_hostname

Output

> pip install pillow

ERROR: Exception:
Traceback (most recent call last):
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\cli\base_command.py", line 180, in _main
    status = self.run(options, args)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\cli\req_command.py", line 204, in wrapper
    return func(self, options, args)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\commands\install.py", line 318, in run
    requirement_set = resolver.resolve(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\resolution\resolvelib\resolver.py", line 127, in resolve
    result = self._result = resolver.resolve(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 473, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 341, in resolve
    name, crit = self._merge_into_criterion(r, parent=None)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 172, in _merge_into_criterion
    if not criterion.candidates:
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\resolvelib\structs.py", line 139, in __bool__
    return bool(self._sequence)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 143, in __bool__
    return any(self)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 129, in <genexpr>
    return (c for c in iterator if id(c) not in self._incompatible_ids)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 30, in _iter_built
    for version, func in infos:
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\resolution\resolvelib\factory.py", line 258, in iter_index_candidate_infos
    result = self._finder.find_best_candidate(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\package_finder.py", line 879, in find_best_candidate
    candidates = self.find_all_candidates(project_name)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\package_finder.py", line 824, in find_all_candidates
    page_candidates = list(page_candidates_it)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\sources.py", line 134, in page_candidates
    yield from self._candidates_from_page(self._link)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\package_finder.py", line 783, in process_project_url
    html_page = self._link_collector.fetch_page(project_url)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\collector.py", line 512, in fetch_page
    return _get_html_page(location, session=self.session)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\collector.py", line 422, in _get_html_page
    resp = _get_html_response(url, session=session)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\index\collector.py", line 120, in _get_html_response
    resp = session.get(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\requests\sessions.py", line 555, in get
    return self.request('GET', url, **kwargs)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_internal\network\session.py", line 449, in request
    return super().request(method, url, *args, **kwargs)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\requests\sessions.py", line 542, in request
    resp = self.send(prep, **send_kwargs)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\requests\sessions.py", line 655, in send
    r = adapter.send(request, **kwargs)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\cachecontrol\adapter.py", line 53, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\requests\adapters.py", line 439, in send
    resp = conn.urlopen(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 696, in urlopen
    self._prepare_proxy(conn)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 964, in _prepare_proxy
    conn.connect()
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\connection.py", line 359, in connect
    conn = self._connect_tls_proxy(hostname, conn)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\connection.py", line 500, in _connect_tls_proxy
    return ssl_wrap_socket(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 432, in ssl_wrap_socket
    ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 474, in _ssl_wrap_socket_impl
    return ssl_context.wrap_socket(sock)
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\ssl.py", line 500, in wrap_socket
    return self.sslsocket_class._create(
  File "c:\users\sangria\appdata\local\programs\python\python39\lib\ssl.py", line 997, in _create
    raise ValueError("check_hostname requires server_hostname")
ValueError: check_hostname requires server_hostname

>pip --version
pip 21.1.1 from c:\users\sangria\appdata\local\programs\python\python39\lib\site-packages\pip (python 3.9)

### Code of Conduct

- [X] I agree to follow the [PSF Code of Conduct](https://www.python.org/psf/conduct/).

[pfmoore]

This looks like a problem with your Python installation. What version of Windows are you using?

[michaldengusiak]

set up separate issue #9975

[pfmoore]

This is a completely different error - your log shows "ValueError: Unable to find resource t32.exe in package pip._vendor.distlib" whereas the OP was getting "ValueError: check_hostname requires server_hostname".

For your problem, one possible thought - is there a file called t32.exe under C:\Users\DengusiakM\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib? If not, could an anti-virus program have "quarantined" that file? If the t32.exe file is missing, then basically your pip installation is corrupted and there's not much we can suggest other than working out what called the corruption and fixing that or reinstalling pip.

Regarding the OP's issue, we still need to know their Windows version to confirm whether it's supported by Python 3.9.

[pfmoore]

You should open that as a separate issue.

[gitsang]

This looks like a problem with your Python installation. What version of Windows are you using?

My windows10 version is 20H2. I have try many times, re-download or reinstall it, but the problem still happend.

[gitsang]

By the way, The python3.9 that install from microsoft store can work.

[Jarmos-san]

Installing Python from the MS Store can get a bit "complicated". There're issues related to it all over the place, here's one I came across a while back - Why I didn't install Python from the Microsoft Store. Even the official docs has a brief section on the topic.

The recommended to get Python is to use the officially provided installer for Windows (it'll even install pip properly!). Further you can refer to the docs to get started with Python on Windows.

[uranusjr]

According to StackOverflow, this is a consequence of urllib3’s proxy syntax change. So the instructions in #9216 (comment) likely would apply.

[uranusjr]

It seems this is a urllib3 bug: urllib3/urllib3#2178. It has been fixed, but we’ll need a urllib3 release. I’ll add this to the 21.2 milestone.

[lati1010]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

[Sexisnull]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

I had the same problem, just close the proxy.

[gitsang]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

I don't think it cased by proxy, I'm very sure my problem appear without proxy.

Anyway, (2021-06-28) I uninstall Python39 from microsoft store, and then reinstall python from https://www.python.org/ftp/python/3.9.5/python-3.9.5-amd64.exe. It can work now.

I don't known what happened. I have do many thing during this time, I'm not sure which operation fix this problem.

Beside, even if I use proxy, I can also use pip install, without problem.

[netherD]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

you fixed my problem

[LiKe241]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

Fixed my problem

[jiyao1998]

Looks like Proxy issue, please try uninstalling any proxy software or remove proxy settings

Yeah, it's so cool! Fixed my problem!