Using a private package index with pip 24.2 results in `ValueError: check_hostname requires server_hostname`

Description

Attempting to install a package from a private package index with pip 24.2 results in a ValueError: check_hostname requires server_hostname error.

I am using the command below:

pip install <package name> --index-url=<private package index>

Expected behavior

Package is downloaded from the index without an error occuring.

pip version

24.2

Python version

3.12

OS

Linux

How to Reproduce

1. Install pip: pip install pip==24.2
2. Try to install a package from the private index. For example with pip install pip==24.1 --index-url=https://163.219.218.169/root/pypi --no-cache-dir
3. The ValueError: check_hostname requires server_hostname exception occurs.

Output

WARNING: There was an error checking the latest version of pip.
ERROR: Exception:
Traceback (most recent call last):
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/cli/base_command.py", line 105, in _run_wrapper
    status = _inner_run()
             ^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/cli/base_command.py", line 96, in _inner_run
    return self.run(options, args)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/cli/req_command.py", line 67, in wrapper
    return func(self, options, args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/commands/install.py", line 379, in run
    requirement_set = resolver.resolve(
                      ^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/resolver.py", line 95, in resolve
    result = self._result = resolver.resolve(
                            ^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers.py", line 546, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers.py", line 397, in resolve
    self._add_to_criteria(self.state.criteria, r, parent=None)
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers.py", line 173, in _add_to_criteria
    if not criterion.candidates:
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/resolvelib/structs.py", line 156, in __bool__
    return bool(self._sequence)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 174, in __bool__
    return any(self)
           ^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 162, in <genexpr>
    return (c for c in iterator if id(c) not in self._incompatible_ids)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 49, in _iter_built
    for version, func in infos:
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 301, in iter_index_candidate_infos
    result = self._finder.find_best_candidate(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/package_finder.py", line 883, in find_best_candidate
    candidates = self.find_all_candidates(project_name)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/package_finder.py", line 824, in find_all_candidates
    page_candidates = list(page_candidates_it)
                      ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/sources.py", line 194, in page_candidates
    yield from self._candidates_from_page(self._link)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/package_finder.py", line 784, in process_project_url
    index_response = self._link_collector.fetch_response(project_url)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/collector.py", line 448, in fetch_response
    return _get_index_content(location, session=self.session)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/collector.py", line 352, in _get_index_content
    resp = _get_simple_response(url, session=session)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/index/collector.py", line 131, in _get_simple_response
    resp = session.get(
           ^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/requests/sessions.py", line 602, in get
    return self.request("GET", url, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_internal/network/session.py", line 522, in request
    return super().request(method, url, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/requests/sessions.py", line 703, in send
    r = adapter.send(request, **kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/requests/adapters.py", line 667, in send
    resp = conn.urlopen(
           ^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/connectionpool.py", line 715, in urlopen
    httplib_response = self._make_request(
                       ^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/connectionpool.py", line 404, in _make_request
    self._validate_conn(conn)
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/connectionpool.py", line 1058, in _validate_conn
    conn.connect()
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/connection.py", line 419, in connect
    self.sock = ssl_wrap_socket(
                ^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/util/ssl_.py", line 453, in ssl_wrap_socket
    ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/urllib3/util/ssl_.py", line 495, in _ssl_wrap_socket_impl
    return ssl_context.wrap_socket(sock)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/work-hitachi/pypi-repository/.venv/lib/python3.12/site-packages/pip/_vendor/truststore/_api.py", line 96, in wrap_socket
    ssl_sock = self._ctx.wrap_socket(
               ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/.pyenv/versions/3.12.3/lib/python3.12/ssl.py", line 455, in wrap_socket
    return self.sslsocket_class._create(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/hoel/.pyenv/versions/3.12.3/lib/python3.12/ssl.py", line 970, in _create
    raise ValueError("check_hostname requires server_hostname")
ValueError: check_hostname requires server_hostname

Other

I am still in the process of setting up the https part of my private package index, and while I was able to use it to some extend with pip==24.1, I had to manually point to the CA certificate. So I cannot exclude the possibility of a wrong setup on my part.

$ pip install pip==24.2 --index-url=https://163.219.218.169/root/pypi --no-cache-dir --use-feature=truststore
Could not Could not fetch URL https://163.219.218.169/root/pypi/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='163.219.218.169', port=443): Max retries exceeded with url: /root/pypi/pip/ (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1000)'))) - skipping

$ pip install pip==24.2 --index-url=https://163.219.218.169/root/pypi --no-cache-dir --cert assets/ca.pem
Successfully installed pip-24.2

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