"ModuleNotFoundError: No module named 'pyexpat'" when run pip install on embedded Python

Bug report

ModuleNotFoundError: No module named 'pyexpat' is raised when use pip install on embedded Python.

But .\python.exe -c 'import xml.parsers.expat' works fine.

Steps to reproduce:

1. Download https://www.python.org/ftp/python/3.10.9/python-3.10.9-embed-win32.zip and extract it, delete python310._pth
2. curl -sSL https://bootstrap.pypa.io/get-pip.py -o get-pip.py
3. python get-pip.py
4. .\python.exe -m pip install pwinput
   Output:

Collecting pwinput
  Using cached pwinput-1.0.2.tar.gz (4.5 kB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
ERROR: Exception:
Traceback (most recent call last):
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\cli\base_command.py", line 160, in exc_logging_wrapper
    status = run_func(*args)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\cli\req_command.py", line 247, in wrapper
    return func(self, options, args)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\commands\install.py", line 400, in run
    requirement_set = resolver.resolve(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\resolver.py", line 92, in resolve
    result = self._result = resolver.resolve(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 481, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 348, in resolve
    self._add_to_criteria(self.state.criteria, r, parent=None)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 172, in _add_to_criteria
    if not criterion.candidates:
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\resolvelib\structs.py", line 151, in __bool__
    return bool(self._sequence)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 155, in __bool__
    return any(self)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 143, in <genexpr>
    return (c for c in iterator if id(c) not in self._incompatible_ids)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 47, in _iter_built
    candidate = func()
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\factory.py", line 206, in _make_candidate_from_link
    self._link_candidate_cache[link] = LinkCandidate(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\candidates.py", line 297, in __init__
    super().__init__(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\candidates.py", line 162, in __init__
    self.dist = self._prepare()
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\candidates.py", line 231, in _prepare
    dist = self._prepare_distribution()
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\resolution\resolvelib\candidates.py", line 308, in _prepare_distribution
    return preparer.prepare_linked_requirement(self._ireq, parallel_builds=True)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\operations\prepare.py", line 491, in prepare_linked_requirement
    return self._prepare_linked_requirement(req, parallel_builds)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\operations\prepare.py", line 577, in _prepare_linked_requirement
    dist = _get_prepared_distribution(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\operations\prepare.py", line 69, in _get_prepared_distribution
    abstract_dist.prepare_distribution_metadata(
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\distributions\sdist.py", line 48, in prepare_distribution_metadata
    self._install_build_reqs(finder)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\distributions\sdist.py", line 118, in _install_build_reqs
    build_reqs = self._get_build_requires_wheel()
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\distributions\sdist.py", line 95, in _get_build_requires_wheel
    return backend.get_requires_for_build_wheel()
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_internal\utils\misc.py", line 685, in get_requires_for_build_wheel
    return super().get_requires_for_build_wheel(config_settings=cs)
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\pep517\wrappers.py", line 173, in get_requires_for_build_wheel
    return self._call_hook('get_requires_for_build_wheel', {
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\pep517\wrappers.py", line 319, in _call_hook
    raise BackendUnavailable(data.get('traceback', ''))
pip._vendor.pep517.wrappers.BackendUnavailable: Traceback (most recent call last):
  File "C:\Users\kk\Downloads\python\lib\site-packages\pip\_vendor\pep517\in_process\_in_process.py", line 77, in _build_backend
    obj = import_module(mod_path)
  File "importlib\__init__.py", line 126, in import_module
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 992, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "C:\Users\kk\AppData\Local\Temp\pip-build-env-wz_0zi4g\overlay\Lib\site-packages\setuptools\__init__.py", line 16, in <module>
    import setuptools.version
  File "C:\Users\kk\AppData\Local\Temp\pip-build-env-wz_0zi4g\overlay\Lib\site-packages\setuptools\version.py", line 1, in <module>
    import pkg_resources
  File "C:\Users\kk\AppData\Local\Temp\pip-build-env-wz_0zi4g\overlay\Lib\site-packages\pkg_resources\__init__.py", line 32, in <module>
    import plistlib
  File "plistlib.py", line 61, in <module>
  File "xml\parsers\expat.py", line 4, in <module>
ModuleNotFoundError: No module named 'pyexpat'

Related issue: https://github.com/Azure/azure-cli/issues/24781, https://github.com/pypa/pip/issues/11670

Your environment

• CPython versions tested on:3.10.9 win32 embedded
• Operating system and architecture:Win11 amd64

使用 Python 3.10.9 win32 embedded ZIP、get-pip.py 以及命令 python.exe -m pip install pwinput 重現問題。首先比較成功的 import xml.parsers.expat 檢查與 pip 建置環境的 traceback，特別注意 plistlib.py 和 xml/parsers/expat.py 項目。當 embedded distribution 能夠在不發生所回報的 pyexpat 失敗的情況下完成此次安裝時，即視為完成。