python3: ctypes missing

[lazka]

$ python3 -c "import ctypes"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:/msys64/mingw32/lib/python3.7\ctypes\__init__.py", line 7, in <module>
    from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'

[lazka]

This makes pip fail etc.

[lazka]

Upstream change: python/cpython#9258

[peterbud]

Even with the latest updated python I see pip3 failing in certain cases - is that related or a different problem?

$ pip3 list -o
Exception:
Traceback (most recent call last):
  File "C:/msys64/mingw64/lib/python3.7/site-packages\pip\_internal\basecommand.py", line 141, in main
    status = self.run(options, args)
  File "C:/msys64/mingw64/lib/python3.7/site-packages\pip\_internal\commands\list.py", line 136, in run
    packages = self.get_outdated(packages, options)
  File "C:/msys64/mingw64/lib/python3.7/site-packages\pip\_internal\commands\list.py", line 147, in get_outdated
    dist for dist in self.iter_packages_latest_infos(packages, options)
  File "C:/msys64/mingw64/lib/python3.7/site-packages\pip\_internal\commands\list.py", line 148, in <listcomp>
    if dist.latest_version > dist.parsed_version
TypeError: '>' not supported between instances of 'Version' and 'Version'

$ pacman -Qi mingw-w64-x86_64-python3
Name            : mingw-w64-x86_64-python3
Version         : 3.7.1-2
...
Build Date      : Sun, Oct 21, 2018 9:06:06 PM
Install Date    : Wed, Oct 24, 2018 5:13:35 PM

$ pacman -Qi mingw-w64-x86_64-python3-pip
Name            : mingw-w64-x86_64-python3-pip
Version         : 18.0-2

[lazka]

That's a different issue, looks like something similar to pypa/setuptools#1383

[lazka]

The error for this issue looked like this (in case someone searches for it):

File "D:\msys64\mingw32\bin\pip3-script.py", line 11, in <module>
    load_entry_point('pip==18.0', 'console_scripts', 'pip3')()
File "D:/msys64/mingw32/lib/python3.7/site-packages\pkg_resources\__init__.py", line 484, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
File "D:/msys64/mingw32/lib/python3.7/site-packages\pkg_resources\__init__.py", line 2714, in load_entry_point
    return ep.load()
File "D:/msys64/mingw32/lib/python3.7/site-packages\pkg_resources\__init__.py", line 2332, in load
    return self.resolve()
File "D:/msys64/mingw32/lib/python3.7/site-packages\pkg_resources\__init__.py", line 2338, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\__init__.py", line 42, in <module>
    from pip._internal import cmdoptions
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\cmdoptions.py", line 16, in <module>
    from pip._internal.index import (
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\index.py", line 24, in <module>
    from pip._internal.download import HAS_TLS, is_url, path_to_url, url_to_path
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\download.py", line 34, in <module>
    from pip._internal.locations import write_delete_marker_file
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\locations.py", line 17, in <module>
    USER_CACHE_DIR = appdirs.user_cache_dir("pip")
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\utils\appdirs.py", line 38, in user_cache_dir
    path = os.path.normpath(_get_win_folder("CSIDL_LOCAL_APPDATA"))
File "D:/msys64/mingw32/lib/python3.7/site-packages\pip\_internal\utils\appdirs.py", line 194, in _get_win_folder_from_registry
    import _winreg
ModuleNotFoundError: No module named '_winreg'

It's hitting an older (non-ctypes) fallback code path which was never ported to Python 3.

[peterbud]

@lazka so what would be the solution for pip3?

[lazka]

@peterbud thanks for the reminder, I've opened #4623