python ensurepip fails due to being unable to find files

[Brian Inglis]

On 2022-03-19 22:07, The Other wrote:
> Using the most recent version of python3 (3.9.10), I was unable to set up a
> virtual environment with "python -m venv venv". This was due to the
> ensurepip stage failing. As such, I tried running ensurepip directly.
> 
> Output when running "python -m ensurepip":
> 
> Traceback (most recent call last):
>    File "/usr/lib/python3.9/runpy.py", line 188, in _run_module_as_main
>      mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
>    File "/usr/lib/python3.9/runpy.py", line 147, in _get_module_details
>      return _get_module_details(pkg_main_name, error)
>    File "/usr/lib/python3.9/runpy.py", line 111, in _get_module_details
>      __import__(pkg_name)
>    File "/usr/lib/python3.9/ensurepip/__init__.py", line 30, in <module>
>      _SETUPTOOLS_VERSION = _get_most_recent_wheel_version("setuptools")
>    File "/usr/lib/python3.9/ensurepip/__init__.py", line 27, in
> _get_most_recent_wheel_version
>      return str(max(_wheels[pkg], key=distutils.version.LooseVersion))
> ValueError: max() arg is an empty sequence
> 
> Looking at the actual code in __init__.py, the function that is failing
> seems to be constructing a list of .whl files in "_WHEEL_DIR",
> "/usr/share/python-wheels/", and then returning the latest version of the
> desired one (setuptools and pip are requested). However, it can't find any
> .whl files, and so the max() function fails.
> 
> My cygwin installation doesn't even seem to have a python-wheels folder in
> /usr/share, let alone any .whl files in it. I'm not sure if cygwin
> downloads and stores .whl files elsewhere, or if they even get downloaded
> at all.
> 
> The same error occurs for other versions of python3 I have installed,
> including python3.8 and python3.6.
> 
> I have attached my cygcheck.out file as cygcheck.out.txt. My python 3.9
> install is all OK, though some of the older ones are incomplete for pip.

Ensure all Cygwin processes are shut down from cmd or Powershell:

	> tasklist /m cygwin1.dll
	INFO: No tasks are running which match the specified criteria.

or usually:

Image Name                     PID Modules
========================= ======== ===========
bash.exe                      9276 cygwin1.dll
sh.exe                        3844 cygwin1.dll
xinit.exe                    10652 cygwin1.dll
XWin.exe                      3596 cygwin1.dll
dbus-launch.exe               8104 cygwin1.dll
dbus-daemon.exe               1512 cygwin1.dll
gnome-keyring-daemon.exe      6488 cygwin1.dll
fbxkb.exe                     2196 cygwin1.dll
xwin-xdg-menu.exe             3372 cygwin1.dll
gam_server.exe                3580 cygwin1.dll
pcmanfm.exe                   7496 cygwin1.dll
mintty.exe                   18284 cygwin1.dll
bash.exe                      4340 cygwin1.dll
ssh-agent.exe                14608 cygwin1.dll
bash.exe                      8384 cygwin1.dll

but be aware it shows processes, excluding services, using any 
cygwin1.dll if you have multiple environments installed;

or check TaskMgr Details Image path name does not show anything running 
from your Cygwin root bin or related directories.

Download and run latest Cygwin Setup program.

Reinstall incomplete or missing python3{,6,7,8,9}-pip latest versions 
and also install python3{,6,7,8,9}-virtualenv which all preinstall 
dependencies python-{pip,setuptools,wheel}-wheel.

Allow the setup postinstall scripts to complete and check for any issues 
in /var/log/setup.log.full.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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