bug#52269: [PATCH] sitecustomize.py: Honor .pth files.

[Lars-Dominik Braun <lars@6xq.net>]

Hi Maxim,

> +if not matching_sites:
> +    exit(0)
are you sure about using `exit()` here? sitecustomize.py is imported
during startup and this would simply quit the Python interpreter if
GUIX_PYTHONPATH is not set, wouldn’t it? (Can’t test the change
unfortunately, because it’s a massive rebuild.)

> +# Move the entries that were appended to sys.path in front of Python's own
> +# site-packages directory.  This enables Guix packages to override Python's
> +# bundled packages, such as 'pip'.
> +python_site_index = sys.path.index(python_site)
> +new_site_start_index = sys.path.index(matching_sites[0])
> +if python_site_index < new_site_start_index:
> +    sys.path = (sys.path[:python_site_index]
> +                + sys.path[new_site_start_index:]
> +                + sys.path[python_site_index:new_site_start_index])
This is unrelated to the pdb issue, right? I see that it’s necessary
right now, but as suggested in #46848 I’d prefer unbundling
setuptools/pip from python. (I’ll send a v3 of the patchset at some
point.)

Cheers,
Lars