bug#46569: python can't find internal pip modules in environment from manifest

[Maxim Cournoyer]

Hello Jelle,

Jelle Licht <jlicht@fsfe.org> writes:

> Python can not load all pip-related python modules when loaded from a
> manifest file, yet seems to work fine when loaded 'directly' as part of
> a `guix environment'-invocation.
>
>
> Provided that we have a file in `hi.py':
>
> import pip
> print("halfwaypoint")
> import pip._internal.index.package_finder
> print("I made it!")

The problem seems to be related to the version of pip used.  The one
bundled with our Python on master is:

$ guix environment --pure --ad-hoc python -- pip3 --version
pip 19.2.3 from
/gnu/store/pw65c67dmzr2m9wbkj5mskhm6ljk6xal-profile/lib/python3.8/site-packages/pip
(python 3.8)

and

$ guix environment --pure --ad-hoc python -- python3 -c 'import 
pip._internal.index.package_finder'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named
'pip._internal.index.package_finder'; 'pip._internal.index' is not a
package

but

$ guix environment --pure --ad-hoc python python-pip -- pip3 --version
pip 20.2.4 from
/gnu/store/d75bwzbla5ybhs0mdw80qy94mawnhhsw-python-pip-20.2.4/lib/python3.8/site-packages/pip
(python 3.8)

and

$ guix environment --pure --ad-hoc python python-pip -- python3 -c 'import 
pip._internal.index.package_finder'
$ echo $?
0

HTH!

Closing.

Maxim