bug#51466: guix shell --check reports missing PKG_CONFIG_PATH on Debian bookworm

["Ludovic Courtès" <ludo@gnu.org>]

Hi!

Vagrant Cascadian <vagrant@debian.org> skribis:

> Most things seem to work fine, but noticed an oddity with guix shell:
>
> vagrant@vagranttdgxbookworm:~$ guix shell --pure --check --development guix guix git less
>
> guix shell: checking the environment variables visible from shell
> '/bin/bash'...
> guix shell: warning: variable 'PKG_CONFIG_PATH' is missing from shell

[...]

> vagrant@vagranttdgxbookworm:~$ guix shell --pure --development guix guix git less
>
> vagrant@vagranttdgxbookworm:~$ echo $PKG_CONFIG_PATH
> /gnu/store/9vk59alg27y0cp1za91nfdjiy718cn1f-profile/lib/pkgconfig

Notice that it doesn’t complain about any of the other environment
variables (there are 10 of them according to ‘guix shell -D guix
--search-paths|wc -l’).

If you look at ‘child-shell-environment’ in (guix scripts environment),
it runs this in the child shell:

  env || /usr/bin/env || set; echo GUIX-CHECK-DONE; read x; exit

If the shell prints non-newline-terminated stuff before the output of
‘env’, the first line of ‘env’ would be swallowed by the parser below.

Could you run:

  strace -o log -s 500 guix shell --check -D guix

to see exactly what ‘guix shell’ reads?

If there’s nothing obvious, you know the story: we can always add ‘pk’
calls in ‘child-shell-environment’.  :-)

Thanks,
Ludo’.