bug#60566: [PATCH] environment: Fix '--emulate-fhs' option overriding $PATH.

[Ludovic Courtès]

Hi,

John Kehayias <john.kehayias@protonmail.com> skribis:

> From 57cdc3a8f9c6451aaf17f1fafae0bcf29faeea03 Mon Sep 17 00:00:00 2001
> From: John Kehayias <john.kehayias@protonmail.com>
> Date: Thu, 5 Jan 2023 16:06:19 -0500
> Subject: [PATCH] * environment: Fix '--emulate-fhs' option overriding $PATH.
>
> Fixes <https://issues.guix.gnu.org/60566> where even if "--preserve='^PATH$'"
> was passed to 'guix shell' it would be replaced by just the FHS directories
> when '--emulate-fhs' was also set.
>
> * gnu/scripts/environment.scm (launch-environment): Add the FHS directories to
> $PATH rather than overriding $PATH completely.
> ---
>  guix/scripts/environment.scm | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
> index c7fd8fd340..20fa5850c4 100644
> --- a/guix/scripts/environment.scm
> +++ b/guix/scripts/environment.scm
> @@ -475,10 +475,11 @@ (define* (launch-environment command profile manifest
>       (catch 'system-error
>         (lambda ()
>           (when emulate-fhs?
> -           ;; When running in a container with EMULATE-FHS?, override $PATH
> +           ;; When running in a container with EMULATE-FHS?, augment $PATH
>             ;; (optional, but to better match FHS expectations), and generate
>             ;; /etc/ld.so.cache.
> -           (setenv "PATH" "/bin:/usr/bin:/sbin:/usr/sbin")
> +           (setenv "PATH" (string-append "/bin:/usr/bin:/sbin:/usr/sbin:"
> +                                         (getenv "PATH")))

To be safe, you need to account for (getenv "PATH") returning #f, and
not add a trailing colon in that case.

Other than that, I agree this is a valid change because that would be
consistent with:

--8<---------------cut here---------------start------------->8---
$ PATH=/foo $(type -P guix) shell -E ^PATH$ -C coreutils -- env |grep ^PATH
PATH=/gnu/store/pfl0lyqbs557khv7rw90bzp24qp2lqsn-profile/bin:/foo
--8<---------------cut here---------------end--------------->8---

Perhaps you can add a line to test it in
‘tests/guix-environment-container.sh’?

Thanks,
Ludo’.