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

[John Kehayias via Bug reports for GNU Guix <bug-guix@gnu.org>]

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On Wed, Jan 04, 2023 at 11:33 PM, jman wrote:

> Hello,
>
> When emulating a FHS I observe that env vars seems to be not preserved. Example,
> the following command will not preserve $PATH:
>
>     guix shell --container --emulate-fhs --preserve='^PATH$'
>
> When creating a container *without* emulating a FHS, env vars are available,
> example:
>
>     guix shell --container --preserve='^PATH$'
>
> Pastebin log of a sample of this behaviour:
> https://paste.sr.ht/~jman/65e7f96c445504e11f55595b237280e0c1e3ad34
>
> ref: https://lists.gnu.org/archive/html/help-guix/2023-01/msg00002.html
>
> Thanks for an opinion on this

Thanks for reporting, I can confirm this behavior.

Here is a patch for this where the FHS directories are added to the
current value of $PATH. I believe this should in general be fine since
this is the last step before actually calling the command given to 'guix
shell' and thus $PATH has been set or preserved as needed already.

CC'ing Ludo as most familiar with this code. Anything we should be aware
of here? This change to $PATH in the first place wasn't strictly needed
('guix shell' already has the profile bin directory) but I thought made
sense to make it look most like FHS.

Thanks!
John


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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")))
            (invoke "ldconfig" "-X"))
          (apply execlp program program args))
        (lambda _
-- 
2.38.1