Re: Can I easily install GNU Emacs 27.1.50 via Guix?

[Carlo Zancanaro <carlo@zancanaro.id.au>]

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Hi Simon,

On Fri, Dec 18 2020, zimoun wrote:
> Maybe I miss something and I have not dove into all the details 
> so I could be totally wrong.  However, from my understanding, A 
> is built against the shared library C1, and B is built against 
> the shared library C2, and nothing says that C1 and C2 are 
> compatible.

This is true if they are in the same address space, but in this 
case evince runs as a separate process. There's no reason it has 
to load the same libraries as emacs, or have the same GTK_PATH 
variable. You should be able to show this by replacing evince with 
a script that unsets GTK_PATH before invoking the system evince. I 
have attached such a wrapper, if you want to add it to your path 
to check on a foreign distribution (it makes the print dialog in 
evince work for me, even when I run evince from within Guix's 
emacs).

One may argue that the system is functioning correctly, and this 
is an unfortunate consequence of the way that Guix works. I would 
still consider the faulty behaviour a bug - even if it is a result 
of intentional decisions made in Guix's design. Running evince 
(i.e. /usr/bin/evince) is failing because of an environment 
variable that Guix's wrapper sets for emacs. That environment 
variable is propagated to child processes (as environment 
variables are), and in this instance that causes the child process 
to misbehave. This is a bug caused by Guix's wrapping of emacs.

>> I run into a similar problem where my window manager 
>> (awesomewm) sets LD_LIBRARY_PATH, which then propagates to 
>> everything I run from my session. It's quite a pain. I thought 
>> there was an open issue for this, but I can't seem to find it 
>> at the moment.
>
> On foreign distro or Guix System?

I am using Guix on a foreign distribution. I imagine a Guix system 
would mask this bug because we wrap lots of programs (using 
wrap-program or similar) so that they explicitly set the 
environment variables they run with, but it may still be possible 
to provoke it Guix built binaries. I haven't tried.

Carlo


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#!/bin/sh

unset GTK_PATH
/usr/bin/evince "$@"