Re: Environment variables on GNOME on foreign distro (Debian)

[宋文武]

Jorge <address@hidden> writes:

> Hi.  On a previous thread [1] I asked about best practices for Guix
> environment variables on foreign distro.  My problem was not
> fundamentally solved, and it resurfaced again recently.

Hello, I'd say it's not a solved problem in general.

> In summary:
>
> I use Guix on an updated Debian buster (with 59 packages from
> buster-backports) to get some up-to-date packages atop Debian stable.
> Currently I set Guix environment variables on ~/.profile, but recently I
> started getting error messages from Evince (my Evince is from Debian's
> APT).  In fact, in /var/log/user.log I get:
>
> Feb 23 17:04:19 jorge--inspiron-5570 org.gnome.Evince.desktop[1788]: 
> /home/jorge/.guix-profile/lib/gio/modules/libdconfsettings.so: cannot open 
> shared object file: Permission denied
> Feb 23 17:04:19 jorge--inspiron-5570 org.gnome.Evince.desktop[1788]: Failed 
> to load module: /home/jorge/.guix-profile/lib/gio/modules/libdconfsettings.so
> Feb 23 17:04:19 jorge--inspiron-5570 evince[5252]: Using the 'memory' 
> GSettings backend.  Your settings will not be saved or shared with other 
> applications.
>
> The problem seems to be that Debian's Evince is seeing the
> `GIO_EXTRA_MODULES' environment variable from Guix.  In fact:
>
>     $ sudo tr \0 \n < "/proc/$(pgrep evince)/environ" | grep GIO_EXTRA_MODULES
>     GIO_EXTRA_MODULES=/home/jorge/.guix-profile/lib/gio/modules

Yes, the host evince (and any GNOME apps, in fact) is not compatible
with gio modules from guix, as they may have different glib versions and
ABI.

>
> Side note: `sudo` was unnecessary in that command.
>
> Ludovic Courtès on 12 Mar 2018 had suggested me to to source
>  ~/.guix-profile/etc/profile from ~/.bash_profile (or similar).
> However, that does not work, at least for me.  If I source Guix's
> etc/profile from ~/.bash_profile, the icons of my graphical Guix
> applications fail to appear in my GNOME docker, because XDG_DATA_DIRS
> was not set by Guix.
Well, ~/.profile and ~/.bash_profile should both works for bash, but
your login manager may not source ~/.bash_profile.

> In fact, if I open gnome-terminal and issue
> `env | grep -i guix`, I see no Guix environment variables.  In fact,
> that happens even inside Guix-installed emacs-next.

For ~/.profile (or ~/.bash_profile) to be loaded, gnome-terminal need to
launch a login shell (by default it's not).

>
> So what should I do?

I guess you can:
  figure out what environment variables from guix are needed, what are not.
    (eg: filter out GIO_EXTRA_MOUDLES)
  figure out how the login manager got environment variables, and set them.
    make sure XDG_DATA_DIRS from guix is added here, so that
    applications can be found by the gnome launcher.
    (eg: only from ~/.profile, or other?)
  for guix only environment variables, find a way to launch them.
    (eg: when launch a guix gnome application that requires GIO_EXTRA_MODULES)

Hope it helps!