bug#36376: Application menu of desktop environment not automatically updated

["Ludovic Courtès" <ludo@gnu.org>]

Hi Maxim,

So I went further to test the initial GLib patch I posted in “real
conditions”.

‘guix system vm-image’ takes an awful lot of time for big images; I
patiently waited for completion for an image of ‘desktop.tmpl’, but then
its root file system turned out to be too small for me to run ‘guix
install’.

So instead I tried this:

  1. ‘guix system vm desktop.tmpl’;

  2. ‘guix install inkscape -p /tmp/test’ on my actual machine;

  3. Start the GNOME VM created above;

  4. Inside the VM, search for Inkscape, notice it’s not there;

  5. Inside the VM, have ~/.guix-profile point to the profile created on
     the host above, and notice that Inkscape becomes available.

Video!

  mpv http://web.fdn.fr/~lcourtes/tmp/gnome-desktop-app-detection.webm

So I think we should include this fix in 1.2.  What do people think?

The main downside is extra grafting, which means extra disk and CPU
usage for our users.  However, libx11 (11K dependents) is also grafted,
so it shouldn’t make things worse (GLib has 6K dependents).

Maxim, did you have a variant of the GLib patch that also checks
/run/current-system?

Thanks,
Ludo’.