bug#39281: gdm doesn't start

[Jack Hill]

According to my git bisect, d36fa50fbf8169018193774782fd21f1b13b9c0e [0] 
is the culprit. It makes some sense that the commit is gnome-related, but 
I have no idea why adding more packages to the environment should cause 
gdm to fail to run properly. Therefore, I am inclined to believe that it is 
a weird timing issue as Leo suspects.

[0] 
http://git.savannah.gnu.org/cgit/guix.git/commit/?id=d36fa50fbf8169018193774782fd21f1b13b9c0e

On Sun, 26 Jan 2020, Leo Prikler wrote:

> I saw the same warnings on one of my systems as well, but it boots
> fine.  On another one, the same behaviour occurs, but GDM can be
> started manually by restarting xorg-server from a TTY.  Note, that I
> can not do so from an SSH remote, because SSH fails to start in a
> similar manner.

My system does indeed have a really slow disk, so perhaps this makes the 
problem more likely to happen. Obviously, it would be nice if gdm started 
correctly, but in a bigger picture, it would be nice if shepherd had a 
better way of dealing with misbehaving services. For example, if shepherd 
know how to check the health of a service and restarted it wasn't 
responding correctly.

I don't know where to go from here. Hopefully someone more knowledgeable 
about gnome and gdm can help us out.

Best,
Jack