Zacchaeus Scheffer wrote 2 years ago
(address . bug-guix@gnu.org)
871qkfiol2.fsf@gmail.com
Hi all!
$HOME/PROFILE/setup-environment contains the following lines:
case $XDG_CONFIG_DIRS in
*$HOME_ENVIRONMENT/profile/etc/xdg*) ;;
*) export XDG_CONFIG_DIRS=$HOME_ENVIRONMENT/profile/etc/xdg:$XDG_CONFIG_DIRS ;;
esac
There are two bugs in this code. Both bugs revolve around what happens
if XDG_CONFIG_DIRS is unset, as is the case in some foreign distros.
The first problem is if, XDG_CONFIG_DIRS is unset, and
$HOME_ENVIRONMENT/profile/etc/xdg does not exist, then the conditional
resolves to "is the empty string in the empty string", so
XDG_CONFIG_DIRS is prepended with $HOME_ENVIRONMENT/profile/etc/xdg,
despite it not existing. I'm not sure if incuding a nonexistant path in
XDG_CONFIG_DIRS should cause problems, but this scenario is not
mentioned in the XDG specifications[1], so some programs are bound to
crash because of this.
The second problem (more important) relates to how XDG_CONFIG_DIRS is
interpreted if empty vs set to a value. As per the xdg
specifications[1], if XDG_CONFIG_DIRS is unset, then a value of /etc/xdg
should be used. When an empty XDG_CONFIG_DIRS is set by guix home,
programs find a non-empty value and ignore /etc/xdg.
The above problem means that when I do a guix home reconfigure on my
Librem 5 running PureOS, I get a black screen as Phosh fails to start as
it needs files in /etc/xdg. I can fix it by adding:
XDG_CONFIG_DIRS="$XDG_CONFIG_DIRS:/etc/xdg"
to my .zlogin. A similar issue can be seen with the lines regarding
XDG_DATA_DIRS in $HOME/PROFILE/setup-environment. I think a good step
to resovling this issue is to set empty variables to their default value
first. Maybe something like the following in gnu/home/services.scm:267
...
[ -f $PROFILE_FILE ] && . $PROFILE_FILE
[ -z "$XDG_DATA_DIRS"] && XDG_DATA_DIRS=/usr/local/share/:/usr/share/
[ -z "$XDG_CONFIG_DIRS"] && XDG_CONFIG_DIRS=/etc/xdg
case $XDG_DATA_DIRS in
...
This addresses the second problem, but not the first. Someone may find
a more elegant way to deal with both issues.
-Zacchae