[bug#56050] [PATCH v2 1/2] etc/guix-install.sh: Initialize XDG base directories.

[Philip McGrath <philip@philipmcgrath.com>]

The default values from the XDG base directory specification make little
sense for Guix System, and some scripts in Guix assume that they are not
"empty or unset": for example, see <https://issues.guix.gnu.org/56050>.
On foreign distros, however, omitting the default values is likely to
break software from the distro, perhaps even preventing the desktop
environment from starting. To smooth over the difference, use the
system-wide configuration to ensure the environment variables are always
explicitly set on foreign distros.

* etc/guix-install.sh (sys_create_init_profile): Explicitly initialize
XDG base directory variables.
---
 etc/guix-install.sh | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/etc/guix-install.sh b/etc/guix-install.sh
index cd1a1c34c1..62a33a55c4 100755
--- a/etc/guix-install.sh
+++ b/etc/guix-install.sh
@@ -504,6 +504,16 @@ sys_create_init_profile()
   # This will not take effect until the next shell or desktop session!
     [ -d "/etc/profile.d" ] || mkdir /etc/profile.d # Just in case
     cat <<"EOF" > /etc/profile.d/guix.sh
+# Explicitly initialize XDG base directory variables to ease compatibility
+# with Guix System: see <https://issues.guix.gnu.org/56050#3>.
+export XDG_DATA_HOME="${XDG_DATA_HOME:-$HOME/.local/share}"
+export XDG_CONFIG_HOME="${XDG_CONFIG_HOME:-$HOME/.config}"
+export XDG_STATE_HOME="${XDG_STATE_HOME:-$HOME/.local/state}"
+export XDG_DATA_DIRS="${XDG_DATA_DIRS:-/usr/local/share/:/usr/share/}"
+export XDG_CONFIG_DIRS="${XDG_CONFIG_DIRS:-/etc/xdg}"
+export XDG_CACHE_HOME="${XDG_CACHE_HOME:-$HOME/.cache}"
+# no default for XDG_RUNTIME_DIR (depends on foreign distro for semantics)
+
 # _GUIX_PROFILE: `guix pull` profile
 _GUIX_PROFILE="$HOME/.config/guix/current"
 export PATH="$_GUIX_PROFILE/bin${PATH:+:}$PATH"
@@ -522,7 +532,7 @@ export GUIX_LOCPATH
 [ -f "$GUIX_PROFILE/etc/profile" ] && . "$GUIX_PROFILE/etc/profile"
 
 # set XDG_DATA_DIRS to include Guix installations
-export XDG_DATA_DIRS="$GUIX_PROFILE/share:${XDG_DATA_DIRS:-/usr/local/share/:/usr/share/}"
+export XDG_DATA_DIRS="$GUIX_PROFILE/share:$XDG_DATA_DIRS"
 EOF
 }
 
-- 
2.32.0