Hi Carlo,

Thank you for your answer, but unfortunately I wasn't yet able to solve the situation with your advice, maybe I'm misinterpreting something.

A small clarification first: the "/etc/profile.d/guix.sh" script  installed by the Guix installation script; what I shared in my previous email is exactly as it was installed, so it wasn't myself who modified guix.sh or created those lines.
With the vanilla "/etc/profile.d/guix.sh" script (the one I shared), and after installing ipython with guix, here is the result of echoing my XDG_DATA_DIRS after a reboot, when I log in through a tty (since Gnome breaks and I can't log in there, as discussed):


Notice that "/home/tomplaa/.guix-profile/share" is repeated, and this is the reason why I previously had written that the last lines in "/etc/profile.d/guix.sh" seemed superfluous to me, because they were appending something that was already there after sourcing the guix profile.

Regarding your suggestion, I tried the following things, all unsuccessful:
  1. modified "/etc/profile.d/guix.sh" with your suggested lines as the beginning of the script;
  2. modified "/etc/profile" with your suggested lines at the beginning of the script;
  3. created a new script "/etc/profile.d/a0.sh" with those lines, so that it would be the first script to be read by the iteration routine called inside "/etc/profile".
Is there anything else I should be trying here?