bug#38243: Zsh does not load /etc/profile values by default

[Leo Prikler <leo.prikler@student.tugraz.at>]

Am Samstag, den 07.12.2019, 22:15 -0800 schrieb Danny O'Brien:
> I took a closer look at this, and currently Zsh users have
> /etc/profile included in their environment by virtue of a default
> $HOME/.zprofile, which is created in their home directory when they
> are created (via `useradd` and /etc/skel ).
It appears, though, that some Guix users lack this skeleton, perhaps
those who used it before the change.

> I'm a little stuck to know what to do here -- if we source
> /etc/profile in /etc/zprofile, then we risk sourcing it twice for
> users who have the current default ~/.zprofile already in their home
> directories`. OTOH, if users come to Guix System with their own pre-
> existing home directory, then they may well struggle --- as I did --
> because important environment variables aren't set by their
> established ~/.zshrc, ~/.zprofile or ~/.zlogin setups.
I don't think the problem is as bad as you make it out to be.  If we
write channel news describing the move of .zprofile to /etc/zprofile,
people ought to see it and be able to prevent the double-sourcing.


> I *think* the right thing to do is to drop the current
> /etc/skel/.zprofile and establish that /etc/zprofile (and other
> shells) should source /etc/profile . Guix System does a lot of setup
> in /etc/profile including including $GUIX_PROFILE/etc/profile.  It
> would be best if this automatically happened, whatever is going on in
> individual home directories. I'm a Guix newbie though, so I'm happy
> to take advice!  Archlinux has a one-line /etc/zprofile which sources
> /etc/profile ; Debian does not; I have not checked other
> distributions, but I could.
The real problem with $GUIX_PROFILE/etc/profile is its shell-specific
behaviour.  The weird syntax used there *happens* to be supported by
zsh, but other shells (most notably fish, but e.g. also Eshell[1]) do
not like it.
To solve this problem not just for one shell, but for all of them, we
should write a portable $GUIX_PROFILE/etc/profile.  Same for
/etc/profile.  Then we can source it from other shells.  Again,
sourcing it from /etc/zprofile is fine even without that change, as zsh
happens to eat this syntax without complaints, but other shells do not
like it.

Regards,
Leo

[1] Eshell is a weird one.  Sourceing the file directly appears to
work, but does nothing.  Setting $GUIX_PROFILE instead causes the user
to be prompted for an alias.