From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Creating user profiles
Date: Sun, 13 Jan 2013 23:45:34 +0100
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References: <201301131423.36130.andreas@enge.fr> <87libwrb66.fsf@gnu.org>
	<201301132331.44244.andreas@enge.fr>
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In-Reply-To: <201301132331.44244.andreas@enge.fr> (Andreas Enge's message of
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To: Andreas Enge <andreas@enge.fr>
Cc: bug-guix@gnu.org

Andreas Enge <andreas@enge.fr> skribis:

> I simply applied the patch, and it seems to be part of the solution.
> Upon a first run of "guix-package --list-available", I obtained the error=
=20
> message inviting me to create the directory, which I did. The next call=20
> succeeded. But now $HOME/.guix-profile points to the non-existing=20
> /usr/local/guix-git/var/nix/profiles/per-user/privat/guix-profile, and I=
=20
> get the error:

[...]

>    ?: 0 [symlink "/usr/local/guix-git/var/nix/profiles/per-
> user/privat/guix-profile" ...]
>
> ERROR: In procedure symlink:
> ERROR: In procedure symlink: File exists

Aah, I see.  That=E2=80=99s because it did (file-exists? ".guix-profile"), =
but
this uses stat(2).  So here, because .guix-profile was a dangling
symlink, it returned #f, even though the symlink actually existed.  I
fixed it using =E2=80=98lstat=E2=80=99 instead.

[...]

> I would suggest the following: Before making the $HOME/.guix-profile=20
> symlink, check for the guix-profile symlink in the per-user profile=20
> directory. If it does not exist, create it as a link to the empty user=20
> environment. So there will always be guix-profile-1-link linking to the=20
> empty directory, which might also be useful for roll back (never delete=20
> this first empty environment).

Having this empty user environment on disk should not be needed because
internally, =E2=80=98profile-manifests=E2=80=99 explicitly checks whether t=
he profile
exists, and returns an empty manifest if it doesn=E2=80=99t.

So I=E2=80=99m committing the patch, minus the above bug.

Thanks for the very quick feedback!

Ludo=E2=80=99.