From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alex Kost <alezost@gmail.com>
Subject: Re: delete profile
Date: Thu, 16 Mar 2017 12:13:48 +0300
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In-Reply-To: <20170314151844.GB15269@mail.thebird.nl> (Pjotr Prins's message
	of "Tue, 14 Mar 2017 15:18:44 +0000")
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To: Pjotr Prins <pjotr.public12@thebird.nl>
Cc: guix-devel@gnu.org

Pjotr Prins (2017-03-14 15:18 +0000) wrote:

> On Tue, Mar 14, 2017 at 05:28:52PM +0300, Alex Kost wrote:
>> No, "$HOME/guix-test-profile" was not a symlink to
>> "/var/guix/profiles/...".  Try this:
>
> Hmmm. You are right. ~/.guix-profile, meanwile, does point inside
> /var/guix.

Yes, "~/.guix-profile" is the only "special" profile that uses this
additional level of symlinking.  Profiles that you create with "guix
package -p ... -i ..." always point directly to store.

> I have wondered before how GC works on profiles not in /var/guix.
>
> Where does it store that state? In the database?

As Ludovic wrote, the links to the created profile generations are put
in "/var/guix/gcroots/auto" and "guix gc" does not clear the store of
these "registered gc roots".

> I mean, if I simply
> remove the symlink
>
>   lrwxrwxrwx  1 wrk   502   51 Feb 19 09:38 guix-build-system-1-link -> /gnu/store/0lyv2p35ziymd6xjrfxy8sp502n2ii5d-profile
>
> how does Guix know it can GC /gnu/store/0lyv2p35ziymd6xjrfxy8sp502n2ii5d-profile?

After you remove "foo-1-link", the according link in
"/var/guix/gcroots/auto" will become dead, so "guix gc" will remove it
and will clear the store of that profile.

-- 
Alex