From: Nikita Karetnikov <nikita@karetnikov.org>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: bug-guix@gnu.org
Subject: Re: Rollback problems
Date: Thu, 24 Jan 2013 21:44:39 -0500 [thread overview]
Message-ID: <87622mhthi.fsf@karetnikov.org> (raw)
In-Reply-To: <87bocel2vo.fsf@gnu.org> ("Ludovic Courtès"'s message of "(unknown date)")
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> 3. More generally, should the history of generations be linear, or
> should it be a DAG like Git commits?
If the latter is the case, then we can probably use a simple tree. Here
is a related link: [1].
> Regarding (3), it seems that a linear history not only simplifies the
> implementation, but also the user interface, while covering most
> practical use cases.
I agree.
> Let me illustrate. Suppose these generations:
> A ------> B ------> C
> When doing a roll-back from C, one should obviously get back at B. At
> that point, C would still be available. Keeping it around means that
> users can easily switch back to C if B turned out to be less appropriate
> (this answers questions (1) and (2)).
> Once at B, installing or removing packages would delete C, thus allowing
> its generation number to be reused, and create a new generation C’ with
> the same generation number as C:
> A ------> B ------> C’
> At this point, switching back to C is no longer possible.
I like the idea.
Nikita
[1] http://learnyouahaskell.com/zippers#a-very-simple-file-system
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next prev parent reply other threads:[~2013-01-25 2:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-23 20:48 Rollback problems Andreas Enge
2013-01-23 22:58 ` Ludovic Courtès
2013-01-23 23:17 ` Andreas Enge
2013-01-24 11:34 ` Ludovic Courtès
2013-01-24 15:33 ` Alex Sassmannshausen
2013-01-24 15:59 ` Ludovic Courtès
2013-01-24 20:52 ` Ludovic Courtès
2013-01-25 2:44 ` Nikita Karetnikov [this message]
2013-01-25 13:54 ` Alex Sassmannshausen
2013-01-25 14:48 ` Andreas Enge
2013-01-25 14:53 ` Ludovic Courtès
2013-01-27 17:05 ` Ludovic Courtès
2013-01-28 22:10 ` Andreas Enge
2013-01-28 22:44 ` Ludovic Courtès
2013-01-25 3:08 ` Nikita Karetnikov
2013-01-27 17:06 ` Ludovic Courtès
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