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From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: Josh Triplett <josh@joshtriplett.org>, git@vger.kernel.org
Subject: Re: gc and repack ignore .git/*HEAD when checking reachability
Date: Sat, 9 Jul 2016 09:35:24 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1607090928500.6426@virtualbox> (raw)
In-Reply-To: <xmqqa8hsm4qu.fsf@gitster.mtv.corp.google.com>

Hi Junio,

On Fri, 8 Jul 2016, Junio C Hamano wrote:

> Josh Triplett <josh@joshtriplett.org> writes:
> 
> > That sounds reasonable.  And if they *do* end up taking any time to
> > traverse, it's because they weren't reachable from other anchoring
> > points, so taking the extra time to traverse them seems fine.
> 
> The only thing that is hard is to clearly define _what_ are the new
> anchoring points.
> 
> It cannot be "anything directly under .git that has all-caps name
> that ends with _HEAD".  The ones we write we know are going to be
> removed at some point in time (e.g. "git reset", "git bisect reset",
> "git merge --abort", etc.).  We do not have any control on random
> ones that the users and third-party tools leave behind, holding onto
> irrelevant objects forever.

Please note that bisect already uses the (transient) refs/bisect/
namespace. So I do not think we need to take specific care of the
BISECT_* files.

If we had thought of it back then, we could have used such a transient
namespace also for FETCH_HEAD, CHERRY_PICK_HEAD and also for detached
HEADs (which we should have called "unnamed branches").

Now, how about special-casing *just* these legacy files in gc: HEAD,
FETCH_HEAD, MERGE_HEAD and CHERRY_PICK_HEAD? Any new transient refs should
live in the refs/ namespace, which is already handled.

BTW this issue is getting much more problematic when you have a lot of
worktrees, some of which operate on detached HEADs. Which I do.

Ciao,
Dscho

  parent reply	other threads:[~2016-07-09  7:35 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-08  2:59 gc and repack ignore .git/*HEAD when checking reachability Josh Triplett
2016-07-08  4:34 ` Junio C Hamano
2016-07-08  6:44   ` Josh Triplett
2016-07-08 17:14     ` Junio C Hamano
2016-07-08 19:25       ` Theodore Ts'o
2016-07-08 20:30         ` Junio C Hamano
2016-07-08 23:50           ` Theodore Ts'o
2016-07-09  5:23             ` Josh Triplett
2016-07-08 20:29       ` Josh Triplett
2016-07-09  7:35       ` Johannes Schindelin [this message]
2016-07-09 14:09         ` Josh Triplett
2016-07-09 16:45           ` Duy Nguyen
2016-07-10 10:59             ` Johannes Schindelin
2016-07-10 11:04               ` Duy Nguyen
2016-07-10 14:16                 ` Johannes Schindelin
2016-07-10 15:01                   ` Duy Nguyen
2016-07-11  6:07                     ` Johannes Schindelin
2016-07-11 18:52                   ` Junio C Hamano
2016-07-12 10:47                     ` Johannes Schindelin
2016-07-12 15:26                       ` Jeff King
2016-07-12 15:46                         ` Duy Nguyen
2016-07-12 15:51                           ` Jeff King
2016-07-12 16:13                             ` Duy Nguyen
2016-07-13  8:20                               ` Johannes Schindelin
2016-07-13 14:54                                 ` Duy Nguyen
2016-07-13 18:59                                   ` Johannes Schindelin
2016-07-15 15:46                                     ` Duy Nguyen

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