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From: David Turner <dturner@twopensource.com>
To: Jeff King <peff@peff.net>, Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, mhagger@alum.mit.edu
Subject: Re: [PATCH v2 00/21] refs backend reroll
Date: Thu, 14 Jan 2016 11:25:52 -0500	[thread overview]
Message-ID: <1452788752.16226.17.camel@twopensource.com> (raw)
In-Reply-To: <20160114092614.GA8533@sigill.intra.peff.net>

On Thu, 2016-01-14 at 04:26 -0500, Jeff King wrote:
> On Tue, Jan 12, 2016 at 04:22:09PM -0800, Junio C Hamano wrote:
> 
> > David Turner <dturner@twopensource.com> writes:
> > 
> > > This version incorporates many changes suggested by Michael
> > > Haggerty,
> > > Junio, Jonathan Nieder, Eric Sunshine, and Jeff King. I think I
> > > have
> > > addressed of the comments that were sent to me.  Those that I
> > > chose
> > > not to incorporate, I responded to on the mailing list.
> > > 
> > > Thanks for all of the feed back so far.
> > 
> > Unfortunately this did not compile for me X-< and with a trivial
> > fix-up, I found that this overlaps with Peff's recent fixes to the
> > locking of symbolic refs.  So for today's integration run, I
> > punted.
> > 
> > I still will push out this topic to the broken-out repository I
> > keep
> > here:
> > 
> >     https://github.com/gitster/git
> > 
> > It's just 'pu' will not have this latest incarnation, but has the
> > older one.
> 
> I took a look at David's changes. The conflicts come from "refs:
> resolve symbolic refs first". I'm not sure I fully understand all
> that
> is going on in that patch, but it looks like after it, we are less
> likely to handle ENOTDIR and d/f conflicts for symrefs, as we skip
> that
> whole code path for REF_ISSYMREF.

We only get into the symref part of that codepath if there's already a
symref present, meaning that d/f conflicts can't happen.

> The rest of the conflicts are related to the fact that all of the
> initial resolution is pulled out of lock_ref_sha1_basic(), and the
> caller is supposed to do it. So I think if create_symref() is going
> to
> call lock_ref_sha1_basic(), as in my series, when combined with
> David's
> it should also be calling dereference_symrefs(). That uses a
> ref_transaction, which we don't have in create_symref() right now,
> but
> it makes sense that we would ultimately want to push symref updates
> through the same transaction/backend system.

I don't think that's quite true.  create_symref *always* creates
symrefs, and never creates underlying refs.  So it calls
lock_ref_sha1_basic(), but since type_p is NULL, it doesn't go into the
resolved-symlinks path; instead, we get into the original codepath.

> So sorry, I don't have a quick resolution to this. I'm hoping David
> can
> make more sense of it than I did.

I was totally convinced that we were doomed, but I think the stupid
resolution basically works, with some minor tweaks.  I'm going to re
-review that patch and resend the series (then go out of town until
Tuesday).

We will need to apply your new d/f conflict check to the LMDB backend's
symref code (presently, it fails your new test), but I'm going to punt
on that for now since d/f conflicts don't cause problems for the LMDB
backend and this is a relatively minor case.  I've added a TODO to the
code.

  reply	other threads:[~2016-01-14 16:26 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-12  1:21 [PATCH v2 00/21] refs backend reroll David Turner
2016-01-12  1:22 ` [PATCH v2 01/21] refs: add a backend method structure with transaction functions David Turner
2016-01-12  1:22 ` [PATCH v2 02/21] refs: add methods for misc ref operations David Turner
2016-01-12  1:22 ` [PATCH v2 03/21] refs: add methods for the ref iterators David Turner
2016-01-12  1:22 ` [PATCH v2 04/21] refs: add do_for_each_per_worktree_ref David Turner
2016-01-12  1:22 ` [PATCH v2 05/21] refs: add methods for reflog David Turner
2016-01-12  1:22 ` [PATCH v2 06/21] refs: add method for initial ref transaction commit David Turner
2016-01-12  1:22 ` [PATCH v2 07/21] refs: add method for delete_refs David Turner
2016-01-12  1:22 ` [PATCH v2 08/21] refs: add methods to init refs db David Turner
2016-01-12  1:22 ` [PATCH v2 09/21] refs: add method to rename refs David Turner
2016-01-12  1:22 ` [PATCH v2 10/21] refs: make lock generic David Turner
2016-01-12  1:22 ` [PATCH v2 11/21] refs: move duplicate check to common code David Turner
2016-01-12  1:22 ` [PATCH v2 12/21] refs: allow log-only updates David Turner
2016-01-12  1:22 ` [PATCH v2 13/21] refs: resolve symbolic refs first David Turner
2016-01-13  0:19   ` Junio C Hamano
2016-01-13 16:33     ` David Turner
2016-01-12  1:22 ` [PATCH v2 14/21] refs: always handle non-normal refs in files backend David Turner
2016-01-13  0:19   ` Junio C Hamano
2016-01-13 16:34     ` David Turner
2016-01-12  1:22 ` [PATCH v2 15/21] init: allow alternate backends to be set for new repos David Turner
2016-01-12  1:22 ` [PATCH v2 16/21] refs: check submodules ref storage config David Turner
2016-01-13  0:19   ` Junio C Hamano
2016-01-13 16:32     ` David Turner
2016-01-13 17:02       ` Junio C Hamano
2016-01-12  1:22 ` [PATCH v2 17/21] clone: use child_process for recursive checkouts David Turner
2016-01-12  1:22 ` [PATCH v2 18/21] refs: allow ref backend to be set for clone David Turner
2016-01-12  1:22 ` [PATCH v2 19/21] svn: learn ref-storage argument David Turner
2016-01-12  1:22 ` [PATCH v2 20/21] refs: add LMDB refs backend David Turner
2016-01-14 20:52   ` Jeff King
2016-01-14 22:30     ` David Turner
2016-01-12  1:22 ` [PATCH v2 21/21] refs: tests for lmdb backend David Turner
2016-01-13  0:22 ` [PATCH v2 00/21] refs backend reroll Junio C Hamano
2016-01-14  9:26   ` Jeff King
2016-01-14 16:25     ` David Turner [this message]
2016-01-14 20:12       ` Jeff King

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