From: Junio C Hamano <gitster@pobox.com>
To: Johan Herland <johan@herland.net>
Cc: Michael Haggerty <mhagger@alum.mit.edu>,
Jeff King <peff@peff.net>,
git@vger.kernel.org
Subject: Re: [PATCH 00/17] Remove assumptions about refname lifetimes
Date: Tue, 21 May 2013 11:39:14 -0700 [thread overview]
Message-ID: <7v7gisnpnx.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <CALKQrgd3=5Rb5wbDGTV7PQfcingimYf08yEHcbfSCkjGDUU_Ng@mail.gmail.com> (Johan Herland's message of "Mon, 20 May 2013 19:03:52 +0200")
Johan Herland <johan@herland.net> writes:
> On Mon, May 20, 2013 at 6:37 PM, Junio C Hamano <gitster@pobox.com> wrote:
> ...
>> That "backing out" can be made more intelligently than just dying
>> with "compare and swap failed--please retry" message, e.g. you at
>> that point notice what you started with, what the other party did
>> while you were working on (i.e. updating refs/tags/), and three-way
>> merge the refs tree, and in cases where "all refs recorded as loose
>> refs" scheme wouldn't have resulted in problematic conflict, such a
>> three-way merge would resolve trivially (you updated refs/heads/ and
>> the update by the other process to refs/tags/ would not conflict
>> with what you did). But the same three-way merge scheme can be
>> employed with the current flat single packed-refs scheme, can't it?
>
> Yes. (albeit without reusing the machinery we already have for doing
> three-way merges)
I do not think that is relevant, as you do *not* want to reuse the
usual three-way xdiff merge machinery that leaves "<=>" markers for
this usage anyway.
But that is not the primary reason why I am beating this dead horse;
it is the following.
Your version of packed-refs file, and his version of packed-refs
file, and the original you started with, are all sorted in a known
order. You just look at lines from all and merge them line by line.
I think that logic should become a new blob-level merge driver that
can be reused for normal in-working-tree objects that are sorted.
For that kind of "sorted wordlist" file, conflicts that may
artificially arise only because two sides updated adjacent lines in
the list and you used the normal xdiff merge machinery is unwanted,
and users would benefit by having such a specialized merge driver
outside the context of merging two proposed list of refs.
prev parent reply other threads:[~2013-05-21 18:39 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-19 20:26 [PATCH 00/17] Remove assumptions about refname lifetimes Michael Haggerty
2013-05-19 20:26 ` [PATCH 01/17] describe: make own copy of refname Michael Haggerty
2013-05-19 20:26 ` [PATCH 02/17] fetch: make own copies of refnames Michael Haggerty
2013-05-19 20:26 ` [PATCH 03/17] add_rev_cmdline(): make a copy of the name argument Michael Haggerty
2013-05-19 20:26 ` [PATCH 04/17] builtin_diff_tree(): make it obvious that function wants two entries Michael Haggerty
2013-05-21 17:27 ` Junio C Hamano
2013-05-23 7:19 ` Michael Haggerty
2013-05-19 20:27 ` [PATCH 05/17] cmd_diff(): use an object_array for holding trees Michael Haggerty
2013-05-21 17:30 ` Junio C Hamano
2013-05-23 7:21 ` Michael Haggerty
2013-05-19 20:27 ` [PATCH 06/17] cmd_diff(): rename local variable "list" -> "entry" Michael Haggerty
2013-05-19 20:27 ` [PATCH 07/17] cmd_diff(): make it obvious which cases are exclusive of each other Michael Haggerty
2013-05-19 20:27 ` [PATCH 08/17] revision: split some overly-long lines Michael Haggerty
2013-05-21 17:34 ` Junio C Hamano
2013-05-23 6:27 ` Michael Haggerty
2013-05-23 17:08 ` Junio C Hamano
2013-05-19 20:27 ` [PATCH 09/17] gc_boundary(): move the check "alloc <= nr" to caller Michael Haggerty
2013-05-21 17:49 ` Junio C Hamano
2013-05-23 7:09 ` Michael Haggerty
2013-05-23 18:02 ` Junio C Hamano
2013-05-19 20:27 ` [PATCH 10/17] get_revision_internal(): make check less mysterious Michael Haggerty
2013-05-21 17:38 ` Junio C Hamano
2013-05-23 6:39 ` Michael Haggerty
2013-05-19 20:27 ` [PATCH 11/17] object_array: add function object_array_filter() Michael Haggerty
2013-05-19 20:27 ` [PATCH 12/17] object_array_remove_duplicates(): rewrite to reduce copying Michael Haggerty
2013-05-19 20:27 ` [PATCH 13/17] fsck: don't put a void*-shaped peg in a char*-shaped hole Michael Haggerty
2013-05-19 20:27 ` [PATCH 14/17] find_first_merges(): initialize merges variable using initializer Michael Haggerty
2013-05-19 20:27 ` [PATCH 15/17] find_first_merges(): remove unnecessary code Michael Haggerty
2013-05-19 20:27 ` [RFC 16/17] object_array_entry: copy name before storing in name field Michael Haggerty
2013-05-20 10:33 ` Johan Herland
2013-05-20 14:42 ` Michael Haggerty
2013-05-20 16:44 ` Jeff King
2013-05-20 21:34 ` Michael Haggerty
2013-05-19 20:27 ` [RFC 17/17] refs: document the lifetime of the refname passed to each_ref_fn Michael Haggerty
2013-05-20 10:28 ` [PATCH 00/17] Remove assumptions about refname lifetimes Johan Herland
2013-05-20 12:15 ` Michael Haggerty
2013-05-20 16:37 ` Junio C Hamano
2013-05-20 16:59 ` Jeff King
2013-05-20 17:08 ` Johan Herland
2013-05-20 18:03 ` Junio C Hamano
2013-05-20 17:03 ` Johan Herland
2013-05-21 18:39 ` Junio C Hamano [this message]
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