git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
From: Junio C Hamano <gitster@pobox.com>
To: Han-Wen Nienhuys <hanwen@google.com>
Cc: Han-Wen Nienhuys via GitGitGadget <gitgitgadget@gmail.com>,
	git <git@vger.kernel.org>, Han-Wen Nienhuys <hanwenn@gmail.com>
Subject: Re: [PATCH v3 0/3] Remove special casing for PSEUDOREF updates
Date: Tue, 04 Aug 2020 18:45:17 -0700	[thread overview]
Message-ID: <xmqq1rklrhle.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <xmqqh7tjv6hb.fsf@gitster.c.googlers.com> (Junio C. Hamano's message of "Mon, 03 Aug 2020 13:07:12 -0700")

Junio C Hamano <gitster@pobox.com> writes:

>> Which other refs that aren't really refs should also be supported? The
>> JGit source code suggests that MERGE_HEAD should also be special
>> cased?
>
> I'd think all .git/${SOMETHING}_HEAD are of transitory nature that
> can be left as simple on-disk files that are read (and preferrably
> written---except for FETCH_HEAD for obvious reasons) as if they are
> loose refs handled by files backend.

Sorry for flipping and flopping.  The above goes directly against
the spirit of 09743417 (Modify pseudo refs through ref backend
storage, 2020-07-27).  I still think .git/${SOMETHING}_HEAD except
for FETCH_HEAD should be written and read via the ref subsystem, but
I was wrong to say that it should always be done via the files
backend.  There is no reason to insist on the use of files backend
here.

> It probably makes sense not to
> even write reflog entries for them---it is not like the MERGE_HEAD
> I see now in .git/ directory is an updated version of MERGE_HEAD I
> had there yesterday. "git log -g MERGE_HEAD" gives no interesting
> information.

This still is true, but that is pretty much orthogonal to which
backend is used.

> If the octopus merge does not finish correctly (e.g. due to
> conflicts), with "git reset --hard", we can recover to the original
> state and re-attempt the opeation with "git merge FETCH_HEAD".  Such
> a merge using FETCH_HEAD will produce an octopus merge.
>
> Which means that at least "git merge", FETCH_HEAD is not just a
> regular ref where you can ask what object it points at and it gives
> you a single object name back.
>
> But to other commands like "git log master..FETCH_HEAD", it acts as
> if there is only one object recorded.

All of which means FETCH_HEAD is special and we may not want to
burden the special casing of it to newer backends.

  reply	other threads:[~2020-08-05  1:46 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-06 17:29 [PATCH 0/2] " Han-Wen Nienhuys via GitGitGadget
2020-07-06 17:29 ` [PATCH 1/2] Modify pseudo refs through ref backend storage Han-Wen Nienhuys via GitGitGadget
2020-07-06 20:26   ` Junio C Hamano
2020-07-07 13:56     ` Han-Wen Nienhuys
2020-07-07 15:20       ` Junio C Hamano
2020-07-07 17:15         ` Han-Wen Nienhuys
2020-07-07 18:14           ` Junio C Hamano
2020-07-06 17:29 ` [PATCH 2/2] Make HEAD a PSEUDOREF rather than PER_WORKTREE Han-Wen Nienhuys via GitGitGadget
2020-07-06 20:30   ` Junio C Hamano
2020-07-07  9:24     ` Han-Wen Nienhuys
2020-07-09 21:11 ` [PATCH v2 0/3] Remove special casing for PSEUDOREF updates Han-Wen Nienhuys via GitGitGadget
2020-07-09 21:11   ` [PATCH v2 1/3] t1400: use git rev-parse for testing PSEUDOREF existence Han-Wen Nienhuys via GitGitGadget
2020-07-09 21:11   ` [PATCH v2 2/3] Modify pseudo refs through ref backend storage Han-Wen Nienhuys via GitGitGadget
2020-07-09 21:11   ` [PATCH v2 3/3] Make HEAD a PSEUDOREF rather than PER_WORKTREE Han-Wen Nienhuys via GitGitGadget
2020-07-10 19:25   ` [PATCH v2 0/3] Remove special casing for PSEUDOREF updates Junio C Hamano
2020-07-16 18:45   ` [PATCH v3 " Han-Wen Nienhuys via GitGitGadget
2020-07-16 18:45     ` [PATCH v3 1/3] t1400: use git rev-parse for testing PSEUDOREF existence Han-Wen Nienhuys via GitGitGadget
2020-07-16 18:45     ` [PATCH v3 2/3] Modify pseudo refs through ref backend storage Han-Wen Nienhuys via GitGitGadget
2020-07-17  8:52       ` Johannes Schindelin
2020-07-27 15:41         ` Han-Wen Nienhuys
2020-07-16 18:45     ` [PATCH v3 3/3] Make HEAD a PSEUDOREF rather than PER_WORKTREE Han-Wen Nienhuys via GitGitGadget
2020-07-16 22:09     ` [PATCH v3 0/3] Remove special casing for PSEUDOREF updates Junio C Hamano
2020-07-27  8:50       ` Han-Wen Nienhuys
2020-07-27 16:20         ` Junio C Hamano
2020-08-03 19:07           ` Han-Wen Nienhuys
2020-08-03 20:07             ` Junio C Hamano
2020-08-05  1:45               ` Junio C Hamano [this message]
2020-08-05 10:48                 ` Han-Wen Nienhuys
2020-08-05 15:54                   ` Junio C Hamano
2020-08-10 14:27                     ` Han-Wen Nienhuys
2020-08-10 16:04                       ` Junio C Hamano
2020-08-11 10:49                         ` Han-Wen Nienhuys
2020-08-11 18:38                           ` Junio C Hamano
2020-08-19 13:19                     ` Han-Wen Nienhuys
2020-08-19 15:52                       ` Junio C Hamano
2020-07-27 16:25     ` [PATCH v4 " Han-Wen Nienhuys via GitGitGadget
2020-07-27 16:25       ` [PATCH v4 1/3] t1400: use git rev-parse for testing PSEUDOREF existence Han-Wen Nienhuys via GitGitGadget
2020-07-27 16:25       ` [PATCH v4 2/3] Modify pseudo refs through ref backend storage Han-Wen Nienhuys via GitGitGadget
2020-07-27 16:25       ` [PATCH v4 3/3] Make HEAD a PSEUDOREF rather than PER_WORKTREE Han-Wen Nienhuys via GitGitGadget

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=xmqq1rklrhle.fsf@gitster.c.googlers.com \
    --to=gitster@pobox.com \
    --cc=git@vger.kernel.org \
    --cc=gitgitgadget@gmail.com \
    --cc=hanwen@google.com \
    --cc=hanwenn@gmail.com \
    --subject='Re: [PATCH v3 0/3] Remove special casing for PSEUDOREF updates' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Code repositories for project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).