From: Junio C Hamano <gitster@pobox.com>
To: "Philippe Blain via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Erik Cervin Edin <erik@cervined.in>,
Phillip Wood <phillip.wood@dunelm.org.uk>,
Philippe Blain <levraiphilippeblain@gmail.com>
Subject: Re: [PATCH 5/5] git-rebase.txt: add a note about 'ORIG_HEAD' being overwritten
Date: Sun, 08 Jan 2023 11:16:45 +0900 [thread overview]
Message-ID: <xmqq4jt122k2.fsf@gitster.g> (raw)
In-Reply-To: <9ef427a9a2adfb6a47d13103f00a64df96725560.1673120359.git.gitgitgadget@gmail.com> (Philippe Blain via GitGitGadget's message of "Sat, 07 Jan 2023 19:39:19 +0000")
"Philippe Blain via GitGitGadget" <gitgitgadget@gmail.com> writes:
> From: Philippe Blain <levraiphilippeblain@gmail.com>
>
> 'ORIG_HEAD' is written at the start of the rebase, but is not guaranteed
> to still point to the original branch tip at the end of the rebase.
>
> Indeed, using other commands that write 'ORIG_HEAD' during the rebase,
> like splitting a commit using 'git reset HEAD^', will lead to 'ORIG_HEAD'
> being overwritten.
Is that a news? If a user does "reset", the user is asking that
HEAD is changed and the old state kept in ORIG_HEAD at the same
time, so while it is not wrong per-se to say that user can clobber
ORIG_HEAD after rebase sets it first, it is pretty much expected,
no?
What would be unexpected is if "rebase" overwrote ORIG_HEAD after
user did all these other things while it gave control back and then
it took control back, and it would be worth documenting.
Having said that, I do not mind documenting this. I am not sure "is
not guaranteed" is a good way to phrase what happens, though.
> +[NOTE]
> +`ORIG_HEAD` is not guaranteed to still point to the previous branch tip
> +at the end of the rebase if other commands that write that pseudo-ref
> +(e.g. `git reset`) are used during the rebase. The previous branch tip,
> +however, is accessible using the reflog of the current branch
> +(i.e. `@{1}`, see linkgit:gitrevisions[7]).
`ORIG_HEAD` is set to point at the tip of the previous branch
when `rebase` begins, but the user can run commands (e.g. "git
reset") that overwrites `ORIG_HEAD` while `rebase` gives control
to the user (e.g. while asking to resolve conflict).
It is excellent to mention reflog, which is very much an upward
compatible replacement of ORIG_HEAD.
Thanks.
next prev parent reply other threads:[~2023-01-08 2:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-07 19:39 [PATCH 0/5] Documentation: updates and a correction around 'ORIG_HEAD' Philippe Blain via GitGitGadget
2023-01-07 19:39 ` [PATCH 1/5] git-cherry-pick.txt: do not use 'ORIG_HEAD' in example Philippe Blain via GitGitGadget
2023-01-08 2:05 ` Junio C Hamano
2023-01-09 13:56 ` Philippe Blain
2023-01-07 19:39 ` [PATCH 2/5] git-reset.txt: mention 'ORIG_HEAD' in the Description Philippe Blain via GitGitGadget
2023-01-07 19:39 ` [PATCH 3/5] git-merge.txt: " Philippe Blain via GitGitGadget
2023-01-07 19:39 ` [PATCH 4/5] revisions.txt: be explicit about commands writing 'ORIG_HEAD' Philippe Blain via GitGitGadget
2023-01-08 2:08 ` Junio C Hamano
2023-01-09 14:00 ` Philippe Blain
2023-01-07 19:39 ` [PATCH 5/5] git-rebase.txt: add a note about 'ORIG_HEAD' being overwritten Philippe Blain via GitGitGadget
2023-01-08 2:16 ` Junio C Hamano [this message]
2023-01-09 18:22 ` Philippe Blain
2023-01-10 13:15 ` [PATCH v2 0/5] Documentation: updates and a correction around 'ORIG_HEAD' Philippe Blain via GitGitGadget
2023-01-10 13:15 ` [PATCH v2 1/5] git-cherry-pick.txt: do not use 'ORIG_HEAD' in example Philippe Blain via GitGitGadget
2023-01-10 13:15 ` [PATCH v2 2/5] git-reset.txt: mention 'ORIG_HEAD' in the Description Philippe Blain via GitGitGadget
2023-01-10 13:15 ` [PATCH v2 3/5] git-merge.txt: " Philippe Blain via GitGitGadget
2023-01-10 13:15 ` [PATCH v2 4/5] revisions.txt: be explicit about commands writing 'ORIG_HEAD' Philippe Blain via GitGitGadget
2023-01-10 13:15 ` [PATCH v2 5/5] git-rebase.txt: add a note about 'ORIG_HEAD' being overwritten Philippe Blain via GitGitGadget
2023-01-10 20:06 ` [PATCH v2 0/5] Documentation: updates and a correction around 'ORIG_HEAD' Phillip Wood
2023-01-13 17:56 ` Junio C Hamano
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