From: Siddharth Asthana <siddharthasthana31@gmail•com>
To: phillip.wood@dunelm•org.uk, git@vger•kernel.org
Cc: christian.couder@gmail•com, ps@pks•im, newren@gmail•com,
gitster@pobox•com, karthik.188@gmail•com, code@khaugsbakk•name,
rybak.a.v@gmail•com, jltobler@gmail•com, toon@iotcl•com,
johncai86@gmail•com, johannes.schindelin@gmx•de
Subject: Re: [PATCH 1/1] replay: add --revert option to reverse commit changes
Date: Thu, 27 Nov 2025 01:09:23 +0530 [thread overview]
Message-ID: <38b51e19-7939-4a5e-8ad0-2d8168bc0fac@gmail.com> (raw)
In-Reply-To: <d563b68b-e01d-4b18-bd84-86f36e61a70d@gmail.com>
On 26/11/25 16:40, Phillip Wood wrote:
> Hi Siddharth
>
> On 25/11/2025 17:00, Siddharth Asthana wrote:
>>
>> diff --git a/Documentation/git-replay.adoc
>> b/Documentation/git-replay.adoc
>> index dcb26e8a8e..ad7dc08622 100644
>> --- a/Documentation/git-replay.adoc
>> +++ b/Documentation/git-replay.adoc
>> @@ -54,6 +54,18 @@ which uses the target only as a starting point
>> without updating it.
>> [...]
>> +To revert a range of commits:
>> +
>> +------------
>> +$ git replay --revert --onto main feature~3..feature
>> +------------
>> +
>> +This creates new commits on top of 'main' that reverse the changes
>> introduced
>> +by the last three commits on 'feature'. The 'feature' branch is
>> updated to
>> +point at the last of these revert commits. The 'main' branch is not
>> updated
>> +in this case.
Hi Phillip,
Thanks for the detailed analysis!
>
> I'm struggling to understand when I'd want to do this. Why would I
> want to update 'feature' to point to the reverted version of its last
> tree commits rebased onto 'main'?
You are absolutely right - the `--onto` example I provided doesn't make
practical sense. Elijah's reply clarified the architecture: `--revert`
should be its own mode, not a modifier that combines with `--onto` or
`--advance`.
The realistic use case is reverting commits from a branch where those
commits already exist. For example:
git replay --revert main~3..main
This would revert the last 3 commits on main, creating revert commits on
top of main.
> In order to understand I ran the first tests case which does
>
> git replay --onto topic1 --revert topic1..topic2
>
> after fixing it by adding --ref-action=print the resulting commit log
> looks like
>
> commit d337fab78e90008835f74e890039b464a0308cbe
> Author: author@name <bogus@email@address>
> Date: Thu Apr 7 15:30:13 2005 -0700
>
> Revert "E
> "
>
> This reverts commit bceb3acd81ddd36ba0da391fffa48949a1337276.
>
> commit 47f0cc1c1f1911c0047a4d79d79f7c19c6c7151a
> Author: author@name <bogus@email@address>
> Date: Thu Apr 7 15:30:13 2005 -0700
>
> Revert "D
> "
>
> This reverts commit d953cf2dcc1da8b51934e43fd83dac72d0e267c7.
>
>
> The commits are empty because the original they are reverting each
> create a new file which is then present in the base revision but not
> in either of the merge heads when we revert.
This confirms the tests aren't realistic. In v2, I will create tests
where the commits being reverted are ancestors of the replay target, so
the reverts produce meaningful diffs.
> This suggests to me that it is not a very realistic test and I'm
> still scratching my head to see where "git replay --onto <commit>
> --revert" is useful.
>
> If '--revert' does not make sense with '--onto' then perhaps it should
> be a new mode that takes a ref and acts like '--advance' but reverts
> the commits rather than cherry-picking them. When reverting a range of
> commits it would reduce the likelihood of conflicts to revert then in
> reverse order so we should either recommend passing '--reverse' or
> make that the default when '--revert' is given.
>
> As you can see in the log output above the new function to format the
> revert subject lines is buggy.
Good catch! The bug is in `generate_revert_message()` - I am passing
`orig_message` (which points to the full message including body) to
`sequencer_format_revert_header()`, but that function expects just the
subject line.
Looking at how sequencer.c does it, they use `msg.subject` which is
properly extracted. I need to use `commit_subject_length()` to get just
the subject:
int subject_len = find_commit_subject(message, &orig_message);
char *subject = xmemdupz(orig_message, subject_len);
generate_revert_message(&msg, subject, &based_on->object.oid);
free(subject);
> If you had used test_commit_message() to check the commit message,
> rather than just grepping for ^Revert the tests would have picked that
> up.
You are right. I will use test_commit_message() for proper validation in v2.
Thanks,
Siddharth
>
> Thanks
>
> Phillip
>
next prev parent reply other threads:[~2025-11-26 19:39 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-25 17:00 [PATCH 0/1] replay: add --revert option to reverse commit changes Siddharth Asthana
2025-11-25 17:00 ` [PATCH 1/1] " Siddharth Asthana
2025-11-25 19:22 ` Junio C Hamano
2025-11-25 19:30 ` Junio C Hamano
2025-11-25 19:39 ` Junio C Hamano
2025-11-25 20:06 ` Junio C Hamano
2025-11-26 19:31 ` Siddharth Asthana
2025-11-26 19:28 ` Siddharth Asthana
2025-11-26 19:26 ` Siddharth Asthana
2025-11-26 21:13 ` Junio C Hamano
2025-11-27 19:23 ` Siddharth Asthana
2025-11-26 11:10 ` Phillip Wood
2025-11-26 17:35 ` Elijah Newren
2025-11-26 18:41 ` Junio C Hamano
2025-11-26 21:17 ` Junio C Hamano
2025-11-26 23:06 ` Elijah Newren
2025-11-26 23:14 ` Junio C Hamano
2025-11-26 23:57 ` Elijah Newren
2025-11-26 19:50 ` Siddharth Asthana
2025-11-26 19:39 ` Siddharth Asthana [this message]
2025-11-27 16:21 ` Phillip Wood
2025-11-27 19:24 ` Siddharth Asthana
2025-11-25 17:25 ` [PATCH 0/1] " Johannes Schindelin
2025-11-25 18:02 ` Junio C Hamano
2025-11-26 19:18 ` Siddharth Asthana
2025-11-26 21:04 ` Junio C Hamano
2025-11-27 19:21 ` Siddharth Asthana
2025-11-27 20:17 ` Junio C Hamano
2025-11-28 8:07 ` Elijah Newren
2025-11-28 8:24 ` Siddharth Asthana
2025-11-28 16:35 ` Junio C Hamano
2025-11-28 17:07 ` Elijah Newren
2025-11-28 20:50 ` Junio C Hamano
2025-11-28 22:03 ` Elijah Newren
2025-11-29 5:59 ` Junio C Hamano
2025-12-02 20:16 ` [PATCH v2 0/2] replay: add --revert mode " Siddharth Asthana
2025-12-02 20:16 ` [PATCH v2 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2025-12-05 11:33 ` Patrick Steinhardt
2025-12-07 23:00 ` Siddharth Asthana
2025-12-08 7:07 ` Patrick Steinhardt
2026-02-11 13:03 ` Toon Claes
2026-02-11 13:40 ` Patrick Steinhardt
2026-02-11 15:23 ` Kristoffer Haugsbakk
2026-02-11 17:41 ` Junio C Hamano
2026-02-18 22:53 ` Siddharth Asthana
2025-12-02 20:16 ` [PATCH v2 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2025-12-05 11:33 ` Patrick Steinhardt
2025-12-07 23:03 ` Siddharth Asthana
2025-12-16 16:23 ` Phillip Wood
2026-02-18 23:42 ` [PATCH v3 0/2] " Siddharth Asthana
2026-02-18 23:42 ` [PATCH v3 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-02-20 17:01 ` Toon Claes
2026-02-25 21:53 ` Junio C Hamano
2026-03-06 4:55 ` Siddharth Asthana
2026-03-06 4:31 ` Siddharth Asthana
2026-02-26 14:27 ` Phillip Wood
2026-03-06 5:00 ` Siddharth Asthana
2026-02-18 23:42 ` [PATCH v3 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-02-20 17:35 ` Toon Claes
2026-02-20 20:23 ` Junio C Hamano
2026-02-23 9:13 ` Christian Couder
2026-02-23 11:23 ` Toon Claes
2026-03-06 5:05 ` Siddharth Asthana
2026-02-26 14:45 ` Phillip Wood
2026-03-06 5:28 ` Siddharth Asthana
2026-03-06 15:52 ` Phillip Wood
2026-03-06 16:20 ` Siddharth Asthana
2026-03-13 5:40 ` [PATCH v4 0/2] " Siddharth Asthana
2026-03-13 5:40 ` [PATCH v4 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-13 15:53 ` Junio C Hamano
2026-03-16 19:12 ` Toon Claes
2026-03-16 16:57 ` Phillip Wood
2026-03-13 5:40 ` [PATCH v4 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-16 16:57 ` Phillip Wood
2026-03-16 19:52 ` Toon Claes
2026-03-17 10:11 ` Phillip Wood
2026-03-16 16:59 ` [PATCH v4 0/2] " Phillip Wood
2026-03-16 19:53 ` Toon Claes
2026-03-24 22:03 ` [PATCH v5 " Siddharth Asthana
2026-03-24 22:04 ` [PATCH v5 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-24 22:04 ` [PATCH v5 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-25 6:29 ` Junio C Hamano
2026-03-25 15:10 ` Toon Claes
2026-03-25 15:38 ` Siddharth Asthana
2026-03-25 16:44 ` Phillip Wood
2026-03-25 15:36 ` Siddharth Asthana
2026-03-25 20:23 ` [PATCH v6 0/2] " Siddharth Asthana
2026-03-25 20:23 ` [PATCH v6 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-25 20:23 ` [PATCH v6 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
2026-03-28 4:33 ` Tian Yuchen
2026-03-29 16:17 ` Siddharth Asthana
2026-03-30 17:23 ` Tian Yuchen
2026-03-31 8:08 ` Toon Claes
2026-03-31 8:11 ` Toon Claes
2026-03-25 20:23 ` [PATCH v6 1/2] sequencer: extract revert message formatting into shared function Siddharth Asthana
2026-03-25 20:23 ` [PATCH v6 2/2] replay: add --revert mode to reverse commit changes Siddharth Asthana
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