From: Siddharth Asthana <siddharthasthana31@gmail•com>
To: Junio C Hamano <gitster@pobox•com>
Cc: git@vger•kernel.org, christian.couder@gmail•com, ps@pks•im,
newren@gmail•com, phillip.wood123@gmail•com,
phillip.wood@dunelm•org.uk, 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: Fri, 28 Nov 2025 00:53:46 +0530 [thread overview]
Message-ID: <78e31e24-5eab-44d8-a7e0-d3efae6ca6cf@gmail.com> (raw)
In-Reply-To: <xmqq8qfsmraa.fsf@gitster.g>
On 27/11/25 02:43, Junio C Hamano wrote:
> Siddharth Asthana <siddharthasthana31@gmail•com> writes:
>
>>>> +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.
>>> Is there any topological requirement between 'main' and 'feature'
>>> branches?
>> Yes, and I failed to explain this. For reverts to produce meaningful
>> non-empty commits, the commits being reverted should already be in the
>> target branch's history. I will clarify the examples to show this
>> topology requirement explicitly.
> We need to be a bit careful, though. Strictly speaking, what we
> have is not a requirement on the shape of the history.
Right - it's the changes that need to exist in the target tree, not the
commits themselves. Cherry-picked commits can be reverted even without
topological ancestry. I will fix the documentation.
> If a topic
> that was merged to the development branch gets cherry-picked to the
> master branch, and then it turns out to be faulty and needs to be
> reverted, we can still "revert" the original topic out of the master
> branch, even though topologically, the original topic is *not* in
> 'master'.
>
>>>> + /* For revert: swap base and pickme to reverse the diff */
>>>> + merge_opt->branch1 = short_commit_name(repo, replayed_base);
>>>> + merge_opt->branch2 = xstrfmt("parent of %s", short_commit_name(repo, pickme));
>>> That is an overly long line (sorry, I notice these things when a
>>> line does not even fit in 92-col terminal).
>>
>> Fixed in my local tree by introducing a `pickme_name` variable.
> Just a line-folding at an appropriate column may be sufficient, e.g.,
Will do.
>
> merge_opt->branch2 = xstrfmt("parent of %s",
> short_commit_name(repo, pickme));
>
>>>> - free((char*)merge_opt->ancestor);
>>>> merge_opt->ancestor = NULL;
>>>> + merge_opt->branch2 = NULL;
>>> Not a new problem, but what is the point of setting these two (but
>>> not branch1) to NULL?
>>
>> You're right, this is inconsistent. The intent is to prevent
>> use-after-free, but setting only some fields to NULL is incomplete. I
>> will either set all three to NULL or add a comment explaining the rationale.
> Is this the only place that resets a subset of merge_opt members for
> reuse? If not, are these multiple places want to reset the same
> subset of the members? Perhaps we can use a helper function to
> clarify in such a case.
This is the only place in replay.c. The reason we only NULL ancestor and
branch2 is that those are the ones allocated with xstrfmt() - branch1
points to short_commit_name() which doesn't need freeing.
A helper would make the intent clearer. I will look into adding one.
Thanks,
Siddharth
next prev parent reply other threads:[~2025-11-27 19:23 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 [this message]
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
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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