Re: Question: How to find the commits in the ancestry path of seen down to _and_ including a given topic?

From: Derrick Stolee <derrickstolee@github.com>
Date: Jul 22, 2022, 11:06 UTC
Message-ID: <8315230c-f79c-8027-9711-6e21a4bc25c4@github.com>
In-Reply-To: <CABPp-BEqWX3Nr2HDxwS9d-_QjcKb_jS=fSjsP_Pbutw7-P5gbg@mail.gmail.com>

On 7/21/22 3:34 PM, Elijah Newren wrote:

Show 27 quoted lines

> On Thu, Jul 21, 2022 at 8:37 AM Junio C Hamano <gitster@pobox.com> wrote:
>>
>> Elijah Newren <newren@gmail.com> writes:
>>
>>> A simple question that I'm spinning out of [1]: How can I get `git
>>> log` to show the commits in the ancestry path from seen, back to *and
>>> including* a given topic (but not commits from unrelated topics)?
>>
>> Drawing of a sample history, please.
>>
>> I feel stupid asking this, but I do not think I even understand what
>> the question is X-<.
>>
>> Commits that are ancestors of 'seen' and are descendants of the tip
>> of the topic?
> 
> What you said *plus* commits from the topic itself.  From this graph:
> 
>     A---B---C---J---K <-- main
>             |\       \
>             | \       N---------------O---P---Q <-- seen
>             |  \     /               /
>             |   L---M  <-- topic    /
>              \                     /
>               D---E---F---G---H---I  <-- other_topic
> 
> I want the commits L-Q.  If I run

Here is the thing I misunderstood. "topic" is already in "seen", so a seen...topic won't work at all.

This idea is complicated by the fact that you have a concrete idea of which commits are in "topic", but you really can't do that without a definition of what it's based on. $(git merge-base main topic) would get you C, but then there are multiple paths from Q to C that don't go through topic.

You can pull out that "first" commit in topic with this:

  git revlist -1 --reverse main..topic

but it only works if topic is a linear branch off of a single point in the history of main.

Show 6 quoted lines

> The closest I seem to be able to get is
> 
>    git log --ancestry-path topic~${commits_in_topic_minus_one}..seen
> 
> which includes all commits I want except the first commit of the topic
> branch.

If you add --boundary, you should get that last commit as you want.

Thanks, -Stolee