From: Junio C Hamano <gitster@pobox.com>
Date: Thu, 15 Nov 2007 08:00:45 GMT
Subject: [Discussion] cherry-picking a merge
Message-ID: <7v3av86iqa.fsf@gitster.siamese.dyndns.org>

Earlier "git cherry-pick" learned the "-m <parent-number>"
option to allow cherry-picking a merge commit.

When you have this history:

  ---o---o---C---A---M
      \             /
       o---o-------B

You can replay the change between A and M (in other words, the
effect of merging B into A) on top of C to create a new commit,
with:

        $ git cherry-pick -m 1 M

In the current implementation, the resulting commit has a single
parent C.  This is quite similar to a squash merge of B into C.

When you think about it, as long as the topological relationship
between A and B is very similar to that of C and B (iow,
"merge-base A B" and "merge-base C B" are the same), the effect
should be the same as a real merge between B and C, shouldn't it?

  ---o---o---C---A---M
      \       \     /
       o---o---\---B
                \   \
                 `---X

I am wondering if it makes sense to record the result of
"cherry-pick -m" as a real merge between the current HEAD and
all the other parents of the cherry-picked merge except the one
that is named with the <parent-number>.