Re: [PATCH 00/26] git-log: implement new --diff-merge options

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 9, 2020, 01:17 UTC
Message-ID: <xmqqtusv4w2g.fsf@gitster.c.googlers.com>
In-Reply-To: <CABPp-BE3D7ifQx6MZCT_ntRnG0QZm1Ga10SJ=DN+6bpF6mX2GQ@mail.gmail.com>

Elijah Newren <newren@gmail.com> writes:

> ... I guess I'm not sure why one would ever
> want to see diffs for merges and not for normal commits.  Even in the
> unusual case someone did, couldn't they just pass --merges (to strip
> out the normal commits entirely)?

Giving "--merges" would skip the single-strand-of-pearls commits entirely, not even showing their log messages, so it won't be an equivalent substitute.

Show 5 quoted lines

> Honestly, I find it a little surprising that despite the fact that log
> -p shows nothing for merge commits, that when I add --first-parent to
> see a subset of commits I suddenly get weird, huge diffs shown for the
> merges (yeah, yeah, I learned recently that it's documented behavior,
> so it's not surprising anymore, just weird).

I view "--first-parent" as telling "git log" to pretend all merges are single-parent commits (as if you did squash merges), and it is a natural consequence if "log --first-parent -p" showed each commit with its first parent, whether it is a merge or a single-parent commit.