Re: Merging adjacent deleted lines?

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 21, 2009, 21:08 UTC
Message-ID: <7vy6x4cqq1.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <57518fd10901211120n62f8d0e9ya8595fc9baa6476c@mail.gmail.com>

Jonathan del Strother <maillist@steelskies.com> writes:

Show 28 quoted lines

> Say I have a file that started out with the following content :
>
> line1
> line2
> line3
> line4
>
>
> I create a branch, which deletes line2.  Someone else's branch deletes line 3.
>
> When I merge those two branches, the conflict looks like :
>
> line1
> <<<<<<< HEAD:lines
> line3
> =======
> line2
>>>>>>>> SomeoneElse:lines
> line4
>
>
>
> Which in my cursory overview, looked an awful lot like the obvious
> merge resolution ought to be
>
> line1
> line3
> line4

Why?  The obvious resolution would be:

    line1
    line4

as it is obvious that you do not want line2 and the other does not want line3.

But that is only true if it is obvious to you. When you cannot remember what each side did since they forked, there are two ways you can use to understand the history better without resorting to graphical merge tools.

  $ git log -p --merge <path>

which shows you the commits involved in the conflict, what they did, and why they did what they did (of course, this assumes that your project participant did their commits properly).

  $ git checkout --conflict=diff3 <path>

This will add an extra block to the conflicted output to show the common ancestor's version, after showing yours. The conflicts left in <path> would look like this:

    line1
    <<<<<<< ours
    line3
    |||||||
    line2
    line3
    =======
    line2
    >>>>>>> theirs
    line4

which may make it clearer that you deleted line2 and they deleted line3.