From: Lynn Lin <lynn.xin.lin@gmail.com>
Date: Sat, 10 Sep 2011 01:11:42 GMT
Subject: Re: merge result
Message-ID: <CAPgpnMTMPQQPkS-gKLvUJNKLfMWuAT-oA3NCiSRFxu7PknYsnA@mail.gmail.com>
In-Reply-To: <vpqmxed6fby.fsf@bauges.imag.fr>

On Fri, Sep 9, 2011 at 9:00 PM, Matthieu Moy
<Matthieu.Moy@grenoble-inp.fr> wrote:
> Lynn Lin <lynn.xin.lin@gmail.com> writes:
>
>> Hi All,
>>    When I merge branch A back to master branch,if there are same
>> commit(developer do double commit) both in master and A branch, there
>> will be two same commit in master branch.
>
> They cannot be the "same" commit. They are different commits (i.e.
> different sha1 identifier, and probably different trees), even though
> they may have the same commit message and represent the same diff.
>
>>    1->2->3-4>5        Master
>>        |
>>        4->6->7          A
>
> A more accurate drawing would be
>
>    1->2->3-4>5        Master
>        |
>        4'->6->7          A
>
> and after merging, you'd get
>
>    1->2->3-4>5-->8  A, master
>        |       /
>        4'->6->7
>
> with 8 having both 4 and 4' as ancestors. There's nothing wrong with it.
> Git cannot remove either 4 or 4' without rewritting history, and "git
> merge" does not rewrite history.
so confused here.If 4' is just next 4 commit,how can the diff work? for example

1->2->4->4'->6->...

 diff 4 and 4' is a little confused,correct?


Thanks for your time to explain here and teach me

> If you really really want to avoid this duplication in the history, then
> learn about rebase (which is both powerfull and dangerous, you've been
> warned).
>
> --
> Matthieu Moy
> http://www-verimag.imag.fr/~moy/
>