Re: how to undo a git merge?

From: Jakub Narebski <jnareb@gmail.com>
Date: Jul 11, 2008, 18:36 UTC
Message-ID: <200807112036.13745.jnareb@gmail.com>
In-Reply-To: <fa7d16350807111108y3a8a7c3di19598a56dbbcdc15@mail.gmail.com>

ff (?) wrote:

> 
> I did see the -m option in the revert man page. It talks about
> "parent" and I did not understand what that is. Is parent the commit
> id of the merge commit?

It is _number_ of parent.

   -m parent-number, --mainline parent-number
          Usually you cannot revert a merge because you do not know which side
          of  the  merge should be considered the mainline. This option speci-
          fies the parent number (starting from 1) of the mainline and  allows
          revert to reverse the change relative to the specified parent.

Merge commit has more than one parent. What git-revert does, it creates commit which reverts the changes, as if applying "reversal" diff, "git diff -R <revision>^<parent-number> <revision>".

-- 
Jakub Narebski
Poland