Re: Have git-merge-base support multiple IDs

From: Michael J Gruber <git@drmicha.warpmail.net>
Date: Aug 3, 2009, 21:52 UTC
Message-ID: <4A775C20.9070109@drmicha.warpmail.net>
In-Reply-To: <alpine.LSU.2.00.0908031539070.2603@fbirervta.pbzchgretzou.qr>

Jan Engelhardt venit, vidit, dixit 03.08.2009 15:39:

Show 23 quoted lines

> 
> On Friday 2009-07-31 18:22, Michael J Gruber wrote:
>> Jan Engelhardt venit, vidit, dixit 31.07.2009 17:51:
>>> To determine the rebase point (i.e. first commit in a series),
>>> one can (ab)use git-merge-base:
>>>
>>>   p=$(git merge-base ab80794f faae2553)
>>>   git re -i ${p}^
>>>
>>> The twist is that merge-base in git 1.6.3.3 happens to ignore any 
>>> further arguments following two IDs. In short:
>>>
>>>   git merge-base A B C...
>>>
>>> Only yields the merge-base of A and B, and ignores C...
>>
>> Uhm, are you sure about this?
>> The first argument is special. merge-base computes the merge base between two commits:
>> - the first argument
>> - a (hypothetical) merge between all other arguments.
>> It may look a if C was ignored, though.
> 
> Hm indeed. Is there a better way to find the common ancestor of commits?

I haven't tested thorougly, but at least for the standard example

git show-branch --merge-base A B C

seems to do what you want. Note that for this command, the order of arguments is irrelevant, whereas for git merge-base it makes a huge difference. Also, git show-branch documentation is a bit outdated. I expect to look into this...

Michael