How to find the first commit belonging to any branch

> I have a question about git: I have one commit sha1, and I would like
> to know the nearest commit that appears in *any* other branch. The
> sha1 that I have does not belong to any branch.
>
> The obvious thing to do would be to make a for loop and iterate over
> existing branches while calling git merge-base, but I'm wondering if
> there's a more clever method.

> Kristian Amlie <kristian.amlie@trolltech.com> writes:
> 
>> I have a question about git: I have one commit sha1, and I would like
>> to know the nearest commit that appears in *any* other branch. The
>> sha1 that I have does not belong to any branch.
>>
>> The obvious thing to do would be to make a for loop and iterate over
>> existing branches while calling git merge-base, but I'm wondering if
>> there's a more clever method.
> 
> If the $commit does not belong to any branch, then:
> 
>     $ git rev-list --bounardy $commit^0 --not --branches | sed -ne 's/^-//p'
> 
> would give you boundary commits of the above traversal, which says:
> 
>     Traverse from $commit following the parents, but stop at anything that
>     is reachable from any breanch.
> 
> which means that the ones that are output are the candidates that are on
> some branch.
> 
> So pipe that to name-rev like this, perhaps (untested)?
> 
>     $ git rev-list --bounardy $commit^0 --not --branches |
>       sed -ne 's/^-//p' |
>       git name-rev --stdin
> 
>