Re: [PATCHv2 2/2] pull: support rebased upstream + fetch + pull --rebase

> 2009/7/17 Santi Béjar <santi@agolina.net>:
>> 2009/7/16 Junio C Hamano <gitster@pobox.com>:
>>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>>
>>>> How about
>>>>
>>>>       oldremoteref="$(git rev-list --boundary HEAD --not \
>>>>                       $(git rev-list -g $remoteref | sed 's/$/^@/') |
>>>>               sed -e '/^[^-]/d' -e q)"
>>>>
>>>> Explanation: the "git rev-list -g $remoteref" lists the previous commits
>>>> the remote ref pointed to, and the ^@ appended to them means all their
>>>> parents.  Now, the outer rev-list says to take everything in HEAD but
>>>> _not_ in those parents, showing the boundary commits.  The "sed" call
>>>> lists the first such boundary commit (which must, by construction, be one
>>>> of the commits shown by the first rev-list).
>>>
>>> Hmm, I am not sure about that "(which must..." part.
>
> Unfortunatly you are right with the "(which must..." part. Even
> without the ^@. Normally gives the right answer, but it is not
> sure that the first commit boundary is the correct one. For
> example:
>
>          o--C
>         /
>  A--x--y--B--o--z
>      \      /
>       o----o
>
> A, B, C are upstream@{n}
>
> It involves a merge with a branch forked before the fork commit
> for the current branch, and it will not work neither with git
> pull --rebase. We could say that it is not supported, but
> nevertheless it gives the wrong answer.
>
> The right answer is B, but:
> $ git rev-list --boundary z --not C B A
> z
> o
> o
> o
> -x
> -B