Re: Find the starting point of a local branch

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 24, 2012, 06:27 UTC
Message-ID: <7vmwx4newy.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CACsJy8DkA-J+ds1eHBqrRyiZrOigORTtxVeEQpZjGHrBR+QjCQ@mail.gmail.com>

Nguyen Thai Ngoc Duy <pclouds@gmail.com> writes:

Show 11 quoted lines

> On Mon, Dec 24, 2012 at 12:34 PM, Tomas Carnecky
> <tomas.carnecky@gmail.com> wrote:
>>> Maybe we should store this information. reflog is a perfect place for
>>> this, I think. If this information is reliably available, git rebase
>>> can be told to "rebase my whole branch" instead of my choosing the
>>> base commit for it.
>>
>> What's the starting point of the branch if I type: git branch foo <commit-ish>?
>
> You start working off <commit-ish> so I think the starting point would
> be <commit-ish>.

Yeah, that sounds sensible. Don't we already have it in the reflog, though?

What is trickier is when you later transplant it to some other base (perhaps prepare a topic on 'master', realize it should better apply to 'maint' and move it there). If the user did the transplanting by hand, reflog would probably not have enough information, e.g. after

    $ git checkout maint^0
    $ git log --oneline master..topic
    $ git cherry-pick $one_of_the_commit_names_you_see_in_the_above
    $ git cherry-pick $another_commit_name_you_see_in_the_above
      ...
    $ git branch -f topic

no reflog other than HEAD@{} will tell you that you were at maint^0, so the reflog of topic wouldn't know it "forked" from there, either.