Re: Find the starting point of a local branch

[Nguyen Thai Ngoc Duy <pclouds@gmail.com>]

On Tue, Dec 25, 2012 at 2:10 AM, Junio C Hamano <gitster@pobox.com> wrote:
>> I looked briefly at reflog before writing my previous mail and noticed
>> that when I create a new branch (usually using "git checkout -b branch
>> ref") it does not record the base commit.
>
> Hmph.  Perhaps you are referring to something different than what I
> think "the base commit" with that word.
>
>     $ git reflog mz/pick-unborn | tail -n 1
>     b3cf6f3 mz/pick-unborn@{3}: branch: Created from ko/master

No you're right. My reflogs must be pruned. Creating a new branch does
produce that entry.

>> We could at least invalidate the recorded base in reflog and let user
>> define a new one (I hope).
>
> Please do not even think about going back and rewrite to lose
> information.  If the records have full information, you should be
> able to reconstruct what you want from it without rewriting.
>
> Even more importantly, wish to "invalidate" indicates that you know
> at a newer point that you have more authoritative information than
> the older reflog entries, so you should be able to do the moral
> equivalent by writing the event as establishing a new base at that
> point (e.g. "checkout -B"), and stopping at that point in the reflog
> when reading, without losing the older reflog entries.

Exactly. And when we prune the reflog, we could add the base back so
the base is always in reflog.
-- 
Duy