Re: [BUG] Highly inconsistent diff UI

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 24, 2013, 21:23 UTC
Message-ID: <7vvc7baahc.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CALkWK0m5Q_e3q6Yg94-K+jU_SS7ovR2wnz-_Nr3cMz_YM=SMDQ@mail.gmail.com>

Ramkumar Ramachandra <artagnon@gmail.com> writes:

Show 5 quoted lines

> Sorry I wasn't clear.  A~B = $(git merge-base A B) B to diff and $(git
> merge-base A B)..B to log.
>
> Basically, I want to be able to do git log master~rebase.autostash
> (without having to rebase).

How is it different from "git log master..rebase.autostash"?

    git log A..B

is already a perfectly fine way to spell your "A~B", which is

    git log B --not $(git merge-base --all A B)

when written in longhand [*1*], no?

So I do not think your A~B helps "log".

It does not help "diff" either, because we already have A...B and we are not going to remove it (people are used to what it means).

So I think your A~B is still a solution that is looking for a problem.

[Footnote]

*1* You need to understand what merge-base is in order to analyse
    the equivalence of these two.  A..B asks for those that are
    reachable from B that are not reachable from A.  What does the
    other form ask, by saying "ones that can be reached from B but
    exclude the ones that are reachable from any merge base of A and
    B"?

    On the history leading to A, there are two kinds of commits:
    those that are not reachable from B and those that are.  The
    ones closer to A may not be reachable from B but if you dig the
    history starting from A and keep finding ancestors, you will
    eventually hit one that can be reached from B.  Once you hit
    such a commit, everything beyond that point are reachable from
    both A and B.  E.g.

        ---o---*---a---a---a---A
                \
                 b---b---B

    And we call that a merge base between A and B (e.g. '*').  Any
    ancestor of a merge base, e.g. 'o', is reachable from A and is
    excluded from "A..B".