From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 24 Apr 2019 01:05:54 GMT
Subject: Re: [PATCH] revisions.txt: mention <rev>~ form
Message-ID: <xmqqh8ao43gt.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <CACsJy8DB3k=9PaQT4CBz-K3=yjQ1oJAtz6p00PAOjy047XvAyA@mail.gmail.com>

Duy Nguyen <pclouds@gmail.com> writes:

> On Mon, Apr 22, 2019 at 1:14 PM Denton Liu <liu.denton@gmail.com> wrote:
>>
>> In revisions.txt, the '<rev>^' form is mentioned but the '<rev>~' form
>> is missing. Although both forms are essentially equivalent (they each
>> get the first parent of the specified revision), we should mention the
>> latter for completeness. Make this change.
>
> Do we really support this, or is it a bug in rev parsing code that
> treats <rev>~ like <rev>~1?
>
> Hmm.. digging... ah 621ff67594 (rev-parse: fix meaning of rev~ vs
> rev~0., 2008-03-14) at least it's not an unintended bahaviour.

commit 621ff6759414e2a723f61b6d8fc04b9805eb0c20
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri Mar 14 11:49:40 2008 -0700

    rev-parse: fix meaning of rev~ vs rev~0.
    
    I think it would make more sense for rev~ to have the same guarantees that
    rev^ has, namely to always return a commit. I would also suggest that not
    giving a number would have the same effect of defaulting to 1, not 0.

Yes, I remember that one: if rev^ means rev^1, rev~ should mean
rev~1, not rev or rev~0.