From mboxrd@z Thu Jan  1 00:00:00 1970
From: Junio C Hamano <junkio@cox.net>
Subject: Re: [PATCH] add receive.denyNonFastforwards config variable
Date: Wed, 20 Sep 2006 22:08:28 -0700
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To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
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Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> On Wed, 20 Sep 2006, Junio C Hamano wrote:
>
>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>=20
>> > 	No longer barfs on new refs, and tries all merge bases (even if I
>> > 	cannot come up with any scenario where there is more than one mer=
ge
>> > 	base in the case of a fast forward).
>>=20
>> Hmm.  If that is the case (and I think it is although I haven't
>> come up with a proof),
>
> From git-fetch.sh:
>
>             # Require fast-forward.
>             mb=3D$(git-merge-base "$local" "$2") &&
>...
> So we indeed assumed that git-merge-base returns the old commit in th=
e=20
> case of a fast-forward (git-merge-base returns just the first item of=
 the=20
> result of get_merge_bases()).

I think this was leftover from the days we na=EFvely assumed that
multiple bases does not matter, and probably needs updating.

> Note that I have no proof that this assumption is true. It might be w=
rong=20
> in this case:
>
>     X - a - b - c - Y
>   /           /
> o - d - e - f
>
> where X is the old commit, and Y is the new commit. But I am too tire=
d to=20
> test it right now.