Re: [PATCH] add receive.denyNonFastforwards config variable

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sep 21, 2006, 09:08 UTC
Message-ID: <Pine.LNX.4.63.0609211103130.19042@wbgn013.biozentrum.uni-wuerzburg.de>
In-Reply-To: <7vbqp9d8j2.fsf@assigned-by-dhcp.cox.net>

Hi,

On Wed, 20 Sep 2006, Junio C Hamano wrote:

Show 22 quoted lines

> Jeff King <peff@peff.net> writes:
> 
> >>     X - a - b - c - Y
> >>   /           /
> >> o - d - e - f
> >
> > In your example, git-merge-base X Y returns X. In fact, I could only get
> > one merge base out of git-merge-base --all. I tried looking in the tests
> > to find a case that produced multiple merge bases, but I was unable to
> > find one. Is there an example floating around somewhere?
> 
> There are quite a few in git.git itself.  In the recent history,
> this counts 42, the answer to everything.
> 
> #!/bin/sh
> LF='
> '
> git rev-list --parents master..next |
> while read it p1 p2 octo
> do
> 	case "$p2" in '') continue ;; esac
>         mb=`git merge-base --all "$p1" "$p2"`

At this point you should also check if $p2 is in $mb.

> 	case "$mb" in ?*"$LF"?*) echo "$p1 $p2" : $mb ;;
>         esac
> done

The question was, if there is a fast-forward with more than one merge base, i.e. if the loop we jump^H^H^H^Hdo over bases is necessary.

And no, I am not aware of any such example.

Probably because X would mark all ancestors (_including_ all other possible merge bases) as uninteresting.

Therefore, I am convinced that there is no fast-forward returning more than one merge base. It is technically impossible. And thus, our loop is not necessary, but what the heck.

Ciao, Dscho