Re: [ANNOUNCE] Git v2.20.0-rc1

From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [ANNOUNCE] Git v2.20.0-rc1
Date: Mon, 26 Nov 2018 23:52:22 +0100 (STD)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.1811262347360.41@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <877eh219ih.fsf@evledraar.gmail.com>

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Hi Ævar,

On Sat, 24 Nov 2018, Ævar Arnfjörð Bjarmason wrote:

> On Wed, Nov 21 2018, Junio C Hamano wrote:
> 
> >  * "git rebase" and "git rebase -i" have been reimplemented in C.
> 
> Here's another regression in the C version (and rc1), note: the
> sha1collisiondetection is just a stand in for "some repo":
> 
>     (
>         rm -rf /tmp/repo &&
>         git init /tmp/repo &&
>         cd /tmp/repo &&
>         for c in 1 2
>         do
>             touch $c &&
>             git add $c &&
>             git commit -m"add $c"
>         done &&
>         git remote add origin https://github.com/cr-marcstevens/sha1collisiondetection.git &&
>         git fetch &&
>         git branch --set-upstream-to origin/master &&
>         git rebase -i
>     )
> 
> The C version will die with "fatal: unable to read tree
> 0000000000000000000000000000000000000000". Running this with
> rebase.useBuiltin=false does the right thing and rebases as of the merge
> base of the two (which here is the root of the history).

Sorry, this bug does not reproduce here:

$ git rebase -i
Successfully rebased and updated refs/heads/master.

> I wasn't trying to stress test rebase. I was just wanting to rebase a
> history I was about to force-push after cleaning it up, hardly an
> obscure use-case. So [repeat last transmission in
> https://public-inbox.org/git/87y39w1wc2.fsf@evledraar.gmail.com/ ]

Maybe you can give me the full details so that I can verify that this is
indeed a bug in the builtin C and not just a regression caused by some
random branches being merged together?

In short: please provide me with the exact URL and branch of your git.git
fork to test. Then please make sure to specify the precise revision of the
sha1collisiondetection/master rev, just in case that it matters.

Ideally, you would reduce the problem to a proper test case, say, for
t3412 (it seems that you try to rebase onto an unrelated history, so it is
*vaguely* related to "rebase-root").

Ciao,
Dscho