Re: git rebase crash: merge-ort.c:2622: apply_directory_rename_modifications: Assertion `ci->dirmask == 0' failed.

From: Elijah Newren <newren@gmail.com>
Date: Oct 22, 2022, 19:06 UTC
Message-ID: <CABPp-BFEg861ru2mJujnHLCD29WNgp4C6f8+CvL6vFRS6r5NLQ@mail.gmail.com>
In-Reply-To: <CABPp-BGdGZ6dg4_wWxkz+VCvaThfn3eL9uqBvmsK3+8GQf0ByA@mail.gmail.com>

Hi,

On Tue, Sep 20, 2022 at 12:15 AM Elijah Newren <newren@gmail.com> wrote:

Show 29 quoted lines

>
> Hi,
>
> On Fri, Sep 16, 2022 at 6:24 AM Stefano Rivera <stefano@rivera.za.net> wrote:
> >
> > Hi, I got a crash in git-rebase, a failed assertion in merge-ort.c
> >
> > $ git rebase renamed-parent
> > git: merge-ort.c:2622: apply_directory_rename_modifications: Assertion `ci->dirmask == 0' failed.
> >
> > I was rebasing a branch that replaced a directory with a symlink, onto a
> > branch that renamed a parent directory of the modification.
> >
> > Reproducer script attached.
> >
> > Using --strategy=recursive avoids the crash, so it's a bug in ort.
> >
> > Not subscribed, please CC me in replies.
> >
> > Thanks,
> >
> > SR
> >
>
> Thanks for testing out a release candidate, typing up the detailed
> report, and even finding a simple testcase!  Very cool.
>
> I don't have a fix, but just wanted to send a note out that I've seen
> your report and will take a look at it this week.

I had a hacky fix for about a month now, and haven't had time to clean it up and look around for nearby issues.

I believe the cause here is related to the code added to fix the bug in 902c521a35 ("t6423: more involved directory rename test", 2020-10-15). Since that issue was never fixed in merge-recursive, it didn't get the side effect of this new bug. Had that other bug been fixed in merge-recursive, it may well have exhibited a similar issue with the testcase you reported here.

Anyway, I posted a patch to fix this issue in ort: https://lore.kernel.org/git/pull.1391.git.1666465450590.gitgitgadget@gmail.com

Thanks again for reporting it, and for providing the simple steps to reproduce!