Re: Bug in `git branch --delete main` when on other orphan branch

From: Martin von Zweigbergk <martinvonz@google.com>
Date: Nov 1, 2022, 15:31 UTC
Message-ID: <CAESOdVDmLxj2chGZzJYPjD6bw4XqWjjrPesc2ZCiE8JLPenADw@mail.gmail.com>
In-Reply-To: <Y2DxxZAFbN8juHY6@coredump.intra.peff.net>

On Tue, Nov 1, 2022 at 3:15 AM Jeff King <peff@peff.net> wrote:

Show 22 quoted lines

>
> On Fri, Oct 28, 2022 at 10:46:37PM -0700, Martin von Zweigbergk wrote:
>
> > I did this:
> > git init test
> > cd test
> > echo a > file
> > git add file
> > git commit -m a
> > git checkout --orphan other
> > git branch --delete main
> >
> > The last command fails with:
> > fatal: Couldn't look up commit object for HEAD
> >
> > That's a bug, right? I can of course work around it with `rm
> > .git/refs/heads/main`.
>
> Sort of. This is part of the "is the thing we are deleting merged into
> HEAD" check. It tries to look up the HEAD and calls die() when it can't.
> The more correct thing, I think, would be for it to just return "nope,
> there is no HEAD so nothing is merged into it".

Ah, so that's what it was about. Thanks for looking into it!

> And in the meantime, hopefully you noticed that "-f" is a better
> workaround than manually deleting the refs file. :)

Nope, because I had no idea it was something that could be first. Also, this was just in a script to reproduce an unrelated (non-Git) bug, so my hacky workaround was okay :)

Thanks!