Re: [PATCH] bisect: fix "reset" when branch is checked out elsewhere

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 6, 2023, 19:04 UTC
Message-ID: <xmqqwn4u7gyt.fsf@gitster.g>
In-Reply-To: <a66218a3-919d-eca2-1859-41ac02aa38e7@gmail.com>

Rubén Justo <rjusto@gmail.com> writes:

> The devil is in the details: "git branch -m", "git branch -d".
>
> We're not ready to have BISECT_START pointing to a deleted branch, or
> renaming a branch pointed by it.

It indicates that the callers of find_shared_symref() to see if "is this branch being actively used by checked out, bisected, or rebased, and I shouldn't touch it?" need to know more than what find_shared_symref() interface gives them---namely, "can I repoint it to a different commit?" and "can I make it disappear?" are different conditions they need to be able to learn.

Until that distinction becomes expressible, I am actually OK with forbidding both operations, i.e. while a branch is being bisected elsewhere, we should be able to update its tip to point at a different commit, but it is OK to forbid that because we cannot allow the branch be renamed away or removed.

Thanks.