Re: Allow git bisect to auto-skip

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 22, 2024, 22:31 UTC
Message-ID: <xmqqwmptzyny.fsf@gitster.g>
In-Reply-To: <3d835c4b-d026-4c6a-b68e-6989a7a2065f@schinagl.nl>

Olliver Schinagl <oliver@schinagl.nl> writes:

Show 5 quoted lines

> In some cases, we know a commit will always break bisect. This is bad
> and evil but sometimes needed.
> ...
> git commit -m 'copy old to new' -m 'GIT_SKIP_BISECT'
> ...

If "I want a bisect to skip any commit that has 'Skip Me' in its subject" is the case, perhaps your "git bisect run" script can say

    #!/bin/sh

    case "$(git show -s --oneline)" in
    *"Skip Me"*) exit 125 ;;
    esac

    ... your test script body comes here ...
    if test successful
    then
        exit 0
    else
        exit 1
    fi

The _clue_ to mark a commit to be skipped does not have to be hardcoded commit title. It often is discovered that a commit breaks bisection after the fact and it is not feasible to rebase all the history after the commit. Maybe an approach more suitable in such a situation would attach a note to such untestable commits after the fact, and check if such a note is attached at the beginning of "git bisect run" script and exit with 125.

And a new "git bisect --skip-when <condition>" option can be added to manual bisection process. The <condition> part would contain something like

    case "$(git show -s --oneline)" in
    *"Skip Me"*) exit 125 ;;
    esac

taken from the above illustration.

But I am not sure what end result you are trying to achieve, so the above are random collection of ideas. Turning them into a patch is left as an exercise to readers.