Re: Emacs git repo mangled

[Michael Albinus]

Gregory Heytings <gregory@heytings.org> writes:

Hi Gregory,

>>> + Depending on what you want to do, it can be helpful to use the option
>>> + '--first-parent' with 'git bisect', which makes bisect ignore commits
>>> + coming into a branch from merges.
>>
>> I'd rather say 'git start --first-parent'. There's no other bisect
>> subcommand with that option.
>
> Doing that is wrong, alas.  Limiting bisection to first parents will
> often produce a wrong result.  TRT here is to follow Linus' advice, to
> which I pointed in my other post, namely to manually mark the last
> commit of the eglot branch before it was merged as "good".

This approach would raise other problems.

- You might not know that you are in a merged subtree. It took me two
  days until I realized this (hmm, this could mean I'm too stupid).

- If the bad commit is inside the merge, you won't see it, because you
  have marked the whole merged subtree as good (by marking the last
  commit of the merged subtree).

- It would require manual actions, because first you need to determine
  the range of the merged subtree in order to mark last commit of this.

Best regards, Michael.