Re: [BUG] Git bisect extends bisecting range on repeated good/bad data

> On Dec 13, 2019, at 9:58 PM, Junio C Hamano <gitster@pobox.com> wrote:
> 
> Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org> writes:
> 
>> Git bisect may /extend/ bisection range on repeated good/bad data.  Is this expected?
> 
> It is not "repeated" that is an issue, but yes this is expected.
> 
> The bisection works by finding a mid point to cut the graph into two
> pieces of roughly the same size, and the graph is defined by the
> set of good commits on the bottom (i.e. "we were told that all these
> good commits were good, so there is no point going back the history
> beyond any of them") and the single "bad" commit you gave the last.
> 
> If you give 'bad' that is in the newer part of the history than the
> one that is already known to be bad, then you rewind that single
> "bad" commit, to force/allow the machinery to recompute the midpoint
> [*1*], and because the area to search would be wider when you do so,
> it is very much expected that you'd be offered to test more commits.
> 
> 
> 
> [Footnote]
> 
> *1* I said force/allow is because allowing the machinery to go back
>    and recompute is a way to recover when you gave a "bad" earlier
>    by mistake.
>