Re: Revision walking, commit dates, slop

> Derrick Stolee <stolee@gmail.com> writes:
>> On 5/20/2019 7:02 AM, Jakub Narebski wrote:
>>>
>>> Are there any blockers that prevent the switch to this
>>> "generation number v2"?
>>> 
>>> - Is it a problem with insufficient data to choose the correct numbering
>>>   as "generation number v2' (there can be only one)?
>>> - Is it a problem with selected "generation number v2" being
>>>   incompatibile with gen v2, and Git failing when new version of
>>>   commit-graph is used instead of softly just not using commit-graph?
>>> - Or is it something else?

>>                      Using the generation number column for the corrected
>> commit-date offsets (assuming we also guarantee the offset is strictly
>> increasing from parent to child), these new values will be backwards-
>> compatible _except_ for 'git commit-graph verify'.
>
> O.K., so the "generation number v2 (legacy)" would be incremental and
> backward-compatibile in use (though not in generation and validation).
>
> Do I understand it correctly how it is calculated:
>
>   corrected_date(C) = max(committer_date(C),
>                           max_{P ∈ parents(C)}(corrected_date(P)) + 1)
>   offset(C) = corrected_date(C) - committer_date(C)
>   gen_v2(C) = max(offset(C), max_{P ∈ parents(C)}(gen_v2(P)) + 1)