Re: BUG: commit-reach.c:66: bad generation skip

[Junio C Hamano <gitster@pobox.com>]

Derrick Stolee <stolee@gmail.com> writes:

> On 2/10/2021 7:18 AM, Filippo Valsorda wrote:
>> On Mon, Feb 8, 2021 at 3:26 AM Derrick Stolee <stolee@gmail.com> wrote:
>>> _This_ is interesting. I haven't heard of this problem happening
>>> in a released version of Git.
>>>
>>> I'm CC'ing Jonathan Nieder who recently saw this happening, but that
>>> was on a newer version than 2.30.0 with a topic that is not part
>>> of 2.30.0. But maybe the version shipped internally is versioned
>>> without extra information on top of the latest tag? (I see your
>>> @google.com email, which makes me think you have an internal version.)
>> 
>> Ah, the issue indeed first showed up as I was using the internal
>> version. I then installed mainline 2.30.0 to check that it reproduced
>> on the same local repository before reporting a bug.
>
> The mainline does have the BUG() statement, but it's really reflecting
> bad data in the commit-graph file. That data was written by the internal
> version and was not reset until you rewrote the file.

Thanks for digging, you two.  The above clearly explains the
symptom.

> Thanks, but let me know if it reproduces again. The bug should be fixed
> in ds/commit-graph-genno-fix [1], and I think the Google internal release
> has been rolled back until that branch is included.

The topic has been cooking in 'next' since Feb 3rd, so jrnieder's
team would probably have already picked it up.  It would be in
'master', together with the ak/corrected-commit-date topic it builds
on, not in a very distant future (typically a topic cooks in 'next'
for a week, unless it is a trivial typofix, doc updates, that sort
of low-impact change).

Thanks.