Re: commit-graph overflow generation chicken and egg

[Derrick Stolee <derrickstolee@github.com>]

On 7/4/22 4:46 AM, Patrick Steinhardt wrote:
> On Fri, Jul 01, 2022 at 02:07:03PM +0200, Patrick Steinhardt wrote:

> While I still haven't been able to reproduce the error, I did find a
> different error. Here's the reproducer, which works with Git v2.37.0 and
> older:


Hi Patrick. Thanks for taking a close look. There is
an issue here, and it's due to using a negative
timestamp:

> + GIT_COMMITTER_DATE='1970-01-01T00:00:00 +0100'

Because of the "+0100" in the time zone, this date
becomes a negative value. The commit-graph does not
store dates with more than 34 bits (and Git does
not handle negative timestamps very well? Peff can
clarify here).

The commit-graph could certainly warn better here to
say we do not have enough date bits to store this
timestamp (the same would happen with a date beyond
2138 or something like that).

However, this is a failure since the commit-graph first
started parsing dates in 177722b3442 (commit: integrate
commit graph with commit parsing, 2018-04-10).

Thanks,
-Stolee