[PATCH 0/3] fix local_tzoffset with far-in-future dates

[Jeff King <peff@peff.net>]

On Mon, Jun 20, 2016 at 04:00:12PM -0400, Jeff King wrote:

> You _should_ be able to get the right answer by asking git for
> --date=local, but it doesn't seem to work. Looks like it is because our
> tm_to_time_t hits this code:
> 
>   if (year < 0 || year > 129) /* algo only works for 1970-2099 */
> 	return -1;
> 
> and the caller does not actually check the error. The resulting timezone
> is the screwed-up -40643156, which is perhaps how it got into the commit
> in the first place.

So here's a patch to fix that (along with some test infrastructure to
support it). I still don't know how that screwed-up timestamp got _into_
a commit, so perhaps there is another bug lurking.  I couldn't convince
git to parse anything beyond 2100, and committing with
GIT_AUTHOR_DATE='@5758122296 +0000' works just fine.

  [1/3]: t0006: rename test-date's "show" to "relative"
  [2/3]: t0006: test various date formats
  [3/3]: local_tzoffset: detect errors from tm_to_time_t

-Peff