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

[Norbert Kiesel <nkiesel@gmail.com>]

There are more strange things happening with dates.  One example is
that `git commit --date=@4102444799` produces a commit with the
correct author date "Thu Dec 31 15:59:59 2099 -0800" (for my local
timezone which is Americas/Los_Angeles), while `git commit
--date=@4102444800` produces a commit with "now" as author date, as
does any other larger number. `date --date=@4102444800` results in
"Thu Dec 31 16:00:00 PST 2099". So seems 2100-01-01T00:00:00Z is a
hard limit for git when using this format.

On Mon, Jun 20, 2016 at 3:21 PM, Jeff King <peff@peff.net> wrote:
> On Mon, Jun 20, 2016 at 03:11:23PM -0700, Junio C Hamano wrote:
>
>> Jeff King <peff@peff.net> writes:
>>
>> > 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.
>>
>> Interesting.  The weirdest I could come up with was with
>>
>>     GIT_AUTHOR_DATE='@5758122296 -9999
>>
>> which gets turned into the same timestamp but with -10039 timezone
>> (simply because 99 minutes is an hour and 39 minutes).
>
> Yeah, as weird as that is, I think it's reasonable. We _could_ turn
> nonsense timezones into "+0000". That doesn't necessarily help the user
> much, but at least it's less bizarre than making a 46-year timezone
> offset.
>
> I also looked for other uses of tm_to_time_t without checking for an
> error return. Most of them do check. The exception is datestamp(), but
> is calling it on the output of localtime(time()), which should generally
> be sensible.
>
> -Peff