From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Andreas Schwab <schwab@linux-m68k.org>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: [ANNOUNCE] Git v2.9.1
Date: Tue, 12 Jul 2016 11:35:20 -0400 [thread overview]
Message-ID: <20160712153520.GG613@sigill.intra.peff.net> (raw)
In-Reply-To: <CAPc5daWcb5bfgsxMP0vCrQ7gBdeYBgefzPNHztaaCKzqbCv2aQ@mail.gmail.com>
On Tue, Jul 12, 2016 at 08:25:51AM -0700, Junio C Hamano wrote:
> On Tue, Jul 12, 2016 at 8:16 AM, Jeff King <peff@peff.net> wrote:
> >>
> >> But moving the internal time representation used in various fields
> >> like commit->date to time_t is likely to be a wrong thing to do,
> >> because the first problem with "unsigned long", i.e. "may not be
> >> wide enough", is not limited to "not wide enough to hold time_t".
> >> It also includes "it may not be wide enough to hold time somebody
> >> else recorded in existing objects".
> >
> > But that's a problem no matter what size we choose.
>
> Yes, if somebody's time_t is larger than my intmax_t, the problem
> cannot be solved for me, if that timestamp is too far in the future or
> in the past.
I am less worried about their time_t and more about whatever crap they
write in ascii into their objects. :)
> But that is not the problem I am pointing out. I heard earlier in the
> thread that time_t on one system was 32-bit (was it Linux?) but I think
> they have "long long". Choosing time_t is strictly inferior choice when
> we already know that a platform with not-wide-enough time_t need to
> be supported, and a type that is wider than that is available.
I am not certain that there is a modern system with 32-bit time_t. We
know there are systems with 32-bit unsigned long, and I think that is
what produced the results people saw. I'd expect even 32-bit systems to
use "int64_t" or similar for their time_t these days.
I'm also not convinced that we would be helping much to carry around a
wider gittime_t. Most of the display code ends up touching a system time
function one way or another, so I find it unlikely it would produce much
better output.
It would help for simple cases like commit->date where we really do just
parse it into a number and never do more with it. But...
> I was envisioning that we would have typedef <sometime> gittime_t
> with conversion helpers between it and time_t that allow us to do some
> range checks while at it.
I guess I am just willing to trust that time_t is basically that. And if
your platform has a grossly undersized time_t, then too bad, we clamp
everything it can't hold to 2038 or whatever, and hopefully your
terrible platform dies out or gets a clue sometime in the next 20 years.
-Peff
next prev parent reply other threads:[~2016-07-12 15:35 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-11 20:13 [ANNOUNCE] Git v2.9.1 Junio C Hamano
2016-07-11 21:35 ` Andreas Schwab
2016-07-11 23:54 ` Jeff King
2016-07-12 0:40 ` Anders Kaseorg
2016-07-12 14:06 ` Jeff King
2016-07-12 0:56 ` Eric Wong
2016-07-12 1:15 ` Jeff King
2016-07-12 1:59 ` Junio C Hamano
2016-07-12 3:57 ` Jeff King
2016-07-12 15:55 ` Junio C Hamano
2016-07-12 7:30 ` Johannes Schindelin
2016-07-12 7:39 ` Jeff King
2016-07-12 11:25 ` Johannes Schindelin
2016-07-12 14:04 ` Jeff King
2016-07-13 11:35 ` Johannes Schindelin
2016-07-13 16:03 ` Junio C Hamano
2016-07-13 19:10 ` Johannes Schindelin
2016-07-13 19:41 ` Junio C Hamano
2016-07-14 7:50 ` Johannes Schindelin
2016-07-12 18:12 ` Junio C Hamano
2016-07-13 1:53 ` Junio C Hamano
2016-07-13 2:01 ` Jeff King
2016-07-13 16:05 ` Junio C Hamano
2016-07-13 18:52 ` Johannes Schindelin
2016-07-13 19:07 ` Junio C Hamano
2016-07-14 7:45 ` Johannes Schindelin
2016-07-14 8:01 ` Andreas Schwab
2016-07-14 8:15 ` Jeff King
2016-07-14 16:06 ` Johannes Schindelin
2016-07-12 7:40 ` Andreas Schwab
2016-07-12 10:57 ` Johannes Schindelin
2016-07-12 13:00 ` Andreas Schwab
2016-07-12 13:22 ` Johannes Schindelin
2016-07-12 13:31 ` Andreas Schwab
2016-07-12 13:46 ` Jeff King
2016-07-12 18:38 ` Duy Nguyen
2016-07-13 11:29 ` Johannes Schindelin
2016-07-13 11:25 ` Johannes Schindelin
2016-07-12 14:34 ` Junio C Hamano
2016-07-12 15:16 ` Jeff King
2016-07-12 15:25 ` Junio C Hamano
2016-07-12 15:35 ` Jeff King [this message]
2016-07-12 15:41 ` Junio C Hamano
2016-07-12 16:09 ` Jeff King
2016-07-12 16:25 ` Junio C Hamano
2016-07-13 14:00 ` Johannes Schindelin
2016-07-13 16:10 ` Junio C Hamano
2016-07-13 18:53 ` Johannes Schindelin
2016-07-12 18:15 ` Andreas Schwab
2016-07-13 20:43 ` Junio C Hamano
2016-07-14 7:38 ` Lars Schneider
2016-07-16 5:50 ` Duy Nguyen
2016-07-14 7:58 ` 32-bit Travis, was " Johannes Schindelin
2016-07-14 9:12 ` Mike Hommey
2016-07-14 10:58 ` Johannes Schindelin
2016-07-15 1:59 ` Mike Hommey
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