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@xxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html