On Tue, Jun 1, 2010 at 11:40 PM, Guido van Rossum <guido@python.org> wrote:
Also note that there will be no validation possible for future datetimes (and for past dates it would require an up-to-date leap second database).
It's even worse than that :(. Complete validation would also require timezone knowledge, because leap seconds happen at the same instant the world over: e.g., the leap second that occurred at 23:59:60 UTC on 31st December 2008 occurred at 19:29:60 local time in Caracas. So for naive datetime objects validation is going to be difficult. Given that timezone offsets can be an arbitrary number of minutes, the only reasonable options as far as I can see would be either *always* to accept seconds in the range 0-60, or *always* restrict the range to 0-59, as now. (Well, you could only accept seconds=60 for timestamps within 24 hours of midnight on Jun 30 or Dec 31st, but that's fairly horrible. :-) I'm still not convinced that incorrectly accepting some invalid UTC times is worse than incorrectly rejecting some (rare) valid UTC times, but I'll let it drop for now. -- Mark