Tickets :: Comment on [#13947] Calendar breaks on DST start date

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Comment	>> It's a bug with the DateJS library then. > > (sorry if I'm flooding this with comments; let me know and I'll be quiet) > > It is hard to call that a bug, because there is no "right" way to do > it. Just adding 1 to the month day number would be wrong, because > "Date" is actually a "DateTime", so the time has to be taken into > account too. > > If you think about it, 00:00 - 00:59 October 18th 2015 does not exist > in my timezone because at 23:59:59.99 on the 17th you set your clock > to 01:00:00.00 (and each DST-using timezone has such gap). > > So adding 1 day to "Oct 17th 00:00" cannot result in "Oct 18th 00:00" > as that is an invalid datetime in this timezone. IMO, the "best" > result would be that the .add or .next methods returned an "invalid > date", and left it to the calling program to decide what to do. > Instead, each implementation seems to "decide" what to return (in > some Android cases, it's 31/12/1969 00:00!). > > So when we are just interested in the Date and not Time, it is much > safer to set the time to something far from 00:00 (some timezones > switch at 01:00) before doing date math.
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