Date: Thu, 30 May 2019 11:54:35 +0100 From: Stephen Colebourne <scolebourne@joda.org> Message-ID: <CACzrW9CXTRW_G07E2Y-b2Q4+Ew5jt8LcFSrzR-YSg0gT-0SCTw@mail.gmail.com> | Finally I'll note that *both* views of the data are sensible and reasonable: | - offset-focus: base/standard time in winter, advanced/daylight time | in summer (Java's choice and tzdb's old choice) tzdb never made such a choice - it simply didn't have any data that happened to have the most common (standard) time advanced ahead of the less common offset. What are you planning to do when some part of the US (say Illinois, or something else on Central time) decides to set their zone backwards by an hour for a month in the middle of winter - perhaps the winter olympics come to Denver or something, and they decide that being in the same timezone for that period has more economic and social wins than being an hour off the event times. Certainly that might be unlikely, but it certainly is not impossible, and you're not likely to get much more than a year's warning if it were to happen (at best). Wouldn't planning for this kind of thing now be much more rational than just sticking your heads in the sand with a "we didn't consider that and it is too late now" attitude. If the old APIs need to be deprecated, and a whole new set invented, then so be it - do that - the old ones can be supported, as best they can be given they are based upon false assumptions, for a long time, but averything should be encouraged to convert to something rational, with no in-built assumptions about what is possible or rational wrt local time. | - legal-focus: follow government law as to the meaning of | standard/daylight (tzdb's new choice) First, standard time is the time that applies *now* - whenever now is. If it has a name, distinct from the name that applies to the time at some other time of the year, that's fine (but almost irrelevant to anything). | Most Java libraries aren't going to change because doing so would | impact compatibility in APIs.The real problem here is how tricky it is | to reverse engineer the old data from the new data. I suspect that the real problem is that the current APIs are simply inadequate to describe real world time behaviour. Any assumptions made, anywhere, about almost anything, will almost guarantee that. kre