[tz] OpenJDK/CLDR/ICU/Joda issues with Ireland change

Clive D.W. Feather clive at davros.org
Thu Jan 25 17:47:39 UTC 2018

Guy Harris said:
> and therefore its "raw GMT offset" was -7 hours prior to 02:00 local time, 2003-10-26, and -6 hours after that point, and given that getRawOffset() does *not* take a time as an argument.

Again, this happened in the UK when we went on to and then off of British
Standard Time. And it's the origin of the Irish Problem.

> In ICU4C, useDaylightTime() "works" because it returns an "observes DST" indication for "the current (Gregorian) calendar year", although that won't work if a region chooses to start or stop observing DST at some time other than midnight, as, in the year when they switch, it "observes DST" for part of the year and doesn't "observe DST" for the rest of the year.

Do you mean "midnight of New Year" by that? UK/Ireland had that as well.

> So "standard time" in Ireland doesn't mean the same thing it means in most other countries, and, presumably, a properly internationali{s,z}ed program would, in the middle of summer, report that Ireland is on Irish Standard Time or something such as that.


Clive D.W. Feather          | If you lie to the compiler,
Email: clive at davros.org     | it will get its revenge.
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