On Feb 19, 2019, at 11:00 AM, Stephen Colebourne <scolebourne@joda.org> wrote:
On Tue, 19 Feb 2019 at 16:35, Paul Eggert <eggert@cs.ucla.edu> wrote:
setting "Vietnamese" data or systems to an "Asia/Bangkok" tzdb identifier would, to some degree, effectively tie that data to Thai legislation.
Vietnamese systems looking to future dates should be set to Asia/Ho_Chi_Minh, shouldn't they?
Currently, they agree, so it doesn't matter whether, for current dates/times, you use Asia/Bangkok or Asia/Ho_Chi_Minh. In the past, they didn't agree, so, to correctly convert dates/times between 1970 and reunification in 1975, you should use Asia/Bangkok for North Vietnam and Asia/Ho_Chi_Minh for South Vietnam. If Vietnam changes in such a fashion so that future dates will not properly be handled by Asia/Bangkok, they won't properly be handled by the current Asia/Ho_Chi_Minh. In that case, we should probably bring Asia/Hanoi into asia from backzone, and update both Asia/Hanoi and Asia/Ho_Chi_Minh to the new rules, so that locations in what was North Vietnam would use Asia/Hanoi and locations in what was South Vietnam would use Asia/Ho_Chi_Minh.