On 09/04/13 09:24, Stephen Colebourne wrote:
If Scotland has its own time different from England, then one tzdb might name it Edinburgh and the forked tzdb uses Glasgow. That divergence, or non-ubiquity, would be very unhelpful to everyone that needs time-zone data.
Yes, we should try to avoid this. Nothing like that is being proposed, thanks goodness.
For example, the removal of "Castries Mean Time" and "Kingstown Mean Time" will be visible in Joda-Time, and the change to the end of LMT will be visible in Joda-Time and JSR-310.
No historical data are being lost here. "Castries Mean Time" and "Kingstown Mean Time" are artifices of the tz database (I should know, since I invented them) and do not reflect any known historical data. More generally, no doubt regression tests will report changes because of the proposed patch, because that's what regression tests do: they report changes. But ordinary users won't care that time stamps in Aruba on February 12, 1912 from 04:35:47 to 04:40:24 UTC will have a UTC offset that differs by a few minutes. They just won't. We've done this sort of thing before, and it doesn't cause problems. The tz database has often seen updates like this, and it's just not that big a deal.
America/Curacao and America/Aruba have exactly the same time since the year dot apart from the LMT value (they do have the same LMT end date).
The transitions don't have the same UTC end time, though, so merging these two would also cause regression software to report a change. If "no change" is the criterion, then no changes will pass muster.