On 6/9/20 11:53 AM, Michael H Deckers wrote:
In all the cases where I could check the exact time of day of a switch to time zone time, this turned out to be the case -- except, of course, for Dublin on 1916-10-01 where British law said that the time had to jump from 03:00:00 to 02:25:21.1.
There are other such cases in tzdb. For example, the 1911-03-11 transition in Paris is from 00:01 Paris Mean Time to 23:51:39 GMT the previous day. If the comments are right this transition came from Ciro Disceopolo but we don't have exact citations.
I guess I just wanted to say that the default jump produced by zic is not necessarily a good guess of what really has happened (except possibly for Britain).
Absolutely. It's a tension between making it clear in the source code that the time (or in some cases even date) is not known, versus coming up with the most-likely guess. There's no single right answer here.