> You never move events around in TAI (the unambiguous storage format) just as you don't go manually flipping bits in an SQLite database.
You actually do. From the point of view of future scheduled events, a event scheduled for 13h00 in a specific timezone is still "13h00 in a specific timezone" even when crazy people on that timezone suddenly declare a new Daylight savings time to start before the event happens. All future "timestamps" are prone to move due to such shenanigans. And you need to keep your timezone DB as updated as possible to update thing as soon as possible, if you don't want users with wrong times on their future events.
If you're not doing something like full rfc9557 https://datatracker.ietf.org/doc/html/rfc9557 "Internet Extended Date/Time Format (IXDTF)" [iso 8601 local time + as-of-now known timezone offset + IANA timezone] as "timestamps" you're probably truncating important information that will bite you back later if you're doing a calendar/scheduler.
It's a good point. I responded to the adjacent comment.
After glancing at that RFC I'm unclear about the purpose of the UTC offset. Is it simply an error check to catch the case of a datetime library with outdated timezone information? Otherwise it seems like the library will have all the historical information on hand so it shouldn't have any use for it.
You actually do. From the point of view of future scheduled events, a event scheduled for 13h00 in a specific timezone is still "13h00 in a specific timezone" even when crazy people on that timezone suddenly declare a new Daylight savings time to start before the event happens. All future "timestamps" are prone to move due to such shenanigans. And you need to keep your timezone DB as updated as possible to update thing as soon as possible, if you don't want users with wrong times on their future events.
If you're not doing something like full rfc9557 https://datatracker.ietf.org/doc/html/rfc9557 "Internet Extended Date/Time Format (IXDTF)" [iso 8601 local time + as-of-now known timezone offset + IANA timezone] as "timestamps" you're probably truncating important information that will bite you back later if you're doing a calendar/scheduler.