[tz] zoneinfo generating issues

[Guy Harris]

On Mar 6, 2021, at 8:44 AM, Ian Abbott via tz <tz at iana.org> wrote:

> I've just realized that it is normal (as per the zic man page, I think) for the "right" (a.k.a. "leap") zone files to be truncated at the expiry time of the leapseconds file (although the files installed by Debian zic seem to continue beyond the expiry time). I must admit I wasn't expecting that. I thought the output would continue as though there would be no changes to the leap seconds in the future.

After all, we don't truncate the files at the date/time when they're generated, given that we have no guarantee that there will be no changes in the future to the offset from UTC, or the DST rules, for a given tzdb region....