Max Nikulin <maniku...@gmail.com> writes: > https://debbugs.gnu.org/cgi/bugreport.cgi?bug=54764#30 > Re: bug#54764: encode-time: make DST and TIMEZONE fields of the list > Thu, 14 Apr 2022 15:46:58 -0700 >> If you want to keep the TZDB identifier for advice about how to >> interpret dates relative to a timestamp, that's fine. But you should >> keep the UT offset in addition to the TZDB identifier, if you want your >> app to be fully accurate and useful. For example, you should store >> "1950-07-01 00:00:00 +0000 Europe/Lisbon" for a timestamp generated by >> TZDB release 2021a, so that when you interpret the timestamp in release >> 2021b you'll have an idea of what you're dealing with. > > So keeping redundant information may be crucial to get warnings that > some timestamps need to be reviewed.
My takeaway from here is that automatically generated timestamps for past events should better contain redundant information: "1950-07-01 00:00:00 +0000 Europe/Lisbon" +0000 is what matters for time calculation while Europe/Lisbon indicates the actual timezone being implied. Then, if there is an event of TZ database change, Org might compare +0000 vs. Europe/Lisbon and display warning if there is discrepancy. For us, it means that we might potentially reserve <1950-07-01 00:00:00+0000@Europe/Lisbon> as a valid timestamp format. Warning is optional feature we might implement in future. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at <https://orgmode.org/>. Support Org development at <https://liberapay.com/org-mode>, or support my work at <https://liberapay.com/yantar92>
