On 11/17/21 02:03, Stephen Colebourne via tz wrote:
On Tue, 16 Nov 2021 at 18:20, Paul Eggert <eggert@cs.ucla.edu> wrote:
I was thinking that one can look in zone.tab. If the spelling is there it's "preferred" otherwise it's not.
That makes these categories less useful. It involves a downstream consumer processing zone.tab and cross-checking it. It also doesn't handle the case where there is a spelling change for an ID that is not listed in zone.tab.
You're right that it's a bit more work downstream, and that it doesn't handle arbitrary questions about which names are preferred to which other names (for example, it doesn't establish a total order on names). However, it does seem to suffice for the specific problem you mentioned about backwards compatibility (one name per ISO country), and it has the advantage of not burdening the upstream maintenance process with even more political questions.
It is not at all clear why you would want the `primary` category to contain both Asia/Kolkata and Asia/Calcutta.
The idea was that the 'primary' category would be about the timestamps (where Asia/Kolkata and Asia/Calcutta are identical), not about the metadata (where people might disagree about how to spell the city's name). This would help insulate tzdb from political issues. Although we cannot insulate tzdb completely from politics, when it's easy to do so then we should do it.