This is basically what I was about when asking for the "scope" of tzdb, and might end up in a similar discussion concerning timezone ids just like the Wikipedia's inclusionism/exclusionism debate.

Standpoints:

a) (Exclusionist) Timezone ids should be kept at a minimum level required to model tz rules appropriately
b) (Inclusionist) There should be at least one timezone id for each ISO 3166-1 TLC
...and as the "Hanoi" case would not be covered by (b) the even extended inclusionist approach would rather be something like:
c) (Inclusionist+) There should be at least one timezone id for each "timezone" (in the sense of tzdb's consistent-since-1970 definition) for each ISO 3166-1 TLC

However it looks like there is no real solution to this, as either choice has its subtleties. So sticking to the status quo might be the best to do for now.

While I think I understand the perspective of people who are arguing to focus on core tzdb maintenance, I'd however encourage tzdb "users" (which I guess are also represented on this list) to speak up regarding challenges they observe.

I think such discussion might be worthwhile 1) to raise sensitivity for tzdb usage challenges in this community and 2) to better understand pain points in the usage of time zones / time zone identifiers in general.

For instance, has anybody ever seen an approach such as advised in the note suggested by Paul [1], or are we actually all sticking to just storing  tzdb identifiers?

Thanks and best,
Hans-Joerg

Timezone boundaries are not part of the stable interface.
For example, even though the <samp>Asia/Bangkok</samp> timezone
currently includes Chang Mai, Hanoi, and Phnom Penh, this is not part
of the stable interface and the timezone can split at any time.
If a calendar application records a future event in some location other
than Bangkok by putting "<samp>Asia/Bangkok</samp>" in the event's record,
the application should be robust in the presence of timezone splits
between now and the future time.

I strongly oppose this patch. At least one zone per ISO 3166-1 is a
vital part of this project and an entirely sensible rule. It is what
users expect the project to provide.

TZDB identifiers are used incredibly widely, and are seen on many
public-facing systems. I understand that is not seen as desirable by
some here, but it is the truth. When a country splits, it is usually
for painful reasons. The idea that the half of the country should be
forced to use the old identifier simply isn't tenable.

Stephen


On Tue, 19 Feb 2019 at 23:17, Paul Eggert <eggert@cs.ucla.edu> wrote:

On 2/19/19 2:31 PM, Tim Parenti wrote:

So, since it's pretty clear that the "There should typically be at
least one name for each ISO 3166-1 officially assigned two-letter code
for an inhabited country or territory" guideline has been, if not
abandoned entirely, at least significantly de-prioritized, perhaps
theory.html needs an update indicating that, yes, this /used/ to be
considered more important, but is not any longer (perhaps going a bit
into the rationale), and that we don't intend to create new zones
anymore if that's the only justification.

Sounds good to me; proposed patch attached.

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