[tz] What data should TZDB offer?

[Clive D.W. Feather]

Tom Lane via tz said:
> One other issue that I think deserves more attention than it has
> gotten lately is that tzdb has become a de facto standard and users
> rely on its stability.  I would like to see some sort of principle
> adopted that minimizes changes in historical data.
[...]
> and also
> the changes a few years ago that removed "made up" zone abbreviations.
> Whatever the justification for those abbreviations originally, some
> people had come to depend on them, and little was to be gained by
> removing them.

But I'd like another principle to be "truth". We should not be making up
data - that goes both for lying about LMT offsets and lying about the
abbreviations people use.

Remember that the basic principle was "what's used on the ground".

> The idea of having at least one zone per ISO-3166-1 country does
> seem like a good one, though.  Aside from possibly deflecting
> politically-based complaints,

And adding other ones.

> this seems basically like future
> proofing: even if two countries have shared clocks since 1970,
> they could diverge at any time.

So can a country and a dependent territory. Or even a non-dependent one: to
pick a fanciful example, as part of the upcoming EU changes, Italy could
decide to stick to UTC+2 but France to UTC+1, then Corsica decide to go to
UTC+2.

> Being prepared with an appropriate
> zone name should minimize the pain to users.

Why not wait until it's needed? We're likely to get more notice than we get
for some countries' Ramadan changes.

-- 
Clive D.W. Feather          | If you lie to the compiler,
Email: clive at davros.org     | it will get its revenge.
Web: http://www.davros.org  |   - Henry Spencer
Mobile: +44 7973 377646