[tz] [english 100%] Re: [english 100%] Re: OpenJDK/CLDR/ICU/Joda issues with Irelandchange

[Paul Eggert]

Stephen Colebourne wrote:
> On 26 January 2018 at 07:46, Paul Eggert <eggert at cs.ucla.edu> wrote:
>> Meno Hochschild wrote:
>>>
>>> I have adjusted my tzdb-compiler (Time4J) such that it looks if all rule
>>> lines referencing the same name (here: Eire) contain any negative dst
>>> offsets. If yes then let's assume summer time for SAVE=0 and winter time for
>>> SAVE < 0. So I can still work with old unchanged CLDR-entries for getting
>>> "Irish Standard Time" in summer.
>>
>> This sounds like a good idea regardless of whether we make changes to zic
>> input. Couldn't OpenJDK do the same?
> 
> Such an approach is merely adding an even more subtle API to TZDB, one
> where a mixture of positive and negative SAVE values would cause
> chaos.

What sort of chaos, exactly? Meno Hochschild is not reporting any chaos.

> Meno's approach with an extra column actually tackles the heart of the
> problem by providing a stable key that can be used to link the two
> projects.

Such a key could be given in a separate data file, which could be used by zi 
parsers that do not support negative DST offsets, or that have other specialized 
requirements. That would be less disruptive than changing zic input format for 
purposes unrelated to zic.

For this particular issue I'm hoping that we can use an even less-disruptive 
approach, such as the one proposed here:

https://mm.icann.org/pipermail/tz/2018-January/026002.html

which should avoid the need for an extra column or an extra file.