[tz] Interfaces (was Re: Issues with pre-1970 information in TZDB)

[Stephen Colebourne]

On Thu, 23 Sept 2021 at 07:16, Murray S. Kucherawy via tz <tz at iana.org> wrote:
> On Wed, Sep 22, 2021 at 3:08 PM Stephen Colebourne <scolebourne at joda.org> wrote:
>> The subtlety is in how the data set is consumed. While many downstream
>> projects use the makefile, not all do. A significant portion of
>> downstream users make use of the source files directly, with their own
>> parsers. ie. there is no ability to use a compile-time option. Those
>> parsers are not setup to use backzone even if it were a valid option
>> (Tom Lane has indicated how you can't reverse engineer the 2021a data
>> cleanly from backzone as it is mixed with lots of other historic data
>> that has been similarly abandoned). Even if the parsers were to be
>> updated (and in the case of CLDR's backwards compatibiilty it is not
>> clear that they can), it is not appropriate to have to make the change
>> without a significant notice period.
>
> I had a feeling this was the answer.
>
> I think this warrants a critical question: What is the intended interface to the data?

While it is a good critical question, the reality is that the source
files are used by downstream users. In fact, there are many different
downstream parsers of the source files. It is certainly far too late
to remove access to the source files - they are a de facto interface
to the project. Previous changes to the source files have already been
met with strong resistance.

Stephen