[tz] Undoing the effect of the new alike-since-1970 patch

David Patte dpatte at relativedata.com
Tue Jun 8 11:15:59 UTC 2021

Nice and clear workable solution, as far as I can see.

On 2021-06-08 04:56, Stephen Colebourne via tz wrote:
> On Sun, 6 Jun 2021 at 19:59, Paul Eggert <eggert at cs.ucla.edu> wrote:
>> If that process is too much trouble for downstream users, we can arrange
>> to generate the alternate source upstream. For example, we could ship a
>> tarball with an altered tzdata.zi file (this is what Tom suggested).
> As noted previously, there are two main groups in the debate - minimal
> and maximal.
> 1) The minimal group believe TZDB should only focus on data after 1970
> and use the minimum set of IDs necessary to achieve that (considering
> the ID name to have no meaning or value pre-1970).
> 2) The maximal group believe TZDB should place greater value on
> pre-1970 data and the name of the ID (considering that governmental
> authorities are an important part of time-keeping).
> It is possible to automatically derive the data for group 1 from the
> data for group 2. The other way around is not possible.
> I'm suggesting that the default data in the repo is for group 2 with a
> way to derive group 1. This could result in two separate downloadable
> tarballs.
> I imagine the tasks would be:
> - take the relevant parts of the `backzone` data and put it back in
> the main files (Canada/Montreal would not be put back for example)
> - add a new `idmerge` file identifying IDs that are the same post-1970
> and which ID should be the one to have its history retained
> - alter the makefile to have a "minimal" option to use the new `idmerge` file
> An alternative approach that avoids the `idmerge` file would be for
> the "minimal" option to simply strip all pre-1970 data
> Stephen

More information about the tz mailing list