On 9/21/21 1:49 PM, Tom Lane wrote:
while the data may be there, it's no longer possible to extract it in a way that matches prior results.
It is possible to extract it, if you use the patches I mentioned earlier today <https://mm.icann.org/pipermail/tz/2021-September/030456.html>. Admittedly this is effectively something of a fork and I don't favor this approach, but it is possible.
Consumers who value data stability are out in the cold.
If you value data stability, then the current tzdb repository is better than going to a one-Zone-per-country rule, because the latter would cause more data churn than the former does, due to all the Links that would turned into Zones that would differ before 1970.
I just re-ran my experiment comparing the zoneinfo tree generated by 2021a to what I get from current tzdb git. I get the same set of zone files, except for a couple of expected recent changes such as Pacific/Kanton. However:
* without backzone, there are 65 zone files/links that change contents compared to 2021a
Yes. This mostly affects only timestamps before 1970.
* with backzone, there are 95 zone files/links that change content.
That also sounds about right. That's the extra data churn I mentioned above. In other words, if the goal is data stability, you're better off with the current development repository, than with a fork that goes to a one-Zone-per-country rule.
It looks like 25 of the changes are shared between the two trees and so probably represent actual recent updates, rather than effects of the May rearrangements.
I am not sure how you're counting, but only 11 files represent updates other than the May rearrangements. Here's the list: America/Barbados America/Guyana Atlantic/Azores Atlantic/Madeira Europe/Lisbon Pacific/Apia Pacific/Enderbury Pacific/Niue Pacific/Rarotonga Pacific/Tongatapu Portugal I got this list by using the abovementioned patches.
I think there is going to be a fork
Any fork won't save you from the before-1970 changes you're concerned about, unless you give up on equity goals.