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

[Paul Eggert]

On 6/7/21 1:05 AM, Derick Rethans wrote:

> Although IMO it is sad to see that some tzids don't
> have pre-1970 data, I don't think you can call it "fair" to then
> remove/restrict/hide away this data for tzids which have this data.

The patch doesn't remove or hide or restrict data. It merely changes the 
category that some data are in. That being said, there is a "fairness" 
question related to the category choice, and I'll discuss that below.
>  From what I remember, the policy/guideline has always just been "don't
> split up zones for only pre-1970 data"

Although "don't split up zones for only pre-1970 data" is certainly part 
of the guidelines, it's not the whole thing. We have merged many zones 
in the past, and these merges were following the guidelines.

> Who was actively asking

This "fairness" question didn't come from a direct request by an end 
user to recategorize existing data. It came indirectly from a user 
request to add a zone for Kosovo, a request that devolved into a heated 
argument that other countries in similar situations have zones so 
Kosovo should have one too. Of course I could have responded that Kosovo 
isn't a "real" country because its ISO 3166 status is X but my 
experience is that such responses can raise hackles even further, and 
that these discussions are better served by appealing directly to 
timekeeping concerns.

Given all the discussion in this thread I don't expect everyone to 
appreciate or agree with my experience, and to some extent I'm trying to 
answer your question rather than argue for the patch, as it looks like 
we'll be better off supporting both the keep-the-patch and the 
undo-the-patch sides of this disagreement.

> If current users don't care about pre-1970 data, then can already invoke
> zic with "zic -r @0" as is documented in zic(8).

Yes, and better support for something along those lines has long been on 
my to-do list ("zic -r at 0" is not enough because it results in 
duplicates). But that's a separate issue. I don't think anyone in the 
current thread has argued for removing all the pre-1970 data.