[tz] timezone Verschlimmbesserung

Paul Eggert eggert at cs.ucla.edu
Tue Oct 5 17:10:33 UTC 2021


On 10/4/21 12:59 PM, Steffen Nurpmeso via tz wrote:

> (It would surely be doable to use tooling to automatically unite
> all zones which are identical post-1970, maybe give that an
> auto-generated name, and make all actual TZIDs which point to that
> data links automatically.)

I wrote such a tool to generate the May proposal, except that I didn't 
invent new names as I thought that would entail unnecessary complexity 
and confusion. It was kind of a hack, though, and not worth publishing.


> What really bugs me with the current post-1970-matters rule is
> that the "ZFLAGS='-r @0'" option is neither default nor
> prominently documented.

Making it the default would be a big lift, as people have expressed 
concern about churn in pre-1970 data. In hindsight perhaps we should 
have omitted pre-1970 data from the start (it sure would have saved me a 
lot of ill-spent time ...) but the backward-compatibility concerns do 
exist even if they're perhaps overblown.


> Also that tzselect(8) gives the name of the actually really used
> zone instead of the name that was used

Could you explain more about this issue? I don't see how a "name that 
was used" is involved here. When a user starts up tzselect, there is no 
name yet. tzselect is supposed to let you choose a name de novo.

Perhaps you could show a sample tzselect session and explain where it 
goes wrong?


As for the importance of astrological use of the tzdb main entries - 
tzdb has never been remotely adequate for pre-1970 timestamps, and I see 
no movement on the horizon to fix this. I have asked an astrologer or 
two for help on this topic with no results, not that I expected any; any 
effort in this area would have to be huge to get decent coverage.

Here's one way to think about it. After about 40 years of volunteer 
work, we have reasonable coverage for casting horoscopes for people aged 
50 or less. On current trends we can solve the problem of casting 
horoscopes for living persons, simply by doing nothing for the next 40 
years or so. Perhaps that's not ideal for astrologers, but it's pretty 
good bang for the buck.


More information about the tz mailing list