[tz] Single source of truth for timezone data

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Fri Dec 9 19:58:07 UTC 2022

On 2022-12-08 13:50, Paul Eggert via tz wrote:
> On 2022-12-08 05:24, Almaz Mingaleev wrote:
>>>> new timezone abbreviation "XYT", downstream distros like Ubuntu can
>>>> immediately ship the new P without waiting for i18n updates. P will

>> It is not a problem if a distro ships it, it is a problem if this new
>> stuff leaks to the external world.

> Sorry, I'm not following. When Ubuntu ships a new tzdata package then surely 
> that has "leaked" to the outside world?

>> It would be naive to expect from a user base of a service to have
>> up-to-date time zone data even after a month after TZDB release.

> In the past I've gotten my Ubuntu systems updated within 24 hours of a tzdata 
> release, simply by applying patches as usual from Ubuntu. But as Benjamin 
> indicates, this is not happening with 2022g. I just now checked for updates and 
> I'm still stuck on 2022f. So from my point of view, Ubuntu is slow in this case 
> - instead of taking less than a day, it's taking more than a week.

>> being consistently wrong about _new_ changes is better
>> than having different answers within the platform.

> As a Ubuntu user, I'd prefer tzdata to be up-to-date even though ICU is 
> out-of-date, over having both tzdata and ICU out-of-date. Of course Ubuntu 
> differs from Android in that most apps use tzdata not ICU. Still, I'm a bit 
> curious what end-user-visible problems would occur on Android and/or Ubuntu if 
> tzdata leads ICU slightly. I know you've seen problems, but were they end-user 
> problems or just test-case problems? On Ubuntu various other copies of tzdata 
> (e.g., Python's) can be slightly out of date too, but this doesn't seem to be 
> much of an issue.

>> It is not translations that we are waiting for, but changes like [1 
>> <https://github.com/unicode-org/icu/pull/2261/files>]. Recent time zone
>> changes were short notice ones and ICU team (thanks Yoshito and others!) 
>> did these changes very quickly.

> Thanks, I didn't know that.
> Here's a timeline I see for the latest Mexico change:
> * 2022-11-28 17:00 UTC - news article published announcing the change (which is 
> not official yet, I think) 
> <http://puentelibre.mx/noticia/ciudad_juarez_cambio_horario_noviembre_2022/>
> * 2022-11-29 03:55:31 UTC - tz mailing list notified 
> <https://mm.icann.org/pipermail/tz/2022-November/032365.html>
> * 2022-11-29 17:42:29 UTC (14 hours after notification) - tzdb 2022g announced 
> <https://mm.icann.org/pipermail/tz-announce/2022-November/000076.html>
> * 2022-11-29 18:23:41 UTC (less than an hour after tzdb 2022g announcement) 
> tzdata 2022g-r0 released for Alpine Linux 
> <https://pkgs.alpinelinux.org/package/edge/main/x86/tzdata>
> * 2022-11-30 07:06 UTC (7 hours after tzdb 2022g announcement) - tzdata 2022g-1 
> released for Arch Linux <https://archlinux.org/packages/core/x86_64/tzdata/>
> * 2022-12-01 03:08:08 UTC (33 hours after tzdb 2022g announcement) - 
> abovementioned ICU patch committed
> * 2022-12-01 12:38:06 UTC (9 hours after ICU patch committed) - Ubuntu patch 
> committed <https://launchpad.net/ubuntu/+source/tzdata/2022g-0ubuntu0.22.10.1>
> * 2022-12-05 (4 days after ICU patch committed) - Red Hat Enterprise Linux fix 
> available to users <https://access.redhat.com/errata/RHBA-2022:8785>
> * 2022-12-07 (6 days after ICU patch committed) - Android patch committed 
> <https://android.googlesource.com/platform/system/timezone/+/ea3e0ece71974c1df741b1b0d7789682d6d40dea>
> * now (a week after ICU patch committed) - my Ubuntu workstation is still not 
> updated.
> We should be able to do better than this; that is, be more like Alpine or Arch 
> Linux, or at least more like RHEL (though I see that Fedora still hasn't 
> released 2022g...). Though ICU is part of the problem (as is tzdb itself :-), 
> most of the delay seems to be occurring even after ICU patches are applied.

Launchpad shows Ubuntu 22.10 Proposed kinetic-proposed/main tzdata 2022g, also 
jammy- and focal-proposed, released Dec 1 when the maintainer started this thread.

You could add the -proposed source to apt sources, and/or set apt preferences to 
only use it for tzdata, as the -proposed source seems to be first to get ICU 
updates in tzdata package release yyyyX-0ubuntu0.MM.mm.1; -updates and -security 

Take care. Thanks, Brian Inglis			Calgary, Alberta, Canada

La perfection est atteinte			Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter	not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer	but when there is no more to cut
			-- Antoine de Saint-Exupéry

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