Chile is delaying the DST by one week for 2022

[Ioanna Alifieraki]

New timezone data, with the following timezones impacted:
- Chile will spring forward on 2022-09-11, not 2022-09-04 (America/Santiago)
- Iran no longer observes DST (Asia/Tehran)

Verification is done with 'zdump'. The first timezone that gets changed in the updated package is dumped with 'zdump -v $region/$timezone_that_changed' (this needs to be greped for in /usr/share/zoneinfo/). [For example: 'zdump -v Asia/Gaza'.] This is compared to the same output after the updated package got installed. If those are different the verification is considered done.

[Test Case for all releases]
1) zdump -v America/Santiago | grep 'Sep.*2022'
  -> should indicate Sep 11, not Sep 4
2) zdump -v Asia/Tehran | tail
  -> last dates should be in 2022, not in 2499

[Test Case for releases >= 20.04 LTS]

For releases with ICU timezone data verification is done using the following with dates before and after the change:
1) sudo apt-get install python3-icu
2) Run the following python script:

from datetime import datetime
from icu import ICUtzinfo, TimeZone
tz = ICUtzinfo(TimeZone.createTimeZone("America/Santiago"))
always_before = datetime(2022, 9, 1)
now_before = datetime(2022, 9, 8)
always_after = datetime(2022, 9, 12)
assert(tz.utcoffset(always_before) == tz.utcoffset(now_before))
assert(tz.utcoffset(now_before) != tz.utcoffset(always_after))

The assertions would crash on 2022a.

[Test Case for releases <= 20.04 LTS]

Additionally, an upstream update of tzdata removed the 'old' SystemV timezones, so we should ensure that they are kept in Ubuntu 20.04 LTS and earlier releases. Subsequently, these should be checked for using the following:
diff <(zdump -v America/Phoenix | cut -d' ' -f2-) <(zdump -v SystemV/MST7 | cut -d' ' -f2-)

Nothing should be returned by the above command.

[Original report]
Chile is delaying the start of Daylight Saving Time (DST) by one week this year [1],[2].

DST timezone in Chile will start on midnight of September 11th; and will end on April 1st, 2023.

Debian's 2022c-1 and 2022b-1 versions of tzdata contain the fix for this.

Upstream commit :
https://github.com/eggert/tz/commit/711b46f8fc4e8a3d5caf7d4820562d6cdfe9d769

We need to fix this in all or releases back to Xenial.

[1] https://www.interior.gob.cl/noticias/2022/08/09/comunicado-el-proximo-sabado-10-de-septiembre-los-relojes-se-deben-adelantar-una-hora/
[2] https://www.timeanddate.com/news/time/chile-dst-delay-2022.html#:~:text=Chile%20is%20delaying%20the%20start,financial%20district%20in%20Chile%27s%20capital.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

This bug was fixed in the package tzdata - 2022c-1ubuntu1

---------------
tzdata (2022c-1ubuntu1) kinetic; urgency=medium

  * Merge with Debian unstable (LP: #1987642). Remaining changes:
    - Ship ICU timezone data files which are utilized by php and update them to
      2022b as 2022c isn't available

tzdata (2022c-1) unstable; urgency=medium

  * New upstream version, no changes to the timezones.

tzdata (2022b-1) unstable; urgency=medium

  [ Aurelien Jarno ]
  * New upstream version:
    - Chile's 2022 DST start is delayed from September 4 to September 11.
    - Iran plans to stop observing DST permanently, after it falls back
      on 2022-09-21.
  * debian/tzdata.config: convert Europe/Kiev into Europe/Kyiv.
  * debian/tzdata.templates, debian/po/*: update templates and translation
    following the above change.
  * Bump Standards-Version to 4.6.1 (no changes).

tzdata (2022a-1) unstable; urgency=high

  [ Aurelien Jarno ]
  * New upstream version:
    - Palestine will spring forward on 2022-03-27, not -03-26.
  * Set urgency to high as the Palestine DST change is in 4 days.
  * debian/tzdata.config: do not try to get a value from debconf if it hasn't
    been seen yet. Closes: #999465.
  * Update English debconf translation.

  [ Johannes Schauer Marin Rodrigues ]
  * Add support for support DPKG_ROOT. Closes: #1007756.

 -- Simon Chopin <email address hidden> Mon, 29 Aug 2022 10:14:49 +0200