[Bug 2012599] Re: tzdata 2023a/2023b/2023c release - Egypt restoring DST

Wed Mar 29 14:29:56 UTC 2023

** Description changed:

  [ Impact ]

  Recently the Egyptian authorities decided to restore DST. The first
  switch after the change is expected to take place on last Friday of
  April. The upstream tzdata 2023a release already reflects this change.

  The 2023a release contains the following changes:

  * Egypt now uses DST again, from April through October.
  * This year Morocco springs forward April 23, not April 30.
  * Palestine delays the start of DST this year.
  * Much of Greenland still uses DST from 2024 on.

  The 2023c release reverts the changes done in 2023b.

  [ Test Plan ]

  Test cases were added to the autopkgtest to cover the testing:

  * python: test_2023a
  * python: test_2023c
  * python: test_systemv_timezones (for releases <= 20.04 LTS)
  * python-icu: test_2023a (only for kinetic, jammy, focal)

  So the test plan is to check that the autopkgtest succeeds.

  Alternatively the python test_2023a can be run manually:

   * Set system timezone to Egypt (e.g. Africa/Cairo).
   * Set system time to 2023-04-27 23:59.
   * Wait and observe what happens at 2023-04-28 0:00

  [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. This is done by the test_systemv_timezones test case or can be checked manually with the following:
  diff <(zdump -v America/Phoenix | cut -d' ' -f2-) <(zdump -v SystemV/MST7 | cut -d' ' -f2-)

  [ Where problems could occur ]

   * Systems with incorrect timezone set (e.g. located outside of Egypt
  but still using Egyptian time) may observe unexpected time shift.

  [ Other Info ]

  The autopkgtest for chrony is flaky on jammy and kinetic (see bug
  #2002910).

   * More information with sources:
  https://en.wikipedia.org/wiki/Daylight_saving_time_in_Egypt#:~:text=Daylight%20saving%20time%20(DST)%20has,(DST)%20as%20of%202023.

  The SRUs to the stable include the recent changes for generating the
- debconf template and the timezone mappings in convert_timezone().
- Previous SRUs did forget to update them for the changes from upstream.
- All added tests were also backported.
+ debconf template (switching from shell code to Python) and the timezone
+ mappings in convert_timezone(). Previous SRUs did forget to update them
+ for the changes from upstream. All added tests (for testing the debconf
+ template and convert_timezone) were also backported.

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https://bugs.launchpad.net/bugs/2012599

Title:
  tzdata 2023a/2023b/2023c release - Egypt restoring DST

Status in tzdata package in Ubuntu:
  Fix Committed
Status in tzdata source package in Bionic:
  Fix Committed
Status in tzdata source package in Focal:
  Fix Committed
Status in tzdata source package in Jammy:
  Fix Committed
Status in tzdata source package in Kinetic:
  Fix Committed
Status in tzdata source package in Lunar:
  Fix Committed

Bug description:
  [ Impact ]