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data: Add 2023d #1085

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merged 1 commit into from Dec 29, 2023
Merged

data: Add 2023d #1085

merged 1 commit into from Dec 29, 2023

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gilmoreorless
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This is a rework of #1084 using a freshly-compiled zic and zdump from the IANA source. There turned out to be two separate bugs at play with the initial data build:

  1. macOS's zdump was previously very old and only handled 32-bit data, which this project's build process could catch and warn about. The latest Sonoma releases have updated to zdump from 2022g which works just enough to look like it's fine.
  2. zic and zdump had bugs that inadvertently dropped some transitions from a small number of zones. This was fixed in 2023d, which is why zones like America/Ciudad_Juarez now have more data without the source files changing. (It only affects transitions after the year 2400, so not a big deal.)
  3. This lead to the combination of zdump@2022g compiling data@2023d on macOS, which look like it worked properly, but was subtly wrong. Zones like America/Godthab dropped any transitions after 2023, which was definitely not correct. Manually compiling zdump from the 2023d source fixed that issue in this PR.

Interestingly, the new (previously-missing) data for America/Ciudad_Juarez also contains some buggy transitions right after the previous data cut-off. There's possibly another bug lurking in tzcode somewhere.


The PR contains the following changes from tzdb (edited to remove details irrelevant to this project):

Release 2023d - 2023-12-21 20:02:24 -0800

  Changes to future timestamps

    Ittoqqortoormiit, Greenland (America/Scoresbysund) joins most of
    the rest of Greenland's timekeeping practice on 2024-03-31, by
    changing its time zone from -01/+00 to -02/-01 at the same moment
    as the spring-forward transition.  Its clocks will therefore not
    spring forward as previously scheduled.  The time zone change
    reverts to its common practice before 1981.

    Fix predictions for DST transitions in Palestine in 2072-2075,
    correcting a typo introduced in 2023a.

  Changes to past and future timestamps

    Vostok, Antarctica changed to +05 on 2023-12-18.  It had been at
    +07 (not +06) for years.  (Thanks to Zakhary V. Akulov.)

    Change data for Casey, Antarctica to agree with timeanddate.com,
    by adding five time zone changes since 2020.  Casey is now at +08
    instead of +11.

  Changes to past tm_isdst flags

    Much of Greenland, represented by America/Nuuk, changed its
    standard time from -03 to -02 on 2023-03-25, not on 2023-10-28.
    This does not affect UTC offsets, only the tm_isdst flag.
    (Thanks to Thomas M. Steenholdt.)

  Changes to code

    zic no longer mishandles data for Palestine after the year 2075.
    Previously, it incorrectly omitted post-2075 transitions that are
    predicted for just before and just after Ramadan.  (Thanks to Ken
    Murchison for debugging help.)

Closes #1083

@gilmoreorless
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I've sent a message to the tzdb mailing list to check about the strange America/Ciudad_Juarez data: https://mm.icann.org/pipermail/tz/2023-December/033392.html

@gilmoreorless gilmoreorless merged commit 585fabf into develop Dec 29, 2023
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@gilmoreorless gilmoreorless deleted the data/2023d branch December 29, 2023 10:47
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