RFR: 8340073: Support "%z" time zone abbreviation format in TZ files [v2]

[Justin Lu]

On Fri, 13 Sep 2024 18:39:42 GMT, Naoto Sato <naoto at openjdk.org> wrote:

>> Yet another preparation for upgrading the time zone data to 2024b, which introduced a new abbreviation format "%z". The update includes:
>> ...
>>       The main source files' time zone abbreviations now use %z,
>>       supported by zic since release 2015f and used in vanguard form
>>       since release 2022b. For example, America/Sao_Paulo now contains
>>       the zone continuation line "-3:00 Brazil %z", which is less error
>>       prone than the old "-3:00 Brazil -03/-02". This does not change
>>       the represented data: the generated TZif files are unchanged.
>>       Rearguard form still avoids %z, to support obsolescent parsers.
>> ...
>> 
>> Also fixed the logic to retrieve the linked tz name that is chaining.
>
> Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Do not add all links

IIUC we treat the %z _FORMAT_ the same as the numeric offset _FORMAT_, that is we rely on the _STDOFF_ to calculate the GMT format during runtime.
The changes in `convertGMTName(String f)` seem to accomplish that.

src/java.base/share/classes/sun/util/cldr/CLDRTimeZoneNameProviderImpl.java line 270:

> 268:         ResourceBundle fd = lr.getJavaTimeFormatData();
> 269:         var zi = ZoneInfoFile.getZoneInfo(id);
> 270:         if (zi == null) {

This is an added fallback, and is not related to the "%z" logic right?

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Marked as reviewed by jlu (Committer).

PR Review: https://git.openjdk.org/jdk/pull/20979#pullrequestreview-2304414315
PR Review Comment: https://git.openjdk.org/jdk/pull/20979#discussion_r1759703352