[jdk11u-dev] RFR: 8288377: [REDO] DST not applying properly with zone id offset set with TZ env variable [v3]

[Gaurav Chaudhari]

On Tue, 13 Sep 2022 17:21:35 GMT, Gaurav Chaudhari <duke at openjdk.org> wrote:

>> Backport changes from JDK-8288377
>
> Gaurav Chaudhari has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Merge branch 'customtz-dst-fix-backport-3c32564' of github.com:Deigue/jdk11u-dev into customtz-dst-fix-backport-3c32564
>  - Fixed CustomTzIDCheckDST compile error due to incorrect func signature.

Backport Request jdk-11u
Requesting this fix to be backported in order to address https://bugs.openjdk.org/browse/JDK-8288377 , which fixes the incorrect timezone displayed in DST period, when a custom TZ code is used. The risk is minimal as the code change is only a small piece of logic in how the offset between GMT and local time is calculated and returned. [(offset fix)](https://github.com/openjdk/jdk11u-dev/pull/1328/files#diff-806fc08210f7476f46a4df89d03c1e3a53ca528812ce0f4a7a2dd58cbaa36dcdR884) In addition, the repeat definition of the function for macOS has been consolidated, while keeping the macOS specific logic when it is needed. Tier 1 testing is passing on macOS and Linux.

Assuming that this backport approval request is step 6 of [how to contribute a fix](https://wiki.openjdk.org/display/JDKUpdates/How+to+contribute+a+fix) , I wanted to add that a small tweak was made to the original backport on jdk11u (this PR **only**, jdk-17 and jdk-19 are clean backports) , and thus as per step 5 I will be needing a code review on this PR as it won't be labeled as clean. The only new [change](https://github.com/openjdk/jdk11u-dev/pull/1328/files#diff-1ef896deae588b4f1c6c07a1e87789288ff996a555257e7abb2509bb6a0088e3R45) was modifying the arguments to the `createJavaProcessBuilder` function as its function signature differs within this repo to accept String params instead of a List of Strings.

Please let me know if I need to also comment a request like this on both the other PRs as well, since they are going to be more or less quite similar.

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PR: https://git.openjdk.org/jdk11u-dev/pull/1328