[release/6.0] Fix TimeZoneInfo.HasIanaId when using Local Time Zone

[tarekgh]

Fixes #58326

Backport of #58392 to release/6.0

/cc @tarekgh

Customer Impact

Without this fix, users of TimeZoneInfo.HasIanaId can get wrong values when using TimeZoneInfo.Local.

We have exposed the new property TimeZoneInfo.HasIanaId in .NET 6.0. This property tells if the Time Zone object is created with IANA Id. This property returns the correct results except when using TimeZoneInfo.Local. The reason is when we initialize TimeZoneInfo.Local property we clone the object before returning it, but we missed cloning HasIanaId property inside the returned object. The fix is to ensure HasIanaId is initialized correctly in TimeZoneInfo.Local.

Testing

I tested this on Windows and Linux. Also, I have run the whole regression tests with the fix without any problem. I added more tests to cover the test gap for the functionality we are fixing here.

Risk

Is low. The fix is scoped to the HasIanaId property only which is a newly exposed property in .NET 6.0. The change is well tested and added more tests too.

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Issue Details

---

Fixes #58326

Backport of #58392 to release/6.0

/cc @tarekgh

Customer Impact

Without this fix, users of TimeZoneInfo.HasIanaId can get wrong values when using TimeZoneInfo.Local.

We have exposed the new property TimeZoneInfo.HasIanaId in .NET 6.0. This property tells if the Time Zone object is created with IANA Id. This property returns the correct results except when using TimeZoneInfo.Local. The reason is when we initialize TimeZoneInfo.Local property we clone the object before returning it, but we missed cloning HasIanaId property inside the returned object. The fix is to ensure HasIanaId is initialized correctly in TimeZoneInfo.Local.

Testing

I tested this on Windows and Linux. Also, I have run the whole regression tests with the fix without any problem. I added more tests to cover the test gap for the functionality we are fixing here.

Risk

Is low. The fix is scoped to the HasIanaId property only which is a newly exposed property in .NET 6.0. The change is well tested and added more tests too.

Author:	tarekgh
Assignees:	-
Labels:	area-System.Globalization
Milestone:	-

[tarekgh]

CC @danmoseley @ericstj

[danmoseley]

Approved for release/6.0. Clear defect in a new API, reported by partner, localized fix.

[tarekgh]

CC @eerhardt

[tarekgh]

CC @@roji

[tarekgh]

@danmoseley could you please merge this one? Thanks!