Compatibility with old ICU TZ data

[Yiivgeny]

Problem still in December 2017. Letest CentOS 7, but libicu still same old version and updating still so hard.

Copied from #5128 (comment) (2 year ago)

At first, method formatDateTimeValue is dirty, because use two timezonedb for opposite operation. Time-to-object (with php tzdb), then object-to-string (with icu tzdb)

$DT = new \DateTime;
var_dump($DT->format('c')); //2015-12-17T17:05:02+03:00
var_dump(\Yii::$app->getFormatter()->asDatetime($DT)); //17 дек. 2015 г., 18:05:02

Assume, it's server software problem, but input value already contain TZ info, why not use it for cleanly behavior?

At second, updating timezonedb so hard on some systems, e.g. CentOS 6.x (with all updates and enabled popular update repos) now contain old libicu (Version: 50.1.2 Release Date: 2012-12-17). Updating (http://habrahabr.ru/post/241447/) is not trivial and stable.

I suggest, pass tz-argument for instantiate IntlDateFormatter as offset string (getted from \DateTime object). Result:

• Narrow updates to only php-related tzdata (more friendly framework installing)
• For not-updated environments behavior more cleanly (same result for internal and intl conversions)
• Full BC, in my oppinion.

I can create PR for it.

[samdark]

Would be good.

[schmunk42]

Related:

• Failing tests for DateValidator with ICU tzdata 2017c #15140
• Test-suite fails with ICU 57.1 #13750
• Build image in dockerized tests with BUILD_ARG #15559