Add DatePeriod's __serialize and __unserialize methods (#8464)

Fixed reference count issue with zend_string

Fixed cloning DateInterval

Add support for serialising all DateInterval objects

Fixed cloning DateInterval

Rename have_special_relative to from_string, fix serialisation constraint, and reorder fields

Show the 'have_special_relative' property in var_dumps, and disallow serialization if set

Fixed memory leak with manual calls to DateInterval::__unserialize

Add DateInterval's __serialize and __unserialize methods

Remove fake properties from DateInterval

Fixed memory leak with unserialize was called multiple times and an abbreviation was stored

Add DateTimeZone's __serialize and __unserialize methods

Add DateTime/DateTimeImmutable's __serialize and __unserialize methods

Merge branch 'PHP-8.1'

Merge branch 'PHP-8.0' into PHP-8.1

Use the new RETURN_THROWS() instead of just returning NULL

Merge branch 'PHP-8.1'

Merge branch 'PHP-8.0' into PHP-8.1

Return early when the timezone info is NULL.

The guess_timezone function does throw an error, but throwing an error doesn't
immediate make the PHP_FUNCTION return.

This check is

Return early when the timezone info is NULL.

The guess_timezone function does throw an error, but throwing an error doesn't
immediate make the PHP_FUNCTION return.

This check is really only necessary for distributions that patch PHP's timelib
to use system tzdata, but not correct enough to account for their
implementation to guarantee to return a timezone.

show more ...

Merge branch 'PHP-8.1'

Merge branch 'PHP-8.0' into PHP-8.1

Refactor code to avoid duplication

style/readability updates

GH-7979: iterator advances when checking if valid

Merge branch 'PHP-8.1'