Fix DateInterval::createFromDateString return type for PHP 8.3+

[xelaris]

On PHP 8.3 and newer DateInterval::createFromDateString() throws DateMalformedIntervalStringException on failure instead of returning false (see php/php-src#10366). Psalm still reports PossiblyFalseReference when calling a method on the return value of createFromDateString, even when targeting PHP 8.3 and newer.

See also https://www.php.net/manual/en/dateinterval.createfromdatestring.php#refsect1-dateinterval.createfromdatestring-changelog

The return type change was considered in CallMap_84_delta.php, but I think it should be in CallMap_83_delta.php.

The CallMap lookup seems to be skipped for Psalm's own stubs. I added a Php83.phpstub that overrides the createFromDateString definition in stubs/CoreGenericClasses.phpstub with return type DateInterval.

psalm/stubs/CoreGenericClasses.phpstub

Lines 624 to 631 in ca15124

	/**
	* Sets up a DateInterval from the relative parts of the string
	* @return DateInterval|false Returns a new {@link https://www.php.net/manual/en/class.dateinterval.php DateInterval}
	* instance on success, or <b>FALSE</b> on failure.
	* @link https://php.net/manual/en/dateinterval.createfromdatestring.php
	* @psalm-ignore-falsable-return
	*/
	public static function createFromDateString(string $datetime = ''): DateInterval|false {}

There are two new test cases in CoreStubsTest. One is confirming the return type is still DateInterval|false for PHP 8.2 and the other one is confirming it's DateInterval on PHP 8.3.

[zoltan-schwarz]

I'm on php8.4, but it is still inferring false as possible return type. Tried direct cli argument --php-version= also defining in the config file, it's there in the composer.json. I even defined a local stub. Still I resolved false. Am I missing something.