ZEND_ARG_VARIADIC_TYPE_INFO(0, str, IS_STRING, 0) does not enforce strings

[divinity76]

Description

When doing

function str_starts_with(string $haystack, string ...$needle): bool {}
(...)
ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_str_starts_with, 0, 1, _IS_BOOL, 0)
	ZEND_ARG_TYPE_INFO(0, haystack, IS_STRING, 0)
	ZEND_ARG_VARIADIC_TYPE_INFO(0, needle, IS_STRING, 0)
ZEND_END_ARG_INFO()

You would think that the string type would be enforced with strict_types=1

but it doesn't! If you do

function str_starts_with(string $haystack, string ...$needle): bool {}
(...)
ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_str_starts_with, 0, 1, _IS_BOOL, 0)
	ZEND_ARG_TYPE_INFO(0, haystack, IS_STRING, 0)
	ZEND_ARG_VARIADIC_TYPE_INFO(0, needle, IS_STRING, 0)
ZEND_END_ARG_INFO()
(...)
    zval *needles;
    size_t num_needles;
    ZEND_PARSE_PARAMETERS_START(2, -1)
        Z_PARAM_STR(haystack)
        Z_PARAM_VARIADIC('+', needles, num_needles)
    ZEND_PARSE_PARAMETERS_END();
    for (size_t i = 0; i < num_needles; ++i) {
        Z_STR(needles[i]); // << segfault on int
    }

and 1 of the needles is an int, you get a segfault!

PHP Version

current git master, 3399235bec275516f6b87714087526d36d6f6976

Operating System

Ubuntu 24.04

[nielsdos]

Arginfo never enforces anything. It's just metadata. The enforcement of the argument types happens via the ZPP functions or macros.
In this case you have to do it yourself.