setlocale's 2nd and 3rd argument ignores strict_types

[divinity76]

Description

The following code:

<?php
declare(strict_types=1);
try{
setlocale(LC_ALL, 0,"0"); // 2nd argument is a strict_types violation
}finally{
setlocale(LC_ALL, "0",0); // 3rd argument is a strict_types violation
}

Resulted in this output:

But I expected this output instead:

Uncaught TypeError: setlocale(): Argument #2 ($locales) must be of type string, int given in /in/dqfQT:4
Uncaught TypeError: setlocale(): Argument #3 ($rest) must be of type string, int given in /in/dqfQT:6

PHP Version

PHP8.4.8

Operating System

WSL Ubuntu 24.04

[divinity76]

fwiw it seems the varargs api is currently incapable of checking types at compile time, until the varargs api is upgraded,
i think if(ZEND_ARG_USES_STRICT_TYPES()){TypeError...} is the solution for the vararg strings 🤔

• i am not working on this, i was just looking for a string ...$args example in php-src for another thing. setlocale was the only such function i found, and turns out it doesn't respect strict_types, which is exactly what i was looking for: how to respect strict_types in string ...$args in C. seems the answer is ZEND_ARG_USES_STRICT_TYPES()

[divinity76]

probably related to #18826

[nielsdos]

The second and third argument are handled in the same way (i.e. via variadics), which explains why they are both inconsistent.
An implicit conversion to string happens here:

php-src/ext/standard/string.c

Line 4915 in 7f3a2bc

zend_string *loc_str = zval_try_get_tmp_string(loc_zv, &tmp_loc_str);

To fix this, a manual type check must be added in the for loop here (I think, on first sight):

php-src/ext/standard/string.c

Line 4936 in 7f3a2bc

for (uint32_t i = 0; i < num_args; i++) {