array_filter ignores strict_types

[divinity76]

Description

The following code:

<?php
declare(strict_types=1);

$arr = ["1"];
$filtered = array_filter($arr, function (int $i) {
    var_dump(["func_get_args" => func_get_args()]);
    return true;
});
var_dump($arr);

Resulted in this output:

array(1) {
  ["func_get_args"]=>
  array(1) {
    [0]=>
    int(1)
  }
}
array(1) {
  [0]=>
  string(1) "1"
}

But I expected this output instead:

Fatal error: Uncaught TypeError: {closure}(): Argument #1 ($i) must be of type int, string given in /in/Gf4Pq:5
Stack trace:
#0 [internal function]: {closure}('1')
#1 /in/Gf4Pq(5): array_filter(Array, Object(Closure))
#2 {main}
  thrown in /in/Gf4Pq on line 5

Process exited with code 255.

PHP Version

PHP 8.2.9

Operating System

No response

[KapitanOczywisty]

https://www.php.net/manual/en/language.types.declarations.php#language.types.declarations.strict

Warning Function calls from within internal functions will not be affected by the strict_types declaration.

RFC will be required to change that.

[SakiTakamachi]

I thought it was a bug, so I looked closely at the contents of executor_globals.current_execute_data->prev_execute_data and did trial and error.

It was clearly written in the documentation, but I had overlooked it.
Thank you.

[divinity76]

behaves as documented then I guess.. closing bug report.

[drealecs]

You can add another wrapper for the desired effect:

<?php
declare(strict_types=1);

$arr = ["1"];
$filtered = array_filter($arr, fn(...$_) => (function (int $i) {
    var_dump(["func_get_args" => func_get_args()]);
    return true;
})(...$_));
var_dump($arr);

This will throw an error, as the caller is in the current file, that respects the directive:

Fatal error: Uncaught TypeError: {closure}(): Argument #1 ($i) must be of type int, string given, called in /in/kk8m8 on line 8 and defined in /in/kk8m8:5
Stack trace:
#0 /in/kk8m8(8): {closure}('1')
#1 [internal function]: {closure}('1')
#2 /in/kk8m8(5): array_filter(Array, Object(Closure))
#3 {main}
  thrown in /in/kk8m8 on line 5