Loose in_array(string, array, false) on array with mix of string and objects will __toString() those objects ONLY when the first array entry is an object

[phoenixz]

Description

The following code:

<?php
<?php
class Test {
    public function __toString(): string
    {
        die('fail!' . PHP_EOL);
    }
}

$a = [
    'string' => 'test', //  // <=== First position is a string
    'object' => new Test()
];

print_r(in_array('test', $a)); This displays "1", correctly.
echo PHP_EOL;
print_r($a); // This displays the array, correctly, all works as expected

$a = [
    'object' => new Test(), // <=== object is now on first position
    'string' => 'test',
];

print_r(in_array('test', $a)); // Script dies here with "fail!" because in_array() executed Test::__toString()
print_r($a);

Resulted in this output:

1
Array
(
    [string] => test
    [object] => Test Object
        (
        )

)
fail!

But I expected this output instead:

1
Array
(
    [object] => Test Object
        (
        )

    [string] => test
)
1
Array
(
    [object] => Test Object
        (
        )

    [string] => test
)

PHP Version

PHP 8.3.6 (cli) (built: Mar 19 2025 10:08:38) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.3.6, Copyright (c) Zend Technologies
    with Zend OPcache v8.3.6, Copyright (c), by Zend Technologies

Operating System

Ubuntu 24.04.2 LTS

[pospjan]

@phoenixz It's not about the object being (or not being) on the first place, but that the string you are looking for was already found (in_array stops checking other items as it can already return true).

If you modify your first array like this:

$a = [
    'string' => 'test',
    'object' => new Test(),
    'string2' => 'test2', 
];

print_r(in_array('test2', $a)); 

It fails.

[iluuu1994]

Indeed. As explained, nothing surprising is going on here. Loose in_array() comparison does string coercion, and it does so element by element. If your __toString() exists the script, there's nothing we can do about that.