Description

The following code:

<?php
class MyString {
    function __toString() {
        return "2";
    }
}

$a = new BCMath\Number("1");
$b = new MyString();
var_dump($a + $b, $b);

Resulted in this output:

object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(1) "3"
  ["scale"]=>
  int(0)
}

string(1) "2"

But I expected this output instead:

object(BcMath\Number)#2 (2) {
  ["value"]=>
  string(1) "3"
  ["scale"]=>
  int(0)
}
object(MyString)#2 (0) {
}

Note that this even happens in strict typing mode, where it may not even be expected that the addition succeeds.

Anyhow, the problem is that zend_parse_arg_str_or_long_slow() converts the passed arg.

Also note that GMP also uses ZPP functionality, but catches any such type conversion, even in coercive typing mode.

PHP Version

PHP 8.4

Operating System

any