BCMath\Number operators may typecast operand

[cmb69]

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

[cmb69]

Confirmed: https://3v4l.org/6g9B3/rfc#vgit.master

Somewhat different issue, but also related to bcmath_number_parse_num():

<?php declare(strict_types=0);
var_dump(new BCMath\Number("1") + null);

does not throw a deprecation warning, as it is supposed to, since the RFC states:

Calculations with the operator behave as if the corresponding method's optional arguments were not specified.

And for strict typing, the operation succeeds, but the method fails.

[iluuu1994]

/cc @SakiTakamachi