Hooks scoping: accessing the backing value of a property from a method called from a hook on that property must throw an Error, but infinite loop instead.

[BooleanType]

Description

The following code:

<?php
class Person {
    public string $phone {
        set {
        	$this->phone = $this->sanitizePhone($value);
        }
    }
 
    private function sanitizePhone(string $value): string {
    	$this->phone = 15;
        $value = ltrim($value, '+');
        $value = ltrim($value, '1');
 
        if (!preg_match('/\d\d\d\-\d\d\d\-\d\d\d\d/', $value)) {
            throw new \InvalidArgumentException();
        }
        return $value;
    }
}

$p = new Person;
$p->phone = '+1333-555-1234';

Resulted in this output (an infinite loop:):

Fatal error: Uncaught Error: Maximum call stack size of 8339456 bytes (zend.max_allowed_stack_size - zend.reserved_stack_size) reached. Infinite recursion? in /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php:4 Stack trace: #0 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(11): Person->$phone::set(15) #1 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(5): Person->sanitizePhone('15') #2 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(11): Person->$phone::set('15') #3 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(5): Person->sanitizePhone('15') #4 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(11): Person->$phone::set('15') #5 /var/www/47ff65bc-ae0d-4698-be01-b9ccf6d20740.php(5): Person->sanitizePhone('15')...

But I expected triggering an error, as said in documentation, instead:

If a hook calls a method that in turn tries to read or write from the property again, that would normally result in an infinite loop. To prevent that, accessing the backing value of a property from a method called from a hook on that property will throw an Error. That is somewhat different than the existing behavior of __get and __set, where such sub-called methods would bypass the magic methods. However, as valid use cases for such circular logic are difficult to identify and there is added risk of confusion with dynamic properties, we have elected to simply block that access entirely.

PHP Version

PHP 8.4.5

Operating System

No response

[iluuu1994]

Hi @BooleanType. Check https://wiki.php.net/rfc/hook_improvements, this part of the RFC was revised.

[BooleanType]

Ahh, ok, didn't notice that. Thanks!