1.2.1019. Readonly Property Changed By Cloning

Readonly properties may be changed when cloning. This may happen in the __clone magic method.

In that method, a new object is being created. It is acting like a constructor, and may tweak some of the values of the original object, before assigning them to the new object.

<?php

class x {
     public readonly int $p;

     function __construct($p) {
             $this->p = $p;
     }

     function __clone() {
             // This is possible in a clone, and only once
             $this->p = $this->p + 1;

             // This second call is not possible, as the property was set just above
             $this->p = $this->p + 2;
     }
}

$a = new x(1);
print_r(clone $a);

?>

1.2.1019.1. Specs

Short name	Php/ReadonlyPropertyChangedByCloning
Rulesets	All, Changed Behavior, CompatibilityPHP53, CompatibilityPHP54, CompatibilityPHP55, CompatibilityPHP56, CompatibilityPHP70, CompatibilityPHP71, CompatibilityPHP72, CompatibilityPHP73, CompatibilityPHP74, CompatibilityPHP80, CompatibilityPHP81, CompatibilityPHP82
Exakat since	2.5.3
PHP Version	With PHP 8.3 and more recent
Severity	Minor
Time To Fix	Quick (30 mins)
Precision	High
Available in	Entreprise Edition, Exakat Cloud