1.2.827. No Reference For Static Property

Static properties used to behave independently when set to a reference value. This was fixed in PHP 7.3.

According to the PHP 7.3 changelog :

In PHP, static properties are shared between inheriting classes, unless the static property is explicitly overridden in a child class. However, due to an implementation artifact it was possible to separate the static properties by assigning a reference. This loophole has been fixed.

<?php

        class Test {
            public static $x = 0;
        }
        class Test2 extends Test { }

        Test2::$x = &$x;
        $x = 1;

        var_dump(Test::$x, Test2::$x);
        // Previously: int(0), int(1)
        // Now: int(1), int(1)

?>

See also PHP 7.3 UPGRADE NOTES.

1.2.827.1. Specs

Short name	Php/NoReferenceForStaticProperty
Rulesets	All, Changed Behavior, CompatibilityPHP53, CompatibilityPHP54, CompatibilityPHP55, CompatibilityPHP56, CompatibilityPHP70, CompatibilityPHP71, CompatibilityPHP72
Exakat since	1.4.9
PHP Version	With PHP 7.3 and older
Severity	Major
Time To Fix	Slow (1 hour)
Changed Behavior	PHP 7.3 - More
Precision	Very high
Available in	Entreprise Edition, Exakat Cloud