.. _php-noreferenceforstaticproperty:

.. _no-reference-for-static-property:

No Reference For Static Property
++++++++++++++++++++++++++++++++

  `Static <https://www.php.net/manual/en/language.oop5.static.php>`_ 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 <https://www.php.net/manual/en/language.oop5.static.php>`_ properties are shared between inheriting classes, unless the `static <https://www.php.net/manual/en/language.oop5.static.php>`_ property is explicitly overridden in a child class. However, due to an implementation artifact it was possible to separate the `static <https://www.php.net/manual/en/language.oop5.static.php>`_ properties by assigning a reference. This loophole has been fixed.

.. code-block:: php
   
   <?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 <https://github.com/php/php-src/blob/3b6e1ee4ee05678b5d717cd926a35ffdc1335929/UPGRADING#L66-L81>`_.


Specs
_____

+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Short name       | Php/NoReferenceForStaticProperty                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Rulesets         | :ref:`All <ruleset-All>`, :ref:`Changed Behavior <ruleset-Changed-Behavior>`, :ref:`CompatibilityPHP53 <ruleset-CompatibilityPHP53>`, :ref:`CompatibilityPHP54 <ruleset-CompatibilityPHP54>`, :ref:`CompatibilityPHP55 <ruleset-CompatibilityPHP55>`, :ref:`CompatibilityPHP56 <ruleset-CompatibilityPHP56>`, :ref:`CompatibilityPHP70 <ruleset-CompatibilityPHP70>`, :ref:`CompatibilityPHP71 <ruleset-CompatibilityPHP71>`, :ref:`CompatibilityPHP72 <ruleset-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 <https://php-changed-behaviors.readthedocs.io/en/latest/behavior/.html>`__                                                                                                                                                                                                                                                                                                                                                                                           |
+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Precision        | Very high                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Available in     | `Entreprise Edition <https://www.exakat.io/entreprise-edition>`_, `Exakat Cloud <https://www.exakat.io/exakat-cloud/>`_                                                                                                                                                                                                                                                                                                                                                              |
+------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+