PHP-CS-Fixer/doc/rules/class_notation/final_class.rst

====================
Rule ``final_class``
====================

All classes must be final, except abstract ones and Doctrine entities.

Description
-----------

No exception and no configuration are intentional. Beside Doctrine entities and
of course abstract classes, there is no single reason not to declare all classes
final. If you want to subclass a class, mark the parent class as abstract and
create two child classes, one empty if necessary: you'll gain much more fine
grained type-hinting. If you need to mock a standalone class, create an
interface, or maybe it's a value-object that shouldn't be mocked at all. If you
need to extend a standalone class, create an interface and use the Composite
pattern. If these rules are too strict for you, you can use
``FinalInternalClassFixer`` instead.

Warning
-------

Using this rule is risky
~~~~~~~~~~~~~~~~~~~~~~~~

Risky when subclassing non-abstract classes.

Examples
--------

Example #1
~~~~~~~~~~

.. code-block:: diff

   --- Original
   +++ New
    <?php
   -class MyApp {}
   +final class MyApp {}
References
----------

- Fixer class: `PhpCsFixer\\Fixer\\ClassNotation\\FinalClassFixer <./../../../src/Fixer/ClassNotation/FinalClassFixer.php>`_
- Test class: `PhpCsFixer\\Tests\\Fixer\\ClassNotation\\FinalClassFixerTest <./../../../tests/Fixer/ClassNotation/FinalClassFixerTest.php>`_

The test class defines officially supported behaviour. Each test case is a part of our backward compatibility promise.