New sniff: change dirname( __FILE__ ) to __DIR__

[jrfnl]

Sniff basics	-
Fixable for PHP:	5.3+
Sniff type:	Modernize
Fixer type:	Safe

Short description

PHP 5.3 introduced the magic constant __DIR__ which is equivalent to dirname( __FILE__ ) and more efficient to use - function call vs native PHP (magic) constant -.

Related PHPCompatibility sniff(s):

• NewKeywords

PHP manual references:

• 5.3.0 | Added DIR and NAMESPACE constants

  This is equivalent to dirname(FILE).

  http://php.net/manual/en/language.constants.predefined.php

Example code:

Detect the following code pattern(s):

dirname( __FILE__ );

And fix these to:

__DIR__

Notes for implementation of the sniff:

• The sniff would need to take code patterns like the below into account:

  $dir = defined('__DIR__') ? __DIR__ : dirname(__FILE__);

Prior art:

• CS-Fixer: dir_constant