Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php |
||
| 10 | class SettingsStorage extends Component implements SettingsStorageInterface |
||
| 11 | { |
||
| 12 | /** |
||
| 13 | * @var Connection |
||
| 14 | */ |
||
| 15 | private $connection; |
||
| 16 | |||
| 17 | public function init() |
||
| 21 | |||
| 22 | /** |
||
| 23 | * @inheritdoc |
||
| 24 | */ |
||
| 25 | View Code Duplication | public function setGlobal($key, $value) |
|
| 33 | |||
| 34 | /** |
||
| 35 | * @inheritdoc |
||
| 36 | */ |
||
| 37 | View Code Duplication | public function setBounded($key, $value) |
|
| 45 | |||
| 46 | /** |
||
| 47 | * @inheritdoc |
||
| 48 | */ |
||
| 49 | View Code Duplication | public function getGlobal($key) |
|
| 58 | |||
| 59 | /** |
||
| 60 | * @inheritdoc |
||
| 61 | */ |
||
| 62 | View Code Duplication | public function getBounded($key) |
|
| 71 | |||
| 72 | /** |
||
| 73 | * Performs request to the API |
||
| 74 | * |
||
| 75 | * @param string $key |
||
| 76 | * @param array $value |
||
| 77 | * @return array |
||
| 78 | */ |
||
| 79 | private function perform($key, $value) |
||
| 87 | |||
| 88 | private function decodeResponse($response) |
||
| 93 | } |
||
| 94 |
Let’s assume that you have a directory layout like this:
. |-- OtherDir | |-- Bar.php | `-- Foo.php `-- SomeDir `-- Foo.phpand let’s assume the following content of
Bar.php:If both files
OtherDir/Foo.phpandSomeDir/Foo.phpare loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.phpHowever, as
OtherDir/Foo.phpdoes not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: