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 | ||
| 16 | class APIForgotPasswordController extends Controller | ||
| 17 | { | ||
| 18 | /** | ||
| 19 | * Send a reset link to the given user. | ||
| 20 | * | ||
| 21 | * @param Request $request | ||
| 22 | * @return JsonResponse | ||
| 23 | */ | ||
| 24 | View Code Duplication | public function sendResetLinkEmail(Request $request) | |
| 39 | |||
| 40 | /** | ||
| 41 | * Send a reset link to the given users. | ||
| 42 | * | ||
| 43 | * @param Request $request | ||
| 44 | * @return JsonResponse | ||
| 45 | */ | ||
| 46 | View Code Duplication | public function massiveSendResetLinkEmail(Request $request) | |
| 64 | } | ||
| 65 | 
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: