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 |
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19 | final class PluginClientFactoryListener implements EventSubscriberInterface |
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20 | { |
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21 | /** |
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22 | * @var CollectorPluginClientFactory |
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23 | */ |
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24 | private $factory; |
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25 | |||
26 | /** |
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27 | * @param CollectorPluginClientFactory $factory |
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28 | */ |
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29 | 5 | public function __construct(CollectorPluginClientFactory $factory) |
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33 | |||
34 | /** |
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35 | * Make sure to profile clients created using PluginClientFactory. |
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36 | * |
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37 | * @param Event $e |
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38 | */ |
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39 | 5 | public function onEvent(Event $e) |
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43 | |||
44 | /** |
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45 | * {@inheritdoc} |
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46 | */ |
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47 | 5 | View Code Duplication | public static function getSubscribedEvents() |
54 | } |
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55 |
Let’s assume that you have a directory layout like this:
and let’s assume the following content of
Bar.php
:If both files
OtherDir/Foo.php
andSomeDir/Foo.php
are 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.php
However, as
OtherDir/Foo.php
does 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: