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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10 | View Code Duplication | class Worlds |
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11 | { |
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12 | use ImmutableTrait, SerializableTrait; |
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13 | |||
14 | /** |
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15 | * @var int |
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16 | */ |
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17 | private $online; |
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18 | |||
19 | /** |
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20 | * @var array |
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21 | */ |
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22 | private $worlds; |
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23 | |||
24 | /** |
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25 | * Worlds constructor. |
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26 | * @param int $online |
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27 | * @param array $worlds |
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28 | * @throws \Igorsgm\TibiaDataApi\Exceptions\ImmutableException |
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29 | */ |
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30 | public function __construct(int $online, Collection $worlds) |
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38 | /** |
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39 | * @return int |
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40 | */ |
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41 | public function getOnline(): int |
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45 | |||
46 | /** |
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47 | * @return World[] |
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48 | */ |
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49 | public function getWorlds(): Collection |
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53 | } |
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54 |
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: