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:
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18 | class ReflectionObject |
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19 | { |
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20 | private $object; |
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21 | private $properties; |
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22 | private $injectionStrategy; |
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23 | private $extractionStrategy; |
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25 | 13 | View Code Duplication | public function __construct( |
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47 | /** |
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48 | * Add a property that will be injected |
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49 | * |
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50 | * @param string $name |
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51 | * @param mixed $value |
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52 | * |
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53 | * @return self |
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54 | */ |
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55 | 4 | public function withProperty(string $name, $value) |
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64 | |||
65 | /** |
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66 | * Add a set of properties that need to be injected |
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67 | * |
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68 | * @param array<string, mixed> $properties |
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69 | * |
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70 | * @return self |
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71 | */ |
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72 | 1 | View Code Duplication | public function withProperties(array $properties): self |
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88 | /** |
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89 | * Return the collection of properties that will be injected in the object |
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90 | * |
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91 | * @return MapInterface<string, mixed> |
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92 | */ |
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93 | 2 | public function properties(): MapInterface |
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98 | /** |
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99 | * Return the list of injection strategies used |
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100 | * |
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101 | * @return InjectionStrategyInterface |
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102 | */ |
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103 | 1 | public function injectionStrategy(): InjectionStrategyInterface |
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107 | |||
108 | /** |
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109 | * Return the list of extraction strategies used |
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110 | * |
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111 | * @return ExtractionStrategyInterface |
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112 | */ |
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113 | 1 | public function extractionStrategy(): ExtractionStrategyInterface |
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118 | /** |
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119 | * Return the object with the list of properties set on it |
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120 | * |
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121 | * @return object |
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122 | */ |
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123 | public function build() |
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132 | /** |
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133 | * Extract the given list of properties |
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134 | * |
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135 | * @param string[] $properties |
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136 | * |
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137 | * @return MapInterface<string, mixed> |
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138 | */ |
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139 | 2 | public function extract(array $properties): MapInterface |
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153 | /** |
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154 | * Inject the given key/value pair into the object |
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155 | * |
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156 | * @param string $key |
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157 | * @param mixed $value |
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158 | * |
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159 | * @return void |
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160 | */ |
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161 | 5 | private function inject(string $key, $value): void |
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166 | /** |
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167 | * Extract the given property out of the object |
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168 | * |
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169 | * @param string $property |
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170 | * |
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171 | * @return mixed |
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172 | */ |
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173 | 2 | private function extractProperty(string $property) |
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177 | } |
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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: