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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14 | class TableApi extends Table |
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15 | { |
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16 | private $alterTable = false; |
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17 | |||
18 | /** |
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19 | * Constructor. |
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20 | * |
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21 | * @param string $table Table name. |
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22 | * @param Schema $schema |
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23 | * @param Manipulation $manipulation |
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24 | * @param array $actions |
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25 | */ |
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26 | public function __construct($name, Schema $schema = null, Manipulation $manipulation, &$actions) |
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32 | |||
33 | /** |
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34 | * @param string $method A method name. |
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35 | * @param array $params Parameters. |
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36 | * |
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37 | * @return TableApi Self. |
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38 | */ |
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39 | public function __call($method, $params) |
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53 | |||
54 | /** |
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55 | * Drop a column. |
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56 | * |
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57 | * @param string $name Column name. |
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58 | * |
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59 | * @return TableApi Self. |
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60 | */ |
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61 | public function dropColumn($name) |
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72 | |||
73 | /** |
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74 | * Add a foreign key. |
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75 | * |
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76 | * @param string $referenceTable Referenced table name. |
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77 | * @param string $referenceColumns Columns of referenced table. |
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78 | * @param array $options Optional options. |
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79 | * |
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80 | * @return TableApi Self. |
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81 | */ |
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82 | public function addForeignKey($referenceTable, $referenceColumns, array $options = []) |
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106 | |||
107 | /** |
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108 | * Drop a foreign key. |
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109 | * |
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110 | * @param string $referenceTable Referenced table name. |
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111 | * @param string $referenceColumns Columns of referenced table. |
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112 | * @param array $options Optional options. |
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113 | * |
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114 | * @return TableApi Self. |
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115 | */ |
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116 | public function dropForeignKey($referenceTable, $referenceColumns, array $options = []) |
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130 | |||
131 | /** |
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132 | * Add a unique constraint. |
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133 | * |
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134 | * @param array $columns Unique columns. |
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135 | * |
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136 | * @return TableApi Self. |
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137 | */ |
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138 | View Code Duplication | public function addUnique($columns) |
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148 | |||
149 | /** |
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150 | * Drop a unique constraint. |
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151 | * |
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152 | * @param array $columns Unique columns. |
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153 | * |
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154 | * @return TableApi Self. |
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155 | */ |
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156 | View Code Duplication | public function dropUnique($columns) |
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166 | |||
167 | /** |
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168 | * Add a index on columns. |
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169 | * |
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170 | * @param array $columns Index columns. |
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171 | * |
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172 | * @return TableApi Self. |
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173 | */ |
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174 | View Code Duplication | public function addIndex($columns) |
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184 | |||
185 | /** |
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186 | * Drop a index on columns. |
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187 | * |
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188 | * @param array $columns Index columns. |
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189 | * |
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190 | * @return TableApi Self. |
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191 | */ |
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192 | View Code Duplication | public function dropIndex($columns) |
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202 | } |
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203 |
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: