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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| 24 | class Builder extends Command |
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| 25 | { |
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| 26 | /** |
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| 27 | * {@inheritdoc} |
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| 28 | */ |
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| 29 | protected $signature = 'app:build {name=application : The build name} {--with-dev : Whether the dev dependencies should be included}'; |
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| 30 | |||
| 31 | /** |
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| 32 | * {@inheritdoc} |
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| 33 | */ |
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| 34 | protected $description = 'Perform an application build'; |
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| 35 | |||
| 36 | /** |
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| 37 | * Contains the default app structure. |
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| 38 | * |
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| 39 | * @var string[] |
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| 40 | */ |
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| 41 | protected $structure = [ |
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| 42 | 'app'.DIRECTORY_SEPARATOR, |
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| 43 | 'bootstrap'.DIRECTORY_SEPARATOR, |
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| 44 | 'vendor'.DIRECTORY_SEPARATOR, |
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| 45 | 'config'.DIRECTORY_SEPARATOR, |
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| 46 | 'composer.json', |
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| 47 | 'builder-stub', |
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| 48 | '.env', |
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| 49 | ]; |
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| 50 | |||
| 51 | /** |
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| 52 | * Holds the stub name. |
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| 53 | * |
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| 54 | * @var string |
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| 55 | */ |
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| 56 | protected $stub = 'builder-stub'; |
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| 57 | |||
| 58 | /** |
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| 59 | * Holds the configuration on is original state. |
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| 60 | * |
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| 61 | * @var string |
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| 62 | */ |
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| 63 | protected static $config; |
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| 64 | |||
| 65 | /** |
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| 66 | * {@inheritdoc} |
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| 67 | */ |
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| 68 | 1 | public function handle(): void |
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| 81 | |||
| 82 | /** |
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| 83 | * Builds the application into a single file. |
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| 84 | * |
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| 85 | * @param string $name The file name. |
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| 86 | * |
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| 87 | * @return $this |
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| 88 | */ |
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| 89 | 1 | protected function build(string $name): Builder |
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| 107 | |||
| 108 | /** |
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| 109 | * @param string $name |
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| 110 | * |
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| 111 | * @return $this |
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| 112 | */ |
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| 113 | 1 | protected function compile(string $name): Builder |
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| 145 | |||
| 146 | /** |
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| 147 | * Gets a new instance of the compiler. |
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| 148 | * |
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| 149 | * @param string $name |
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| 150 | * |
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| 151 | * @return \Phar |
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| 152 | */ |
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| 153 | 1 | protected function getCompiler(string $name): \Phar |
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| 165 | |||
| 166 | /** |
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| 167 | * @return $this |
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| 168 | */ |
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| 169 | 1 | protected function makeBuildsFolder(): Builder |
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| 177 | |||
| 178 | /** |
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| 179 | * Sets the executable mode on the single application file. |
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| 180 | * |
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| 181 | * @param string $name |
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| 182 | * |
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| 183 | * @return $this |
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| 184 | */ |
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| 185 | 1 | protected function setPermissions($name): Builder |
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| 191 | |||
| 192 | /** |
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| 193 | * @return $this |
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| 194 | */ |
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| 195 | 1 | protected function prepare(): Builder |
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| 224 | |||
| 225 | /** |
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| 226 | * @return $this |
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| 227 | */ |
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| 228 | 1 | protected function clear(): Builder |
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| 244 | |||
| 245 | /** |
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| 246 | * Makes sure that the `clear` is performed even |
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| 247 | * if the command fails. |
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| 248 | * |
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| 249 | * @return void |
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| 250 | */ |
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| 251 | 18 | public function __destruct() |
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| 258 | } |
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| 259 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: