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 |
||
23 | class Builder extends Command |
||
24 | { |
||
25 | /** |
||
26 | * Contains the default app structure. |
||
27 | * |
||
28 | * @var string[] |
||
29 | */ |
||
30 | protected $structure = [ |
||
31 | 'app' . DIRECTORY_SEPARATOR, |
||
32 | 'bootstrap' . DIRECTORY_SEPARATOR, |
||
33 | 'vendor' . DIRECTORY_SEPARATOR, |
||
34 | 'config' . DIRECTORY_SEPARATOR, |
||
35 | 'composer.json', |
||
36 | 'builder-stub', |
||
37 | '.env' |
||
38 | ]; |
||
39 | |||
40 | /** |
||
41 | * Holds the stub name. |
||
42 | * |
||
43 | * @var string |
||
44 | */ |
||
45 | protected $stub = 'builder-stub'; |
||
46 | |||
47 | /** |
||
48 | * {@inheritdoc} |
||
49 | */ |
||
50 | protected $signature = 'app:build {name=application : The build name}'; |
||
51 | |||
52 | /** |
||
53 | * {@inheritdoc} |
||
54 | */ |
||
55 | protected $description = 'Perform an application build'; |
||
56 | |||
57 | /** |
||
58 | * Holds the configuration on is original state. |
||
59 | * |
||
60 | * @var string |
||
61 | */ |
||
62 | protected static $config; |
||
63 | |||
64 | /** |
||
65 | * {@inheritdoc} |
||
66 | */ |
||
67 | 1 | public function handle(): void |
|
80 | |||
81 | /** |
||
82 | * Builds the application into a single file. |
||
83 | * |
||
84 | * @param string $name The file name. |
||
85 | * |
||
86 | * @return $this |
||
87 | */ |
||
88 | 1 | protected function build(string $name): Builder |
|
106 | |||
107 | /** |
||
108 | * @param string $name |
||
109 | * |
||
110 | * @return $this |
||
111 | */ |
||
112 | 1 | protected function compile(string $name): Builder |
|
141 | |||
142 | /** |
||
143 | * Gets a new instance of the compiler. |
||
144 | * |
||
145 | * @param string $name |
||
146 | * |
||
147 | * @return \Phar |
||
148 | */ |
||
149 | 1 | protected function getCompiler(string $name): \Phar |
|
161 | |||
162 | /** |
||
163 | * @return $this |
||
164 | */ |
||
165 | 1 | protected function makeBuildsFolder(): Builder |
|
173 | |||
174 | /** |
||
175 | * Sets the executable mode on the single application file. |
||
176 | * |
||
177 | * @param string $name |
||
178 | * |
||
179 | * @return $this |
||
180 | */ |
||
181 | 1 | protected function setPermissions($name): Builder |
|
187 | |||
188 | /** |
||
189 | * @return $this |
||
190 | */ |
||
191 | 1 | protected function prepare(): Builder |
|
209 | |||
210 | /** |
||
211 | * @return $this |
||
212 | */ |
||
213 | 1 | View Code Duplication | protected function clear(): Builder |
223 | |||
224 | /** |
||
225 | * Makes sure that the `clear` is performed even |
||
226 | * if the command fails. |
||
227 | * |
||
228 | * @return void |
||
229 | */ |
||
230 | 20 | View Code Duplication | public function __destruct() |
237 | } |
||
238 |
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: