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 // phpcs:ignore WordPress.Files.FileName |
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18 | class Test_Autoloader_Scenarios extends TestCase { |
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19 | |||
20 | /** |
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21 | * Indicates whether or not the autoloader has been reset by a load operation. |
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22 | * |
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23 | * @var bool |
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24 | */ |
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25 | private $autoloader_reset; |
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26 | |||
27 | /** |
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28 | * Setup runs before each test. |
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29 | * |
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30 | * @before |
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31 | */ |
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32 | public function set_up() { |
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33 | // We need to make sure there's an autoloader containing the current files for testing. |
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34 | $this->generate_autoloader( 'plugin_current' ); |
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35 | $this->generate_autoloader( 'plugin_newer' ); |
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36 | } |
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37 | |||
38 | /** |
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39 | * Teardown runs after each test. |
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40 | * |
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41 | * @after |
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42 | */ |
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43 | public function tear_down() { |
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44 | cleanup_test_wordpress_data(); |
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45 | |||
46 | // Make sure all of the tests have no cache file. |
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47 | // phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged |
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48 | @unlink( TEST_DATA_PATH . '/cache/jetpack-autoloader-' . Plugins_Handler::TRANSIENT_KEY . '.json' ); |
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49 | @rmdir( TEST_DATA_PATH . '/cache' ); |
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50 | // phpcs:enable WordPress.PHP.NoSilencedErrors.Discouraged |
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51 | } |
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52 | |||
53 | /** |
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54 | * Tests that the autoloader works as expected. |
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55 | */ |
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56 | public function test_autoloader_init() { |
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66 | |||
67 | /** |
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68 | * Tests that the autoloader does not initialize twice. |
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69 | */ |
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70 | public function test_autoloader_init_once() { |
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82 | |||
83 | /** |
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84 | * Tests that the autoloader loads the latest when loading an older one first. |
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85 | */ |
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86 | View Code Duplication | public function test_autoloader_loads_latest() { |
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99 | |||
100 | /** |
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101 | * Tests that the autoloader does not conflict with a v1 autoloader. |
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102 | */ |
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103 | public function test_autoloader_overrides_v1() { |
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116 | |||
117 | /** |
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118 | * Tests that the autoloader is not reset when an older V2 initializes after the latest. |
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119 | */ |
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120 | View Code Duplication | public function test_autoloader_not_reset_by_older_v2() { |
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133 | |||
134 | /** |
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135 | * Tests that the autoloader resets when an unknown plugin is encountered, and that it does not |
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136 | * reset a second time once the unknown plugin has been recorded. |
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137 | */ |
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138 | public function test_autoloader_resets_when_unknown_plugin_is_encountered() { |
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150 | |||
151 | /** |
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152 | * Tests that the autoloader uses the cache to avoid resetting when an known plugin is encountered. |
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153 | */ |
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154 | View Code Duplication | public function test_autoloader_uses_cache_to_avoid_resets() { |
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169 | |||
170 | /** |
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171 | * Tests that the autoloader updates the cache. |
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172 | */ |
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173 | public function test_autoloader_updates_cache() { |
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185 | |||
186 | /** |
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187 | * Tests that the autoloader does not update the cache if it has not changed. |
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188 | */ |
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189 | public function test_autoloader_does_not_update_unchanged_cache() { |
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206 | |||
207 | /** |
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208 | * Tests that the autoloader empties the cache if shutdown happens before plugins_loaded. |
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209 | */ |
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210 | public function test_autoloader_empties_cache_on_early_shutdown() { |
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224 | |||
225 | /** |
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226 | * Generates a new autoloader from the current source files for the "plugin_current" plugin. |
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227 | * |
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228 | * @param string $plugin The plugin to generate the autoloader for. |
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229 | */ |
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230 | private function generate_autoloader( $plugin ) { |
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249 | |||
250 | /** |
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251 | * "Activate" a plugin so that the autoloader can detect it. |
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252 | * |
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253 | * @param string $plugin The plugin we want to activate. |
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254 | */ |
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255 | private function activate_plugin( $plugin ) { |
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265 | |||
266 | /** |
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267 | * Loads the given autoloader and initializes it. |
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268 | * |
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269 | * @param string $plugin The plugin to load the autoloader from. |
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270 | */ |
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271 | private function load_autoloader( $plugin ) { |
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285 | |||
286 | /** |
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287 | * Writes the plugins to the cache so that they can be read by the autoloader. |
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288 | * |
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289 | * @param string[] $plugins The plugins to cache. |
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290 | */ |
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291 | private function cache_plugins( $plugins ) { |
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302 | |||
303 | /** |
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304 | * Runs the autoloader's shutdown action. |
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305 | * |
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306 | * @param bool $plugins_loaded Indicates whether or not the plugins_loaded action should have fired. |
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307 | */ |
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308 | private function shutdown_autoloader( $plugins_loaded = true ) { |
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315 | |||
316 | /** |
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317 | * Asserts that the latest autoloader version is the one given. |
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318 | * |
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319 | * @param string $version The version to check. |
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320 | */ |
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321 | private function assertAutoloaderVersion( $version ) { |
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328 | |||
329 | /** |
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330 | * Asserts that the autoloader cache contains the plugins given. |
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331 | * |
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332 | * @param array $plugins The plugins to check the cache for. |
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333 | */ |
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334 | private function assertAutoloaderCache( $plugins ) { |
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348 | } |
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349 |
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: