Merge "resourceloader: Add Module::getSkins to skip irrelevant modules from startup"

includes/resourceloader/ResourceLoaderModule.php

@@ -56,6 +56,8 @@ abstract class ResourceLoaderModule implements LoggerAwareInterface {
 	protected $name = null;
 	/** @var string[] What client platforms the module targets (e.g. desktop, mobile) */
 	protected $targets = [ 'desktop' ];
+	/** @var string[]|null Skin names */
+	protected $skins = null;
 
 	/** @var array Map of (variant => indirect file dependencies) */
 	protected $fileDeps = [];
@@ -459,6 +461,22 @@ abstract class ResourceLoaderModule implements LoggerAwareInterface {
 		return $this->targets;
 	}
 
+	/**
+	 * Get list of skins for which this module must be available to load.
+	 *
+	 * By default, modules are available to all skins.
+	 *
+	 * This information may be used by the startup module to optimise registrations
+	 * based on the current skin.
+	 *
+	 * @stable to override
+	 * @since 1.39
+	 * @return string[]|null
+	 */
+	public function getSkins(): ?array {
+		return $this->skins;
+	}
+
 	/**
 	 * Get the module's load type.
 	 *

includes/resourceloader/ResourceLoaderStartUpModule.php

@@ -157,6 +157,7 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 		// The getVal() method performs slow Language+UTF logic. (f303bb9360)
 		$target = $context->getRequest()->getRawVal( 'target', 'desktop' );
 		$safemode = $context->getRequest()->getRawVal( 'safemode' ) === '1';
+		$skin = $context->getSkin();
 		// Bypass target filter if this request is Special:JavaScriptTest.
 		// To prevent misuse in production, this is only allowed if testing is enabled server-side.
 		$byPassTargetFilter = $this->getConfig()->get( 'EnableJavaScriptTest' ) && $target === 'test';
@@ -185,9 +186,11 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 		foreach ( $moduleNames as $name ) {
 			$module = $resourceLoader->getModule( $name );
 			$moduleTargets = $module->getTargets();
+			$moduleSkins = $module->getSkins();
 			if (
 				( !$byPassTargetFilter && !in_array( $target, $moduleTargets ) )
 				|| ( $safemode && $module->getOrigin() > ResourceLoaderModule::ORIGIN_CORE_INDIVIDUAL )
+				|| ( $moduleSkins !== null && !in_array( $skin, $moduleSkins ) )
 			) {
 				continue;
 			}

tests/phpunit/includes/resourceloader/ResourceLoaderStartUpModuleTest.php

@@ -280,6 +280,34 @@ mw.loader.register([
         "test.blank",
         ""
     ]
+]);'
+			] ],
+			[ [
+				'msg' => 'Different skin (irrelevant skin modules should not be registered)',
+				'modules' => [
+					'test.blank' => [ 'class' => ResourceLoaderTestModule::class ],
+					'test.skin.fallback' => [
+						'class' => ResourceLoaderTestModule::class,
+						'skins' => [ 'fallback' ],
+					],
+					'test.skin.foo' => [
+						'class' => ResourceLoaderTestModule::class,
+						'skins' => [ 'foo' ],
+					],
+				],
+				'out' => '
+mw.loader.addSource({
+    "local": "/w/load.php"
+});
+mw.loader.register([
+    [
+        "test.blank",
+        ""
+    ],
+    [
+        "test.skin.fallback",
+        ""
+    ]
 ]);'
 			] ],
 			[ [