resourceloader: Set value for getVary in server-side

This change makes ResourceLoaderStorageVersion a private variable.
The JavaScript global variable wgResourceLoaderStorageVersion is now
removed.

This change makes the JavaScript code smaller.

Change-Id: I8e31b95d4c44ba653bedb6be500011a39bc6abd8

includes/resourceloader/ResourceLoaderStartUpModule.php

@@ -105,7 +105,6 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 			'wgCaseSensitiveNamespaces' => $caseSensitiveNamespaces,
 			'wgLegalTitleChars' => Title::convertByteClassToUnicodeClass( Title::legalChars() ),
 			'wgIllegalFileChars' => Title::convertByteClassToUnicodeClass( $illegalFileChars ),
-			'wgResourceLoaderStorageVersion' => $conf->get( 'ResourceLoaderStorageVersion' ),
 			'wgResourceLoaderStorageEnabled' => $conf->get( 'ResourceLoaderStorageEnabled' ),
 			'wgForeignUploadTargets' => $conf->get( 'ForeignUploadTargets' ),
 			'wgEnableUploads' => $conf->get( 'EnableUploads' ),
@@ -367,6 +366,20 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 		return $baseModules;
 	}
 
+	/**
+	 * Get the key on which the JavaScript module cache (mw.loader.store) will vary.
+	 *
+	 * @param ResourceLoaderContext $context
+	 * @return string String of concatenated vary conditions
+	 */
+	private function getStoreVary( ResourceLoaderContext $context ) {
+		return implode( ':', [
+			$context->getSkin(),
+			$this->getConfig()->get( 'ResourceLoaderStorageVersion' ),
+			$context->getLanguage(),
+		] );
+	}
+
 	/**
 	 * @param ResourceLoaderContext $context
 	 * @return string JavaScript code
@@ -399,6 +412,7 @@ class ResourceLoaderStartUpModule extends ResourceLoaderModule {
 			'$VARS.maxQueryLength' => ResourceLoader::encodeJsonForScript(
 				$conf->get( 'ResourceLoaderMaxQueryLength' )
 			),
+			'$VARS.storeVary' => ResourceLoader::encodeJsonForScript( $this->getStoreVary( $context ) ),
 		];
 		$profilerStubs = [
 			'$CODE.profileExecuteStart();' => 'mw.loader.profiler.onExecuteStart( module );',

resources/src/startup/mediawiki.js

@@ -2170,9 +2170,7 @@
 					 * @return {string} String of concatenated vary conditions.
 					 */
 					getVary: function () {
-						return mw.config.get( 'skin' ) + ':' +
-							mw.config.get( 'wgResourceLoaderStorageVersion' ) + ':' +
-							mw.config.get( 'wgUserLanguage' );
+						return $VARS.storeVary;
 					},
 
 					/**