Merge "Work around T87871 to avoid double-loading OOjs UI PHP styles"

includes/OutputPage.php

@@ -4088,5 +4088,8 @@ class OutputPage extends ContextSource {
 			'oojs-ui.styles.textures',
 			'mediawiki.widgets.styles',
 		) );
+		// Used by 'skipFunction' of the four 'oojs-ui.styles.*' modules. Please don't treat this as a
+		// public API or you'll be severely disappointed when T87871 is fixed and it disappears.
+		$this->addMeta( 'X-OOUI-PHP', '1' );
 	}
 }

resources/ResourcesOOUI.php

@@ -68,9 +68,6 @@ return call_user_func( function () {
 			'es5-shim',
 			'oojs',
 			'oojs-ui.styles',
-			'oojs-ui.styles.icons',
-			'oojs-ui.styles.indicators',
-			'oojs-ui.styles.textures',
 			'mediawiki.language',
 		),
 		'targets' => array( 'desktop', 'mobile' ),
@@ -81,6 +78,14 @@ return call_user_func( function () {
 		'styles' => 'resources/src/oojs-ui-local.css', // HACK, see inside the file
 		'skinStyles' => $getSkinSpecific( 'core' ),
 		'targets' => array( 'desktop', 'mobile' ),
+		// ResourceLoaderImageModule doesn't support 'skipFunction', so instead we set this up so that
+		// this module is skipped together with its dependencies. Nothing else depends on these modules.
+		'dependencies' => array(
+			'oojs-ui.styles.icons',
+			'oojs-ui.styles.indicators',
+			'oojs-ui.styles.textures',
+		),
+		'skipFunction' => 'resources/src/oojs-ui-styles-skip.js',
 	);
 
 	// Deprecated old name for the module 'oojs-ui-core.styles'.

resources/src/oojs-ui-styles-skip.js

@@ -0,0 +1,9 @@
+/*!
+ * Skip function for OOjs UI PHP style modules.
+ *
+ * The `<meta name="X-OOUI-PHP" />` is added to pages by OutputPage::enableOOUI().
+ *
+ * Looking for elements in the DOM might be expensive, but it's probably better than double-loading
+ * 200 KB of CSS with embedded images because of bug T87871.
+ */
+return !!jQuery( 'meta[name="X-OOUI-PHP"]' ).length;