Merge "Add feature flag for sticky table of contents"

includes/Constants.php

@@ -296,6 +296,26 @@ final class Constants {
 	 */
 	public const FEATURE_LANGUAGE_ALERT_IN_SIDEBAR = 'LanguageAlertInSidebar';
 
+	/**
+	 * @var string
+	 */
+	public const REQUIREMENT_TABLE_OF_CONTENTS = 'TableOfContents';
+
+	/**
+	 * @var string
+	 */
+	public const CONFIG_TABLE_OF_CONTENTS = 'VectorTableOfContents';
+
+	/**
+	 * @var string
+	 */
+	public const QUERY_PARAM_TABLE_OF_CONTENTS = 'tableofcontents';
+
+	/**
+	 * @var string
+	 */
+	public const FEATURE_TABLE_OF_CONTENTS = 'TableOfContents';
+
 	/**
 	 * This class is for namespacing constants only. Forbid construction.
 	 * @throws FatalError

includes/ServiceWiring.php

@@ -191,6 +191,30 @@ return [
 			]
 		);
 
+		// Feature: T297610: Table of Contents
+		// ================================
+		$featureManager->registerRequirement(
+			new OverridableConfigRequirement(
+				$services->getMainConfig(),
+				$context->getUser(),
+				$context->getRequest(),
+				null,
+				Constants::CONFIG_TABLE_OF_CONTENTS,
+				Constants::REQUIREMENT_TABLE_OF_CONTENTS,
+				Constants::QUERY_PARAM_TABLE_OF_CONTENTS,
+				null
+			)
+		);
+
+		$featureManager->registerFeature(
+			Constants::FEATURE_TABLE_OF_CONTENTS,
+			[
+				Constants::REQUIREMENT_FULLY_INITIALISED,
+				Constants::REQUIREMENT_LATEST_SKIN_VERSION,
+				Constants::REQUIREMENT_TABLE_OF_CONTENTS
+			]
+		);
+
 		// Feature: Use Wvui Search
 		// ================================
 		$featureManager->registerRequirement(

includes/SkinVector.php

@@ -461,6 +461,16 @@ class SkinVector extends SkinMustache {
 		return $featureManager->isFeatureEnabled( Constants::FEATURE_LANGUAGE_ALERT_IN_SIDEBAR );
 	}
 
+	/**
+	 * Determines if the Table of Contents should be visible.
+	 *
+	 * @return bool
+	 */
+	private function isTableOfContentsVisible(): bool {
+		$featureManager = VectorServices::getFeatureManager();
+		return $featureManager->isFeatureEnabled( Constants::FEATURE_TABLE_OF_CONTENTS );
+	}
+
 	/**
 	 * @inheritDoc
 	 */
@@ -498,6 +508,8 @@ class SkinVector extends SkinMustache {
 			'is-language-in-content-top' => $this->isLanguagesInContentAt( 'top' ),
 			'is-language-in-content-bottom' => $this->isLanguagesInContentAt( 'bottom' ),
 
+			'is-vector-table-of-contents-visible' => $this->isTableOfContentsVisible(),
+
 			'data-search-box' => $this->getSearchData(
 				$parentData['data-search-box'],
 				!$this->isLegacy(),

includes/templates/TableOfContents.mustache

@@ -0,0 +1,3 @@
+<div id="mw-panel-toc" class="mw-sidebar">
+	<!-- sticky TOC goes here -->
+</div>

includes/templates/skin.mustache

@@ -43,6 +43,9 @@
 	{{#sidebar-visible}}checked{{/sidebar-visible}}>
 
 {{>Header}}
+
+{{#is-vector-table-of-contents-visible}}{{>TableOfContents}}{{/is-vector-table-of-contents-visible}}
+
 <div class="mw-workspace-container">
 	{{>Navigation}}
 	<div class="mw-content-container">

skin.json

@@ -420,6 +420,13 @@
 		"VectorDisableSidebarPersistence": {
 			"value": false,
 			"description": "@var boolean Temporary feature flag that disables saving the sidebar expanded/collapsed state as a user-preference (triggered via clicking the main menu icon). This is intended as a temporary kill-switch in the event that the DB is overloaded with writes to the user_options table."
+		},
+		"VectorTableOfContents": {
+			"value": {
+				"logged_in": false,
+				"logged_out": false
+			},
+			"description": "@var When `VectorTableOfContents` is enabled, the sticky table of contents is shown."
 		}
 	},
 	"ServiceWiringFiles": [