Merge "Feature flag language button in main page header"

includes/Constants.php

@@ -251,6 +251,31 @@ final class Constants {
 	 */
 	public const CONFIG_SEARCH_TREATMENT_AB_TEST = 'VectorSearchTreatmentABTest';
 
+	/**
+	 * @var string
+	 */
+	public const REQUIREMENT_IS_MAIN_PAGE = 'IsMainPage';
+
+	/**
+	 * @var string
+	 */
+	public const REQUIREMENT_LANGUAGE_IN_MAIN_PAGE_HEADER = 'LanguageInMainPageHeader';
+
+	/**
+	 * @var string
+	 */
+	public const CONFIG_LANGUAGE_IN_MAIN_PAGE_HEADER = 'VectorLanguageInMainPageHeader';
+
+	/**
+	 * @var string
+	 */
+	public const QUERY_PARAM_LANGUAGE_IN_MAIN_PAGE_HEADER = 'languageinmainpageheader';
+
+	/**
+	 * @var string
+	 */
+	public const FEATURE_LANGUAGE_IN_MAIN_PAGE_HEADER = 'LanguageInMainPageHeader';
+
 	/**
 	 * This class is for namespacing constants only. Forbid construction.
 	 * @throws FatalError

includes/ServiceWiring.php

@@ -135,6 +135,37 @@ return [
 			]
 		);
 
+		// Feature: T293470: Language in main page header
+		// ================================
+		$featureManager->registerRequirement(
+			new OverridableConfigRequirement(
+				$services->getMainConfig(),
+				$context->getUser(),
+				$context->getRequest(),
+				null,
+				Constants::CONFIG_LANGUAGE_IN_MAIN_PAGE_HEADER,
+				Constants::REQUIREMENT_LANGUAGE_IN_MAIN_PAGE_HEADER,
+				Constants::QUERY_PARAM_LANGUAGE_IN_MAIN_PAGE_HEADER,
+				null
+			)
+		);
+
+		$featureManager->registerSimpleRequirement(
+			Constants::REQUIREMENT_IS_MAIN_PAGE,
+			$context->getTitle() ? $context->getTitle()->isMainPage() : false
+		);
+
+		$featureManager->registerFeature(
+			Constants::FEATURE_LANGUAGE_IN_MAIN_PAGE_HEADER,
+			[
+				Constants::REQUIREMENT_FULLY_INITIALISED,
+				Constants::REQUIREMENT_LATEST_SKIN_VERSION,
+				Constants::REQUIREMENT_IS_MAIN_PAGE,
+				Constants::REQUIREMENT_LANGUAGE_IN_HEADER,
+				Constants::REQUIREMENT_LANGUAGE_IN_MAIN_PAGE_HEADER
+			]
+		);
+
 		// Feature: Use Wvui Search
 		// ================================
 		$featureManager->registerRequirement(

includes/SkinVector.php

@@ -154,15 +154,40 @@ class SkinVector extends SkinMustache {
 	}
 
 	/**
+	 * @param string $location Either 'top' or 'bottom' is accepted.
 	 * @return bool
 	 */
-	private function isLanguagesInHeader() {
+	private function isLanguagesInContentAt( $location ) {
+		if ( !$this->canHaveLanguages() ) {
+			return false;
+		}
 		$featureManager = VectorServices::getFeatureManager();
-		// Disable button on pages without languages (based on Wikibase RepoItemLinkGenerator class)
-
-		return $this->canHaveLanguages() && $featureManager->isFeatureEnabled(
+		$inContent = $featureManager->isFeatureEnabled(
 			Constants::FEATURE_LANGUAGE_IN_HEADER
 		);
+		$isMainPage = $this->getTitle() ? $this->getTitle()->isMainPage() : false;
+
+		switch ( $location ) {
+			case 'top':
+				return $isMainPage ? $inContent && $featureManager->isFeatureEnabled(
+					Constants::FEATURE_LANGUAGE_IN_MAIN_PAGE_HEADER
+				) : $inContent;
+			case 'bottom':
+				return $inContent && $isMainPage && !$featureManager->isFeatureEnabled(
+					Constants::FEATURE_LANGUAGE_IN_MAIN_PAGE_HEADER
+				);
+			default:
+				throw new RuntimeException( 'unknown language button location' );
+		}
+	}
+
+	/**
+	 * Whether or not the languages are out of the sidebar and in the content either at
+	 * the top or the bottom.
+	 * @return bool
+	 */
+	private function isLanguagesInContent() {
+		return $this->isLanguagesInContentAt( 'top' ) || $this->isLanguagesInContentAt( 'bottom' );
 	}
 
 	/**
@@ -174,7 +199,7 @@ class SkinVector extends SkinMustache {
 		return !$this->isLegacy() &&
 			!$this->canHaveLanguages() ||
 			// NOTE: T276950 - This should be revisited when an empty state for the language button is chosen.
-			( $this->isLanguagesInHeader() && empty( $this->getLanguagesCached() ) );
+			( $this->isLanguagesInContent() && empty( $this->getLanguagesCached() ) );
 	}
 
 	/**
@@ -438,7 +463,9 @@ class SkinVector extends SkinMustache {
 
 			'sidebar-visible' => $this->isSidebarVisible(),
 
-			'is-language-in-header' => $this->isLanguagesInHeader(),
+			'is-language-in-content' => $this->isLanguagesInContent(),
+			'is-language-in-content-top' => $this->isLanguagesInContentAt( 'top' ),
+			'is-language-in-content-bottom' => $this->isLanguagesInContentAt( 'bottom' ),
 
 			'data-search-box' => $this->getSearchData(
 				$parentData['data-search-box'],
@@ -706,7 +733,7 @@ class SkinVector extends SkinMustache {
 				break;
 		}
 
-		if ( $portletData['id'] === 'p-lang' && $this->isLanguagesInHeader() ) {
+		if ( $portletData['id'] === 'p-lang' && $this->isLanguagesInContent() ) {
 			$portletData = array_merge( $portletData, $this->getULSPortletData() );
 		}
 		$class = $portletData['class'];
@@ -738,7 +765,7 @@ class SkinVector extends SkinMustache {
 				$type = self::MENU_TYPE_DEFAULT;
 				break;
 			case 'lang':
-				$type = $this->isLanguagesInHeader() ?
+				$type = $this->isLanguagesInContent() ?
 					self::MENU_TYPE_DROPDOWN : self::MENU_TYPE_PORTAL;
 				break;
 			default:

includes/templates/Sidebar.mustache

@@ -18,7 +18,7 @@
 	</div>
 	{{/data-emphasized-sidebar-action}}
 	{{#array-portlets-rest}}{{>Menu}}{{/array-portlets-rest}}
-	{{^is-language-in-header}}
+	{{^is-language-in-content}}
 	{{#data-portlets.data-languages}}{{>Menu}}{{/data-portlets.data-languages}}
-	{{/is-language-in-header}}
+	{{/is-language-in-content}}
 </div>

includes/templates/skin.mustache

@@ -51,28 +51,28 @@
 	<a id="top"></a>
 	<div id="siteNotice">{{{html-site-notice}}}</div>
 
-	{{^is-language-in-header}}
+	{{^is-language-in-content}}
 	{{>Indicators}}
 	<h1 id="firstHeading" class="firstHeading" {{{html-user-language-attributes}}}>{{{html-title}}}</h1>
-	{{/is-language-in-header}}
+	{{/is-language-in-content}}
 
-	{{#is-language-in-header}}
+	{{#is-language-in-content}}
 	<header class="mw-body-header">
-		{{^is-mainpage}}
+		{{#is-language-in-content-top}}
 			{{#data-portlets.data-languages}}{{>Menu}}{{/data-portlets.data-languages}}
-		{{/is-mainpage}}
+		{{/is-language-in-content-top}}
 		<h1 id="firstHeading" class="firstHeading" {{{html-user-language-attributes}}}>{{{html-title}}}</h1>
 		{{>Indicators}}
 		{{#is-article}}
 			<div id="siteSub" class="noprint">{{msg-tagline}}</div>
 		{{/is-article}}
 	</header>
-	{{/is-language-in-header}}
+	{{/is-language-in-content}}
 
 	<div id="bodyContent" class="vector-body">
-		{{^is-language-in-header}}
+		{{^is-language-in-content}}
 			{{#is-article}}<div id="siteSub" class="noprint">{{msg-tagline}}</div>{{/is-article}}
-		{{/is-language-in-header}}
+		{{/is-language-in-content}}
 		<div id="contentSub"{{{html-user-language-attributes}}}>{{{html-subtitle}}}</div>
 		<div id="contentSub2">{{{html-undelete-link}}}</div>
 		{{{html-user-message}}}
@@ -80,11 +80,9 @@
 		{{{html-categories}}}
 	</div>
 
-	{{#is-mainpage}}
-	{{#is-language-in-header}}
-		{{#data-portlets.data-languages}}{{>Menu}}{{/data-portlets.data-languages}}
-	{{/is-language-in-header}}
-	{{/is-mainpage}}
+	{{#is-language-in-content-bottom}}
+	{{#data-portlets.data-languages}}{{>Menu}}{{/data-portlets.data-languages}}
+	{{/is-language-in-content-bottom}}
 
 </main>
 {{{html-after-content}}}

skin.json

@@ -358,6 +358,13 @@
 			},
 			"description": "@var array Moves the language links from the sidebar into a menu beside the page title. Also moves the indicators to the line below, next to the tagline (siteSub)."
 		},
+		"VectorLanguageInMainPageHeader": {
+			"value": {
+				"logged_in": false,
+				"logged_out": false
+			},
+			"description": "@var When `VectorLanguageInHeader` is enabled, determines whether the Main Page's language button should be at the top or bottom of the content. The default position on the main page is at the bottom."
+		},
 		"VectorLanguageInHeaderTreatmentABTest": {
 			"value": false,
 			"description": "@var boolean Enables or disables the language in header treatment A/B test. See https://phabricator.wikimedia.org/T280825 and associated tasks for additional detail."