Restore persistent sidebar

Bug: T305989
Change-Id: I1304c777ad9581cd8b9153ad1e4483e31660857e

includes/Hooks.php

@@ -447,6 +447,25 @@ class Hooks {
 		}
 	}
 
+	/**
+	 * Adds the persistent sidebar hidden API preference.
+	 *
+	 * @param User $user User whose preferences are being modified.
+	 * @param array[] &$prefs Preferences description array, to be fed to a HTMLForm object.
+	 */
+	public static function onGetPreferences( User $user, array &$prefs ) {
+		$config = MediaWikiServices::getInstance()->getMainConfig();
+		$vectorPrefs = [
+			Constants::PREF_KEY_SIDEBAR_VISIBLE => [
+				'type' => 'api',
+				'default' => $config->get(
+					Constants::CONFIG_KEY_DEFAULT_SIDEBAR_VISIBLE_FOR_AUTHORISED_USER
+				),
+			],
+		];
+		$prefs += $vectorPrefs;
+	}
+
 	/**
 	 * Called one time when initializing a users preferences for a newly created account.
 	 *

skin.json

@@ -129,6 +129,7 @@
 		"Vector\\": "includes/"
 	},
 	"Hooks": {
+		"GetPreferences": "Vector\\Hooks::onGetPreferences",
 		"ResourceLoaderSiteModulePages": "Vector\\Hooks::onResourceLoaderSiteModulePages",
 		"ResourceLoaderSiteStylesModulePages": "Vector\\Hooks::onResourceLoaderSiteStylesModulePages",
 		"SkinPageReadyConfig": "Vector\\Hooks::onSkinPageReadyConfig",