Masterbar: send wpcom user ID to wpcom when attempting to log… (#13777)

* Masterbar: send wpcom user ID to wpcom when attempting to log out

Fixes #13680

Until now, we would send a sync event to WordPress.com anytime someone attempted to log out from a site using the "Sign Out" button in the masterbar.
From now on, we'll only do that when we have info about the connected WordPress.com user linked to that local user, and we'll send their wpcom user ID to WordPress.com so WordPress.com can disconnect them (and no one else) from WordPress.com.

* Masterbar: hook into logout_redirect to handle post logout action

WP 5.3 changed the way logouts worked:
https://core.trac.wordpress.org/changeset/46467

As a result we cannot pull the user's ID as they are logging out via the `wp_logout` filter anymore, because by then their info has already been cleared.

Let's instead hooked into `logout_redirect`, where we still have info about the user that logged out.

modules/masterbar/masterbar.php

@@ -2,6 +2,7 @@
 
 use Automattic\Jetpack\Assets;
 use Automattic\Jetpack\Connection\Client;
+use Automattic\Jetpack\Connection\Manager as Connection_Manager;
 
 require_once dirname( __FILE__ ) . '/rtl-admin-bar.php';
 
@@ -80,7 +81,7 @@ public function __construct() {
 		add_action( 'admin_bar_init', array( $this, 'init' ) );
 
 		// Post logout on the site, also log the user out of WordPress.com.
-		add_action( 'wp_logout', array( $this, 'maybe_logout_user_from_wpcom' ) );
+		add_filter( 'logout_redirect', array( $this, 'maybe_logout_user_from_wpcom' ), 10, 3 );
 	}
 
 	/**
@@ -166,8 +167,12 @@ class_exists( 'Jetpack_AMP_Support' )
 
 	/**
 	 * Log out from WordPress.com when logging out of the local site.
+	 *
+	 * @param string  $redirect_to           The redirect destination URL.
+	 * @param string  $requested_redirect_to The requested redirect destination URL passed as a parameter.
+	 * @param WP_User $user                  The WP_User object for the user that's logging out.
 	 */
-	public function maybe_logout_user_from_wpcom() {
+	public function maybe_logout_user_from_wpcom( $redirect_to, $requested_redirect_to, $user ) {
 		/**
 		 * Whether we should sign out from wpcom too when signing out from the masterbar.
 		 *
@@ -182,8 +187,29 @@ public function maybe_logout_user_from_wpcom() {
 			&& 'masterbar' === $_GET['context'] // phpcs:ignore WordPress.Security.NonceVerification.Recommended
 			&& $masterbar_should_logout_from_wpcom
 		) {
-			do_action( 'wp_masterbar_logout' );
+			/*
+			 * Get the associated WordPress.com User ID, if the user is connected.
+			 */
+			$connection_manager = new Connection_Manager();
+			if ( $connection_manager->is_user_connected( $user->ID ) ) {
+				$wpcom_user_data = $connection_manager->get_connected_user_data( $user->ID );
+				if ( ! empty( $wpcom_user_data['ID'] ) ) {
+					/**
+					 * Hook into the log out event happening from the Masterbar.
+					 *
+					 * @since 5.1.0
+					 * @since 7.9.0 Added the $wpcom_user_id parameter to the action.
+					 *
+					 * @module masterbar
+					 *
+					 * @param int $wpcom_user_id WordPress.com User ID.
+					 */
+					do_action( 'wp_masterbar_logout', $wpcom_user_data['ID'] );
+				}
+			}
 		}
+
+		return $redirect_to;
 	}
 
 	/**

packages/sync/src/modules/class-users.php

@@ -127,7 +127,7 @@ public function init_listeners( $callable ) {
 		add_action( 'jetpack_wp_login', $callable, 10, 3 );
 
 		add_action( 'wp_logout', $callable, 10, 0 );
-		add_action( 'wp_masterbar_logout', $callable, 10, 0 );
+		add_action( 'wp_masterbar_logout', $callable, 10, 1 );
 
 		// Add on init.
 		add_filter( 'jetpack_sync_before_enqueue_jetpack_sync_add_user', array( $this, 'expand_action' ) );