Update/redirect simple classic wpcom admin interface option update (#…

…37921)

* Simple Classic: Redirect to Default interface after switching wpcom_admin_interface

* changelog

* Fix phan issues

projects/packages/jetpack-mu-wpcom/changelog/update-redirect-simple-classic-wpcom_admin_interface-option-update

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Simple Classic: Redirect to Default interface after switching wpcom_admin_interface

projects/packages/jetpack-mu-wpcom/src/features/wpcom-admin-interface/wpcom-admin-interface.php

@@ -36,14 +36,15 @@ function wpcom_admin_interface_display() {
 	// The option should always be available on atomic sites.
 	! ( defined( 'IS_WPCOM' ) && IS_WPCOM ) ||
 	// The option will be shown if the simple site has already changed to Classic which means they should have already passed the experiment gate.
+	// We can remove the redirection in wpcom_admin_interface_pre_update_option for simple sites after the experiment is finished.
 	( function_exists( 'wpcom_is_nav_redesign_enabled' ) && wpcom_is_nav_redesign_enabled() ) ) {
 	add_action( 'admin_init', 'wpcomsh_wpcom_admin_interface_settings_field' );
 }
 
 /**
  * Track the wpcom_admin_interface_changed event.
  *
- * @param array $value The new value.
+ * @param string $value The new value.
  * @return void
  */
 function wpcom_admin_interface_track_changed_event( $value ) {
@@ -64,9 +65,9 @@ function wpcom_admin_interface_track_changed_event( $value ) {
  * @access private
  * @since 4.20.0
  *
- * @param array $new_value The new settings value.
- * @param array $old_value The old settings value.
- * @return array The value to update.
+ * @param string $new_value The new settings value.
+ * @param string $old_value The old settings value.
+ * @return string The value to update.
  */
 function wpcom_admin_interface_pre_update_option( $new_value, $old_value ) {
 	if ( $new_value === $old_value ) {
@@ -83,6 +84,22 @@ function wpcom_admin_interface_pre_update_option( $new_value, $old_value ) {
 	}
 
 	if ( ( new Automattic\Jetpack\Status\Host() )->is_wpcom_simple() ) {
+		if ( 'calypso' === $new_value ) {
+			// Fixes https://github.com/Automattic/dotcom-forge/issues/7760.
+			// We can remove this code if the related code in wpcom_admin_interface_display is removed.
+			add_action(
+				'update_option_wpcom_admin_interface',
+				/**
+				 * Redirects to the WordPress.com home page when the admin interface is changed to Calypso.
+				 *
+				 * @return never
+				*/
+				function () {
+					wp_safe_redirect( 'https://wordpress.com/home/' . wpcom_get_site_slug() );
+					exit;
+				}
+			);
+		}
 		return $new_value;
 	}