Ticket #36660: 36660.patch

src/wp-includes/class-wp-customize-widgets.php

@@ -1064 +1064 @@
          * @return array
          */
         public function preview_sidebars_widgets( $sidebars_widgets ) {
-                $sidebars_widgets = get_option( 'sidebars_widgets' );
+                $sidebars_widgets = get_option( 'sidebars_widgets', array() );
 
                 unset( $sidebars_widgets['array_version'] );
                 return $sidebars_widgets;