Ticket #42121: 42121.2.diff

src/wp-includes/class-wp-customize-nav-menus.php

@@ -597 +597 @@
                 // Attempt to re-map the nav menu location assignments when previewing a theme switch.
                 $mapped_nav_menu_locations = array();
                 if ( ! $this->manager->is_theme_active() ) {
-                        $mapped_nav_menu_locations = wp_map_nav_menu_locations( get_nav_menu_locations(), $this->original_nav_menu_locations );
+                        $theme_mods = get_option( 'theme_mods_' . $this->manager->get_stylesheet(), array() );
+
+                        // If there is no data from a previous activation, start fresh.
+                        if ( empty( $theme_mods['nav_menu_locations'] ) ) {
+                                $theme_mods['nav_menu_locations'] = array();
+                        }
+
+                        $mapped_nav_menu_locations = wp_map_nav_menu_locations( $theme_mods['nav_menu_locations'], $this->original_nav_menu_locations );
                 }
 
                 foreach ( $locations as $location => $description ) {

src/wp-includes/nav-menu.php

@@ -1084 +1084 @@
  * @return array Nav menus mapped to new nav menu locations.
  */
 function wp_map_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations ) {
-        $registered_nav_menus = get_registered_nav_menus();
+        $registered_nav_menus   = get_registered_nav_menus();
+        $new_nav_menu_locations = array_intersect_key( $new_nav_menu_locations, $registered_nav_menus );
 
         // Short-circuit if there are no old nav menu location assignments to map.
         if ( empty( $old_nav_menu_locations ) ) {

tests/phpunit/tests/menu/nav-menu.php

@@ -47 +47 @@
                 $this->assertEquals( $expected_nav_menu_locations, $new_next_theme_nav_menu_locations );
         }
 
+
+        function test_filter_registered_locations() {
+                $this->register_nav_menu_locations( array( 'primary', 'secondary' ) );
+                $old_next_theme_nav_menu_locations = $prev_theme_nav_menu_locations = array(
+                        'primary' => 1,
+                        'secondary' => 2,
+                        'social' => 3,
+                );
+                $new_next_theme_nav_menu_locations = wp_map_nav_menu_locations( $old_next_theme_nav_menu_locations, $prev_theme_nav_menu_locations );
+
+                $expected_nav_menu_locations = array(
+                        'primary' => 1,
+                        'secondary' => 2,
+                );
+                $this->assertEquals( $expected_nav_menu_locations, $new_next_theme_nav_menu_locations );
+        }
+
         /**
          * Locations with the same name should map, switching to a theme not previously-active.
          *