From b02beaf298674695f18768a459212cea95be988a Mon Sep 17 00:00:00 2001
From: Konstantin Obenland <obenland@git.wordpress.org>
Date: Tue, 10 Oct 2017 17:07:31 +0000
Subject: [PATCH] Menus: Limit mapping to registered locations

Weeds out orphaned locations, so their information will not continue to be mapped to future themes.

Fixes #42121.


git-svn-id: https://develop.svn.wordpress.org/trunk@41811 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/nav-menu.php          |  3 ++-
 tests/phpunit/tests/menu/nav-menu.php | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/nav-menu.php b/src/wp-includes/nav-menu.php
index 38ef5c89bc..aff8a54373 100644
--- a/src/wp-includes/nav-menu.php
+++ b/src/wp-includes/nav-menu.php
@@ -1084,7 +1084,8 @@ function _wp_menus_changed() {
  * @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 ) ) {
diff --git a/tests/phpunit/tests/menu/nav-menu.php b/tests/phpunit/tests/menu/nav-menu.php
index ec346da53b..562c866c23 100644
--- a/tests/phpunit/tests/menu/nav-menu.php
+++ b/tests/phpunit/tests/menu/nav-menu.php
@@ -47,6 +47,27 @@ class Tests_Nav_Menu_Theme_Change extends WP_UnitTestCase {
 		$this->assertEquals( $expected_nav_menu_locations, $new_next_theme_nav_menu_locations );
 	}
 
+	/**
+	 * Only registered locations should be mapped and returned.
+	 *
+	 * @covers wp_map_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.
 	 *