From ce5e63c224fd7b192556e16ea2b09ebf43360765 Mon Sep 17 00:00:00 2001
From: Dion Hulse <dd32@git.wordpress.org>
Date: Mon, 12 Dec 2016 01:56:53 +0000
Subject: [PATCH] Customize: Fix inability to delete nav menus by preventing
 `preview` filters from being added during `customize_save` admin ajax
 request.

Also prevent setting `nav_menu_locations[...]` values to `NaN` which gets sent as `null`.

Props westonruter.
See #30937, [38810].
Merges [39558] to the 4.7 branch.
Fixes #39103.



git-svn-id: https://develop.svn.wordpress.org/branches/4.7@39570 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/js/customize-nav-menus.js           |  6 +++++-
 src/wp-includes/class-wp-customize-nav-menus.php | 15 +++++++--------
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/wp-admin/js/customize-nav-menus.js b/src/wp-admin/js/customize-nav-menus.js
index b7556f6702..a37d2c4e79 100644
--- a/src/wp-admin/js/customize-nav-menus.js
+++ b/src/wp-admin/js/customize-nav-menus.js
@@ -1169,7 +1169,11 @@
 
 			// @todo It would be better if this was added directly on the setting itself, as opposed to the control.
 			control.setting.validate = function( value ) {
-				return parseInt( value, 10 );
+				if ( '' === value ) {
+					return 0;
+				} else {
+					return parseInt( value, 10 );
+				}
 			};
 
 			// Edit menu button.
diff --git a/src/wp-includes/class-wp-customize-nav-menus.php b/src/wp-includes/class-wp-customize-nav-menus.php
index ca1b72f7eb..49c92198fa 100644
--- a/src/wp-includes/class-wp-customize-nav-menus.php
+++ b/src/wp-includes/class-wp-customize-nav-menus.php
@@ -531,10 +531,7 @@ final class WP_Customize_Nav_Menus {
 	 */
 	public function customize_register() {
 
-		/*
-		 * Preview settings for nav menus early so that the sections and controls will be added properly.
-		 * See https://github.com/xwp/wp-customize-snapshots/blob/962586659688a5b1fd9ae93618b7ce2d4e7a421c/php/class-customize-snapshot-manager.php#L506-L543
-		 */
+		// Preview settings for nav menus early so that the sections and controls will be added properly.
 		$nav_menus_setting_ids = array();
 		foreach ( array_keys( $this->manager->unsanitized_post_values() ) as $setting_id ) {
 			if ( preg_match( '/^(nav_menu_locations|nav_menu|nav_menu_item)\[/', $setting_id ) ) {
@@ -542,10 +539,12 @@ final class WP_Customize_Nav_Menus {
 			}
 		}
 		$this->manager->add_dynamic_settings( $nav_menus_setting_ids );
-		foreach ( $nav_menus_setting_ids as $setting_id ) {
-			$setting = $this->manager->get_setting( $setting_id );
-			if ( $setting ) {
-				$setting->preview();
+		if ( ! $this->manager->doing_ajax( 'customize_save' ) ) {
+			foreach ( $nav_menus_setting_ids as $setting_id ) {
+				$setting = $this->manager->get_setting( $setting_id );
+				if ( $setting ) {
+					$setting->preview();
+				}
 			}
 		}