From 252e14ac27345eaaff75de44555403c1798db3ee Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Sun, 25 Aug 2019 21:31:43 +0000
Subject: [PATCH] Menus: In `wp_setup_nav_menu_item()` and
 `Walker_Nav_Menu_Edit::start_el()`, check if the post or term associated with
 the menu item still exists to avoid a PHP notice.

If the associated post or term no longer exists, mark the menu item as invalid.

Props mehulkaklotar, kamrankhorsandi, cristiano.zanca, SergeyBiryukov.
Fixes #31703.

git-svn-id: https://develop.svn.wordpress.org/trunk@45891 602fd350-edb4-49c9-b593-d223f7449a82
---
 .../includes/class-walker-nav-menu-edit.php   | 11 +++--
 src/wp-includes/nav-menu.php                  | 46 +++++++++++++------
 2 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/src/wp-admin/includes/class-walker-nav-menu-edit.php b/src/wp-admin/includes/class-walker-nav-menu-edit.php
index 9782618a7e..29f579ab93 100644
--- a/src/wp-admin/includes/class-walker-nav-menu-edit.php
+++ b/src/wp-admin/includes/class-walker-nav-menu-edit.php
@@ -71,14 +71,17 @@ class Walker_Nav_Menu_Edit extends Walker_Nav_Menu {
 		);
 
 		$original_title = false;
+
 		if ( 'taxonomy' == $item->type ) {
-			$original_title = get_term_field( 'name', $item->object_id, $item->object, 'raw' );
-			if ( is_wp_error( $original_title ) ) {
-				$original_title = false;
+			$original_object = get_term( (int) $item->object_id, $item->object );
+			if ( $original_object && ! is_wp_error( $original_title ) ) {
+				$original_title = $original_object->name;
 			}
 		} elseif ( 'post_type' == $item->type ) {
 			$original_object = get_post( $item->object_id );
-			$original_title  = get_the_title( $original_object->ID );
+			if ( $original_object ) {
+				$original_title = get_the_title( $original_object->ID );
+			}
 		} elseif ( 'post_type_archive' == $item->type ) {
 			$original_object = get_post_type_object( $item->object );
 			if ( $original_object ) {
diff --git a/src/wp-includes/nav-menu.php b/src/wp-includes/nav-menu.php
index 98584eac8a..62bdbbf939 100644
--- a/src/wp-includes/nav-menu.php
+++ b/src/wp-includes/nav-menu.php
@@ -819,33 +819,40 @@ function wp_setup_nav_menu_item( $menu_item ) {
 					$menu_item->_invalid = true;
 				}
 
-				$menu_item->url = get_permalink( $menu_item->object_id );
-
 				$original_object = get_post( $menu_item->object_id );
-				/** This filter is documented in wp-includes/post-template.php */
-				$original_title = apply_filters( 'the_title', $original_object->post_title, $original_object->ID );
+
+				if ( $original_object ) {
+					$menu_item->url = get_permalink( $original_object->ID );
+					/** This filter is documented in wp-includes/post-template.php */
+					$original_title = apply_filters( 'the_title', $original_object->post_title, $original_object->ID );
+				} else {
+					$menu_item->url      = '';
+					$original_title      = '';
+					$menu_item->_invalid = true;
+				}
 
 				if ( '' === $original_title ) {
 					/* translators: %d: ID of a post */
-					$original_title = sprintf( __( '#%d (no title)' ), $original_object->ID );
+					$original_title = sprintf( __( '#%d (no title)' ), $menu_item->object_id );
 				}
 
-				$menu_item->title = '' == $menu_item->post_title ? $original_title : $menu_item->post_title;
+				$menu_item->title = ( '' === $menu_item->post_title ) ? $original_title : $menu_item->post_title;
 
 			} elseif ( 'post_type_archive' == $menu_item->type ) {
 				$object = get_post_type_object( $menu_item->object );
 				if ( $object ) {
-					$menu_item->title      = '' == $menu_item->post_title ? $object->labels->archives : $menu_item->post_title;
+					$menu_item->title      = ( '' === $menu_item->post_title ) ? $object->labels->archives : $menu_item->post_title;
 					$post_type_description = $object->description;
 				} else {
-					$menu_item->_invalid   = true;
 					$post_type_description = '';
+					$menu_item->_invalid   = true;
 				}
 
 				$menu_item->type_label = __( 'Post Type Archive' );
 				$post_content          = wp_trim_words( $menu_item->post_content, 200 );
-				$post_type_description = '' == $post_content ? $post_type_description : $post_content;
+				$post_type_description = ( '' === $post_content ) ? $post_type_description : $post_content;
 				$menu_item->url        = get_post_type_archive_link( $menu_item->object );
+
 			} elseif ( 'taxonomy' == $menu_item->type ) {
 				$object = get_taxonomy( $menu_item->object );
 				if ( $object ) {
@@ -855,14 +862,23 @@ function wp_setup_nav_menu_item( $menu_item ) {
 					$menu_item->_invalid   = true;
 				}
 
-				$term_url       = get_term_link( (int) $menu_item->object_id, $menu_item->object );
-				$menu_item->url = ! is_wp_error( $term_url ) ? $term_url : '';
+				$original_object = get_term( (int) $menu_item->object_id, $menu_item->object );
 
-				$original_title = get_term_field( 'name', $menu_item->object_id, $menu_item->object, 'raw' );
-				if ( is_wp_error( $original_title ) ) {
-					$original_title = false;
+				if ( $original_object && ! is_wp_error( $original_object ) ) {
+					$menu_item->url = get_term_link( (int) $menu_item->object_id, $menu_item->object );
+					$original_title = $original_object->name;
+				} else {
+					$menu_item->url      = '';
+					$original_title      = '';
+					$menu_item->_invalid = true;
 				}
-				$menu_item->title = '' == $menu_item->post_title ? $original_title : $menu_item->post_title;
+
+				if ( '' === $original_title ) {
+					/* translators: %d: ID of a term */
+					$original_title = sprintf( __( '#%d (no title)' ), $menu_item->object_id );
+				}
+
+				$menu_item->title = ( '' === $menu_item->post_title ) ? $original_title : $menu_item->post_title;
 
 			} else {
 				$menu_item->type_label = __( 'Custom Link' );