Nav Menus: In `Walker_Nav_Menu_Edit::start_el()` initialize `$original_title` with `false`.

Prevents displaying "Original:" without a title when adding a menu item without a title.

Props grapplerulrich, swissspidy.
Fixes #36729.

git-svn-id: https://develop.svn.wordpress.org/trunk@37953 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-walker-nav-menu-edit.php

@@ -70,7 +70,7 @@ class Walker_Nav_Menu_Edit extends Walker_Nav_Menu {
 			'_wpnonce',
 		);
 
-		$original_title = '';
+		$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 ) )

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

@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @group navmenus
+ * @group walker
+ */
+class Tests_Walker_Nav_Menu_Edit extends WP_UnitTestCase {
+	protected $_wp_nav_menu_max_depth;
+
+	function setUp() {
+		global $_wp_nav_menu_max_depth;
+
+		parent::setUp();
+
+		/** Walker_Nav_Menu_Edit class */
+		require_once( ABSPATH . 'wp-admin/includes/class-walker-nav-menu-edit.php' );
+
+		$this->walker = new Walker_Nav_Menu_Edit();
+
+		$this->_wp_nav_menu_max_depth = $_wp_nav_menu_max_depth;
+	}
+
+	function tearDown() {
+		global $_wp_nav_menu_max_depth;
+
+		$_wp_nav_menu_max_depth = $this->_wp_nav_menu_max_depth;
+
+		parent::tearDown();
+	}
+
+	/**
+	 * @ticket 36729
+	 */
+	function test_original_title_prefix_should_not_be_shown_if_empty() {
+		$expected = '';
+
+		$post_id = $this->factory->post->create();
+
+		$item = array(
+			'classes'          => array(),
+			'description'      => '',
+			'ID'               => $post_id,
+			'menu_item_parent' => 0,
+			'menu_order'       => 0,
+			'object_id'        => $post_id,
+			'object'           => 'post',
+			'post_excerpt'     => get_the_excerpt( $post_id ),
+			'title'            => get_the_title( $post_id ),
+			'type'             => 'foobar',
+			'type_label'       => 'Foo Bar',
+			'target'           => '_blank',
+			'url'              => '',
+			'xfn'              => '',
+		);
+
+		$this->walker->start_el( $expected, (object) $item );
+
+		$this->assertNotRegExp( '#<p class="link-to-original">\s*Original: <a href=""></a>#', $expected );
+	}
+}