In `Walker_Category`, don't generate list elements for empty cat names.

This change allows the 'list_cats' filter to be used to suppress certain
items in category lists, without creating invalid or superfluous markup.

Props samo9789.
Fixes #16792.
Built from https://develop.svn.wordpress.org/trunk@31025


git-svn-id: http://core.svn.wordpress.org/trunk@31006 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/category-template.php

@@ -996,6 +996,11 @@ class Walker_Category extends Walker {
 			$category
 		);
 
+		// Don't generate an element if the category name is empty.
+		if ( ! $cat_name ) {
+			return;
+		}
+
 		$link = '<a href="' . esc_url( get_term_link( $category ) ) . '" ';
 		if ( $args['use_desc_for_title'] && ! empty( $category->description ) ) {
 			/**

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31024';
+$wp_version = '4.2-alpha-31025';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.