From ae0605b32343ae059d3584850f796aacd35d7c32 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Thu, 21 Mar 2019 10:36:22 +0000
Subject: [PATCH] Accessibility: Introduce `category_list_link_attributes`
 filter in `Walker_Category::start_el()` for the HTML attributes applied to a
 category list item's anchor element.

This complements the `page_menu_link_attributes` filter in `Walker_Page::start_el()` and the `nav_menu_link_attributes` filter in `Walker_Nav_Menu::start_el()`.

Props pbiron, audrasjb, afercia.
Fixes #40666. See #40359.

git-svn-id: https://develop.svn.wordpress.org/trunk@44957 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-walker-category.php | 40 ++++++++++++++++++++---
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/wp-includes/class-walker-category.php b/src/wp-includes/class-walker-category.php
index 7b13264b95..c881e68045 100644
--- a/src/wp-includes/class-walker-category.php
+++ b/src/wp-includes/class-walker-category.php
@@ -108,7 +108,9 @@ class Walker_Category extends Walker {
 			return;
 		}
 
-		$link = '<a href="' . esc_url( get_term_link( $category ) ) . '" ';
+		$atts         = array();
+		$atts['href'] = get_term_link( $category );
+
 		if ( $args['use_desc_for_title'] && ! empty( $category->description ) ) {
 			/**
 			 * Filters the category description for display.
@@ -118,11 +120,40 @@ class Walker_Category extends Walker {
 			 * @param string $description Category description.
 			 * @param object $category    Category object.
 			 */
-			$link .= 'title="' . esc_attr( strip_tags( apply_filters( 'category_description', $category->description, $category ) ) ) . '"';
+			$atts['title'] = strip_tags( apply_filters( 'category_description', $category->description, $category ) );
 		}
 
-		$link .= '>';
-		$link .= $cat_name . '</a>';
+		/**
+		 * Filters the HTML attributes applied to a category list item's anchor element.
+		 *
+		 * @since 5.2.0
+		 *
+		 * @param array   $atts {
+		 *     The HTML attributes applied to the list item's `<a>` element, empty strings are ignored.
+		 *
+		 *     @type string $href  The href attribute.
+		 *     @type string $title The title attribute.
+		 * }
+		 * @param WP_Term $category Term data object.
+		 * @param int     $depth    Depth of category, used for padding.
+		 * @param array   $args     An array of arguments.
+		 * @param int     $id       ID of the current category.
+		 */
+		$atts = apply_filters( 'category_list_link_attributes', $atts, $category, $depth, $args, $id );
+
+		$attributes = '';
+		foreach ( $atts as $attr => $value ) {
+			if ( ! empty( $value ) ) {
+				$value       = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
+				$attributes .= ' ' . $attr . '="' . $value . '"';
+			}
+		}
+
+		$link = sprintf(
+			'<a%s>%s</a>',
+			$attributes,
+			$cat_name
+		);
 
 		if ( ! empty( $args['feed_image'] ) || ! empty( $args['feed'] ) ) {
 			$link .= ' ';
@@ -134,6 +165,7 @@ class Walker_Category extends Walker {
 			$link .= '<a href="' . esc_url( get_term_feed_link( $category->term_id, $category->taxonomy, $args['feed_type'] ) ) . '"';
 
 			if ( empty( $args['feed'] ) ) {
+				/* translators: %s: category name */
 				$alt = ' alt="' . sprintf( __( 'Feed for all posts filed under %s' ), $cat_name ) . '"';
 			} else {
 				$alt   = ' alt="' . $args['feed'] . '"';