From 2cbd9cf75e5da076919f216ded3bbaa92769271f Mon Sep 17 00:00:00 2001
From: Andrea Fercia <a.fercia@gmail.com>
Date: Mon, 22 May 2017 20:29:42 +0000
Subject: [PATCH] Themes: Improve the theme Custom Logo accessibility.

Uses the Site title as fallback value for the Custom Logo alt attribute when the original alt attribute is empty.

Props sami.keijonen, joedolson, sstoqnov, nobremarcos, gma992, LiamMcArthur, jjcomack.
Fixes #38768.

Built from https://develop.svn.wordpress.org/trunk@40817


git-svn-id: http://core.svn.wordpress.org/trunk@40675 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/general-template.php | 23 +++++++++++++++++++----
 wp-includes/version.php          |  2 +-
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index 97468acf2a..687ee25f49 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -888,12 +888,27 @@ function get_custom_logo( $blog_id = 0 ) {
 
 	// We have a logo. Logo is go.
 	if ( $custom_logo_id ) {
+		$custom_logo_attr = array(
+			'class'    => 'custom-logo',
+			'itemprop' => 'logo',
+		);
+
+		/*
+		 * If the logo alt attribute is empty, get the site title and explicitly
+		 * pass it to the attributes used by wp_get_attachment_image().
+		 */
+		$image_alt = get_post_meta( $custom_logo_id, '_wp_attachment_image_alt', true );
+		if ( empty( $image_alt ) ) {
+			$custom_logo_attr['alt'] = get_bloginfo( 'name', 'display' );
+		}
+
+		/*
+		 * If the alt attribute is not empty, there's no need to explicitly pass
+		 * it because wp_get_attachment_image() already adds the alt attribute.
+		 */
 		$html = sprintf( '<a href="%1$s" class="custom-logo-link" rel="home" itemprop="url">%2$s</a>',
 			esc_url( home_url( '/' ) ),
-			wp_get_attachment_image( $custom_logo_id, 'full', false, array(
-				'class'    => 'custom-logo',
-				'itemprop' => 'logo',
-			) )
+			wp_get_attachment_image( $custom_logo_id, 'full', false, $custom_logo_attr )
 		);
 	}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index fe90f2a5be..610f646fc0 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-beta1-40816';
+$wp_version = '4.8-beta1-40817';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.