From 7a86a5a42f8fc2ae8cc76f5914308d6d67d09dd0 Mon Sep 17 00:00:00 2001
From: dmsnell <dmsnell@git.wordpress.org>
Date: Fri, 2 Aug 2024 22:59:12 +0000
Subject: [PATCH] HTML API: Indicate when WordPress rejects attribute updates.

When setting an an attribute value in the HTML API, WordPress may reject
an update based on rules in `kses`. In these cases, the return value from
an escaping function will be an empty string, and the HTML API should
reject the update. Unfortunately, it currently reports that it updates the
attribute but sets an empty string value, which is misleading.

In this patch, the HTML API will refuse the attribute update and return
false to indicate as much when WordPress rejects the updates.

Developed in https://github.com/wordpress/wordpress-develop/pull/7114
Discussed in https://core.trac.wordpress.org/ticket/61719

Follow-up to [58472].

Props: amitraj2203, dmsnell, mukesh27.
Fixes #61719.

Built from https://develop.svn.wordpress.org/trunk@58844


git-svn-id: http://core.svn.wordpress.org/trunk@58240 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/html-api/class-wp-html-tag-processor.php | 6 ++++++
 wp-includes/version.php                              | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/wp-includes/html-api/class-wp-html-tag-processor.php b/wp-includes/html-api/class-wp-html-tag-processor.php
index c619806525..5e2ee114ae 100644
--- a/wp-includes/html-api/class-wp-html-tag-processor.php
+++ b/wp-includes/html-api/class-wp-html-tag-processor.php
@@ -3197,6 +3197,12 @@ class WP_HTML_Tag_Processor {
 			 * @see https://html.spec.whatwg.org/#attributes-3
 			 */
 			$escaped_new_value = in_array( $comparable_name, wp_kses_uri_attributes() ) ? esc_url( $value ) : esc_attr( $value );
+
+			// If the escaping functions wiped out the update, reject it and indicate it was rejected.
+			if ( '' === $escaped_new_value && '' !== $value ) {
+				return false;
+			}
+
 			$updated_attribute = "{$name}=\"{$escaped_new_value}\"";
 		}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0cc490f4b3..98585627f6 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.7-alpha-58843';
+$wp_version = '6.7-alpha-58844';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.