Ticket #64567: 64567.patch

src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -2843 +2843 @@
         public function get_attribute_names_with_prefix( $prefix ): ?array {
                 if ( self::STATE_MATCHED_TAG !== $this->parser_state || $this->is_closing_tag ) {
                         return null;
                 }
+
+                /*
+                 * Make sure pending class changes are represented as attribute updates
+                 * before reading the current attribute names.
+                 */
+                $this->class_name_updates_to_attributes_updates();
+
                 $comparable = strtolower( $prefix );
-                $matches    = array();
+                $matches    = array();
+
                 foreach ( array_keys( $this->attributes ) as $attr_name ) {
                         if ( str_starts_with( $attr_name, $comparable ) ) {
-                                $matches[] = $attr_name;
+                                $matches[ $attr_name ] = true;
+                        }
+                }
+
+                foreach ( $this->lexical_updates as $name => $update ) {
+                        if ( ! is_string( $name ) ) {
+                                continue;
+                        }
+
+                        if ( ! str_starts_with( $name, $comparable ) ) {
+                                continue;
+                        }
+
+                        if ( '' === $update->text ) {
+                                unset( $matches[ $name ] );
+                                continue;
                         }
+
+                        $matches[ $name ] = true;
                 }
-                return $matches;
+
+                return array_keys( $matches );
         }
 
         /**