Ticket #21876: 21876.4.diff

src/wp-includes/theme.php

@@ -1204 +1204 @@
  * @since 3.0.0
  *
  * @param string|array $header The header string id (key of array) to remove, or an array thereof.
- * @return True on success, false on failure.
+ * @return bool True on success, false on failure.
  */
 function unregister_default_headers( $header ) {
         global $_wp_default_headers;
         if ( is_array( $header ) ) {
-                array_map( 'unregister_default_headers', $header );
+                $results = array_map( 'unregister_default_headers', $header ); 
+                return ! in_array( false, $results, true );
         } elseif ( isset( $_wp_default_headers[ $header ] ) ) {
                 unset( $_wp_default_headers[ $header ] );
                 return true;