Only in .: form_error.patch
diff -urp ./includes/form.inc ../drupal-drupal-8d466e1 2/includes/form.inc
--- ./includes/form.inc	2010-09-29 15:12:51.000000000 -0500
+++ ../drupal-drupal-8d466e1 2/includes/form.inc	2010-09-29 16:13:56.000000000 -0500
@@ -3656,7 +3656,7 @@ function _form_set_class(&$element, $cla
   if (!empty($element['#required'])) {
     $element['#attributes']['class'][] = 'required';
   }
-  if (isset($element['#parents']) && form_get_error($element)) {
+  if (isset($element['#parents']) && form_get_error($element) !== NULL) {
     $element['#attributes']['class'][] = 'error';
   }
 }