Add a support of targeting subelements during validation

It seems that there is an issue with the current code that prevents a certain field form being targeted.

The issue is with the !empty($error->arrayPropertyPath) check of the errorElement method that will return false regardless of the real value of arrayPropertyPath property that seems to be fetched through the magic __get method. The solution could be either to define a local variable and use that instead or use the getPropertyPath method instead.

The resulting code would be either

  public function errorElement(array $element, ConstraintViolationInterface $error, array $form, FormStateInterface $form_state) {
    // Validation errors might be a about a specific (behavior) form element
    // attempt to find a matching element.
    $path = $error->arrayPropertyPath;
    if (!empty($path) && $sub_element = NestedArray::getValue($element, $path)) {
      return $sub_element;
    }
    return $element;
  }

or

  public function errorElement(array $element, ConstraintViolationInterface $error, array $form, FormStateInterface $form_state) {
    // Validation errors might be a about a specific (behavior) form element
    // attempt to find a matching element.
    if (!empty($error->getPropertyPath()) && $sub_element = NestedArray::getValue($element, $error->arrayPropertyPath)) {
      return $sub_element;
    }
    return $element;
  }

Hello, you can use "combine" with this patch to make it work. It adds magic method that was removed in the new version of Drupal.

https://www.drupal.org/project/drupal/issues/3359645 🐛 Using $error->arrayPropertyPath returns empty everytime Active

I believe this has been fixed by Stop using $error->arrayPropertyPath (3333974) → and is in release 1.18. Thus I am closing as duplicate.