DOMElement::setAttribute(): Passing null to parameter #2 ($value) of type string is deprecated on PHP 8.1

Attached is a patch against 2.0.x-dev/2.0.2.

Note that the patch adds filtering of the attribute value based on \Drupal\Core\Template\AttributeString::__toString(), only using Html::escape() directly since it was already used anyway, and a check, if the value is not empty. Technically, the first hunk of the patch should be enough to fix the bug.

Fixed.

Thanks!

Automatically closed - issue fixed for 2 weeks with no activity.