Phpstan tool found some deprecation issues, that are not ok for php8.1. All of the same kind: "the return type of method is not covariant with tentative return type of parent method". Php8.1 requires declaration of return type otherwise you will get the deprecation notice.
Problems are located in these files:
crumbs/lib/Container/MultiWildcardData.php
crumbs/lib/Container/MultiWildcardDataIterator.php
crumbs/lib/PluginSystem/PluginMethodIterator.php
Use the #[\ReturnTypeWillChange] attribute to temporarily suppress the error.
The patch will follow in the comment.
Closed: duplicate
2.3
Code
This issue is already being worked on in https://www.drupal.org/project/crumbs/issues/3352603 🐛 PHP 8.1 deprecated notices Needs review . Marking as closed/duplicate to prevent confusion.