Leaking cacheability metadata
After installing CiviCRM 5.45 on a fresh Drupal 9.3.2 running on Ubuntu 20.04.3 LTS, the SAML Authentication module issues a warning after every successful authentication event:
While processing SAML authentication response, code leaked cacheability metadata. This indicates a bug somewhere (but it is hard to pinpoint where): if the same code is called in other scenarios too, it may cause fatal crashes, or bloat the render cache unnecessarily. Please investigate. Metadata: i:6;:O:37:"Drupal\Core\Render\BubbleableMetadata":4:{s:16:"*cacheContexts";a:0:{}s:12:"*cacheTags";a:0:{}s:14:"*cacheMaxAge";i:-1;s:14:"*attachments";a:0:{}}
One of the maintainers of the samlauth
module explains in a corresponding ticket:
the samlauth module isn't leaking metadata. It's detecting that some other code in your website, which was executed during the login process, is leaking metadata and should be fixed.
— roderik, “Code leaked cacheability metadata”, comment #4
Before installing CiviCRM, no warnings appeared in the log, therefore I'd say the appearance of the warnings somehow correspond to the fact that CiviCRM has been installed: CiviCRM code for Drupal might leak cacheability metadata.