Bug Report

Current Behavior
everytime a null object is tried to unserialize this exception occures.

for example, when calling the cart this exception is thrown:

PHP Runtime Deprecation Notice: unserialize(): Passing null to parameter #1 ($data) of type string is deprecated in /var/website/current/html/typo3conf/ext/cart/Classes/Controller/Cart/CartController.php line 64

Environment

• TYPO3 version(s): 11.5.7
• cart version: 8.2.0
• PHP: 8.1
• Is your TYPO3 installation set up with Composer (Composer Mode): yes
• OS: Debian

Possible Solution
check objects against null before unserialize them like $billingAddress = unserialize($sessionData); would be transformed to $billingAddress = is_null($sessionData) ? null : unserialize($billingAddress);

found sofar inside CartController.php for

$shippingAddress = unserialize($sessionData);

$billingAddress = unserialize($sessionData);