Symfony version(s) affected

6.0.0+

Description

#42025 added types to all private properties, including Psr16Cache::$createCacheItem. The constructor will only set this property if the $pool also implements Symfony\Component\Cache\Adapter\AdapterInterface. However, later on in set() and setMultiple(), the Psr16Cache attempts to check if $createCacheItem is null - this triggers the following uncaught Error:

Typed property Symfony\Component\Cache\Psr16Cache::$createCacheItem must not be accessed before initialization

As a result, this class does not work with non-Symfony cache pool instances since 6.0.0.

How to reproduce

Instantiate a new Psr16Cache with anything that implements CacheItemPoolInterface but not AdapterInterface. For example:

use Symfony\Component\Cache\Psr16Cache;
use Symfony\Component\Cache\Tests\Fixtures\ExternalAdapter;

$cache = new Psr16Cache(new ExternalAdapter());
$cache->set('foo', 'bar');

Possible Solution

Making Psr16Cache::$createCacheItem nullable would fix this issue.

Additional Context

No response