Deprecation: #94665 - Wincache cache backend

See Issue #94665

Description

The Caching Framework backend implementation TYPO3\CMS\Core\Cache\Backend\WincacheBackend is not maintained since Microsoft dropped its support: A PHP 7.4 compatible version came long after PHP 7.4 release and there are no PHP 8.0 works in sight. This backend in general found relatively little use and can be substituted with the well maintained ApcuBackend key/value store on Windows platforms.

WincacheBackend has been marked as deprecated and should not be used anymore.

Impact

The implementation has been marked as deprecated, usages trigger a PHP E_USER_DEPRECATED error.

Affected Installations

Some instances hosted on Windows platform may use this cache backend. This can be verified in the backend “Configuration” module, section “TYPO3_CONF_VARS”, searching for string “WincacheBackend”.

Migration

TYPO3 cache backend configuration is usually done in LocalConfiguration.php. Affected instances could switch to ApcuBackend if the apcu PHP module is loaded, or alternatively to some other backend like RedisBackend, MemcachedBackend or Typo3DatabaseBackend, depending on the specific cache size and usage characteristics.

LocalConfiguration.php example before:

'SYS' => [
    'caching' => [
        'cacheConfigurations' => [
            'aCache' => [
                'backend' => 'TYPO3\\CMS\\Core\\Cache\\Backend\\WincacheBackend',
...

LocalConfiguration.php example after:

'SYS' => [
    'caching' => [
        'cacheConfigurations' => [
            'aCache' => [
                'backend' => 'TYPO3\\CMS\\Core\\Cache\\Backend\\ApcuBackend',
...

In case this cache backend is still used for whatever reason and can’t be dropped easily, the class should be copied to an own extension having an own namespace. The instance configuration needs to be adapted accordingly.