TYPO3 Core

As Helmut Hummel asked me on the english mailing list to open a bug for this:

After upgrading from 4.4.2 to 4.4.3 all my relevant websites went down only showing

ReflectionException

Class does not exist

error on FE, BE as well as install tool, so none of these were able to load anymore.

Debugging showed it seemed related to the use of Memcached with this configuration:

$TYPO3_CONF_VARS['SYS']['useCachingFramework'] = '1';
$TYPO3_CONF_VARS['SYS']['caching']['cacheConfigurations'] = array (
'cache_hash' => array(
'backend' => 't3lib_cache_backend_MemcachedBackend',
'options' => array(
'servers' => array('localhost:11211'),
)
),
'cache_pages' => array(
'backend' => 't3lib_cache_backend_MemcachedBackend',
'options' => array(
'servers' => array('localhost:11211'),
)
),
'cache_pagesection' => array(
'backend' => 't3lib_cache_backend_MemcachedBackend',
'options' => array(
'servers' => array('localhost:11211'),
)
),
);

Here is what Helmut wrote in the english mailing list:

OK. The default configuration for the frontend is overwritten this way.

I would suggest that you either set it to the variable frontend yourself
or put each configuration you change in one line with the complete
variable "path" like this:

$TYPO3_CONF_VARS['SYS']['caching']['cacheConfigurations']['cache_pages']['backend'] = 't3lib_cache_backend_MemcachedBackend';

At first sight it looked simply like a misconfiguration. But now I know
that making the cache frontend configurable¹ and removing the
default configuration in the cache manager² results in a different
behaviour, when ommitting and overwriting the fronted cache configuration.

Feel free to add a bug report to the bugtracker.

In the meantime you can circumvent the problem by doing the things I
mentioned above.

(issue imported from #M15866)