Hello,

I am holding deployment of 1.33.0-wmf.4 to the Wikimedia infrastructure. Some code path attempts to retrieve a memcached entry using an empty string as a key. It is most probably going to cause major issues if we keep pushing the train.

The task is: https://phabricator.wikimedia.org/T209429

memcached error: A BAD KEY WAS PROVIDED/CHARACTERS OUT OF RANGE

It originates from MemcachedPeclBagOStuff::checkResult() which logs an error albeit without any context. Probably adding an exception context would give us a stacktrace and thus find the faulting code.