Rails 4, phantom ArgumentError: wrong number of arguments (0 for 1) on UserSession.find for AuthLogic

This was a total pain to locate, as the exceptions being raised were pointed to UserSession.find in Authlogic::Session::Persistence. gems in question: activerecord-session_store 0.1.1 authlogic 3.4.6 activerecord 4.2.3 rails 4.2.3 I noticed that the only meaningful difference between the two environments was the following instance variable in Rails.application.config: irb> pp Rails.application.config . . . @logger= # […]