clojurewerkz/cassaforte — pull request #34 by AeroNotix (2014-02-12 21:49:15+00:00)
Title: Check for an invalid *default-session*.

Otherwise execute fails with a distant error with an irrelevant
stacktrace.

This cannot break backwards compatibility because it failed with the
exact same exception, it just catches it earlier and inserts a more
helpful error message.