Sharpening CIDER’s Debugging Tools

The series on the notable changes in CIDER 2.0 rolls on. This time: the “what is my code actually doing?” toolbox - the debugger, tracing, enlighten, and the new tap viewer. This was the part of the release I enjoyed working on the most, and the part that needed the most love. The debugger, dusted off CIDER’s interactive debugger is one of its most impressive features and, paradoxically, one of its least reliable ones. Instrumenting arbitrary Clojure code is hard - the debugger rewrites your forms to capture locals at every step, and the corner cases are endless. Over the 2.0 cycle (and the 0.62.x releases of cider-nrepl) a whole family of long-standing instrumentation bugs got fixed: Record literals embedded in code survive instrumentation instead of being quietly downgraded to plain maps - which used to break protocol dispatch in anything that compiled routes or components into records (compojure users know the pain). defrecord/deftype inline methods no longer blow up with the…