wow eventually tracked it down , and still can’t explain the differences between my app and a luminus template app that i added the offending code to , essentially for some reason in my app compojure dragging in clout which drags in instaparse which for some reason tries to open “whitespace = #‘\s+‘” with io/reader , and turns out i’d overridden default reader for Strings with some java.nio stuff to make them into Paths which blows up

nice, definetely weird that different hosts had different results though

i’ll just write this off as a 2day exercise in head scratching and move on 😉