I accidentally introduced an infinite loop in my app yesterday, and ran into an issue where nginx returned a 502 and puma was completely silent. I finally confirmed it was getting to puma and the rest of my app and spent an entire day digging through my code to see where the SystemStackError was getting rescued and ignored.

Finally I narrowed it down to line 117 of lib/puma/thread_pool.rb. It just rescues Exception and does nothing with it. It isn't even spitting out the error.

This lead to a huge hassle in debugging. Is there something I didn't set up right? Or is this genuinely a bug? (Using the latest version of Grape, Ruby 2.2.3, Rack 1.6.2, on Mac OS X 10.11 if that helps).