Basic Begin-Rescue-Pry Pattern

Sometimes I get an error on a seemingly-random iteration of a loop that occurs many times. Normally I would drop in in a binding.pry from the Pry Ruby gem, but this is not always a sufficient solution, since I’d have to exit through all the successful iterations until I found the error.

The smarter way to do this is to use begin/rescue blocks to ensure binding.pry is only called when (any) error is thrown. Here’s a generic example:

begin 
  # troublesome code where the error is occurring 
rescue
  binding.pry
end

With this code in place, the binding.pry will only be called when the trouble code line or block generates an error of any kind, thus taking you straight to the first problematic iteration.