Ever spent way longer than you would have liked trying to find out exactly where a particular Ruby object method is defined, especially in something like Rails where a method could have been included from a plugin, gem, helper, or otherwise metaprogrammed in?
Well with Ruby 1.9.3 … you can now do this
and get this back
=> ["/Users/xxx/.rvm/gems/ruby-1.9.3-p362/gems/state_machine-1.1.2/lib/state_machine/machine.rb", 752]
Blew my mind, and I’ve been writing Ruby for almost 6 years now.