Debugging/Breakpoint-ing the Rails Core with Ruby-Debug?

Question

How do I debug the rails gems? I've just found the beauty of ruby-debug and am real excited, but I want to step through the routing code in action_controller, but the debugger isn't set up at this time, it seems like it's just skipping over my "debugger" calls in action_controller/routing/route_set.rb for example.

What am I missing?

Answer 1

I just tested this with Rails 2.3.4. I added a 'debugger' line to the call method in vendor/rails/actionpack/lib/action_controller/routing/route_set.rb, ran 'rdebug script/server', browsed to a page, and it stopped at the correct line.

You can also use a class/method breakpoint; you'll need to step through the first few lines of the app until you're past the require 'action_controller' line, and then enter: b ActionController::Routing::RouteSet.call.

Or you can try setting a breakpoint based on the file name and line number.