How to enable Ruby debug in RubyMine 2.0 on Windows

I recently had the chance to evaluate JetBrains' RubyMine. I was well impressed by this IDE except for the impossibility to debug Ruby code.

However I didn't gave up and, googling a bit, I found a thread inside JetBrains Developer Community that helped me to fix my installation and finally to debug Ruby code inside RubyMine.

Although the entire procedure is fully described in that thread, I think is worth summarizing the fundamental steps to fix the environment.

Let's start from a scenario where Ruby 1.9 has been installed with the one-click installer and RubyMine 2.0 has been installed too. (If you installed Ruby with the zip binary, reinstall it using the one-click installer as found here. That's because currently the ruby debugger ide only works on Windows using a RubyInstaller installation). Also verify that Ruby's root path doesn't include spaces.

1. Download Ruby DevKit. (The links brings you to a .7z file, that you can open with 7Zip).
2. Open the .7z file and follow the instructions in INSTALL file: basically they said to extract top-level folders (i.e. bin and devkit) to the Ruby's root folder and to modify the contents of fstab file according to your installation. In my case, my Ruby folder was: C:\programmi\ruby19, so my fstab file contents became:
   C:\Programmi\Ruby19\devkit\gcc\3.4.5\mingw32 /mingw
   C:\Programmi\Ruby19\devkit\msys\1.0.11\usr\local /usr/local
3. Execute the command gem install ruby-debug-ide19
   (Note that's fundamental to install ruby debug ide as ruby-debug-ide19 because RubyMine looks for a gem with name ruby-debug-ide19 and not ruby-debug-ide, as you would expect). Also be patient because the command takes a while to complete.
4. Open with a text editor the file command.rb that's part of the installed ruby-debug-ide19 gem. In my case, that file was under folder C:\Programmi\Ruby19\lib\ruby\gems\1.9.1\gems\ruby-debug-ide19-0.4.12\lib\ruby-debug
5. Modify the beginning of procedure debug_eval (at line 120) so to enter a new statement between statements str = str.to_s and max_time = 10. The new statement to enter is:
   return "" if str == "$FILENAME"
   At the end, the procedure debug_eval should begin like this:
   def debug_eval(str, b = get_binding)
     begin str = str.to_s
     return "" if str == "$FILENAME"
     max_time = 10
     to_inspect = str.gsub(/\\n/, "\n")
6. Save the file

That's it. Enjoy Ruby debugging with RubyMine!