class IRB::Irb

def debug_break
  # it means the debug command is executed
  if defined?(DEBUGGER__) && DEBUGGER__.respond_to?(:capture_frames_without_irb)
    # after leaving this initial breakpoint, revert the capture_frames patch
    DEBUGGER__.singleton_class.send(:alias_method, :capture_frames, :capture_frames_without_irb)
    # and remove the redundant method
    DEBUGGER__.singleton_class.send(:undef_method, :capture_frames_without_irb)
  end
end