Ruby error handling approaches

ruby-errors.rb

def foo
  raise ArgumentError.new("bad arg yo")
end

def bar
  begin
    foo
  # good
  # rescue ArgumentError => e
    # raise
    # raise e, e.message, e.backtrace
    # raise e
  rescue
    # to preserve backtrace good
    # raise
    # raise $!
    # raise $!, "bad arg yo -- part 2", $!.backtrace
    # raise $!, $!.message, $!.backtrace

    #bad
    # raise $!, "Just smoked the backtrace on existing exception"
    # raise "Just smoked the backtrace and changed the exception type "
    # raise RuntimeError.new($!)
    # raise $!, $!.backtrace
  end
end

def doit
  begin
    bar
  rescue
    puts $!.class
    puts $!
    puts $!.backtrace
  end
end

doit