Question

I want to alter the way error messages and their backtrace are displayed without rescue-ing the errors and calling a custom method. Is there a way to do this? Is there a method that is called when error messages are displayed which can be overridden? If it is a built-in part of Ruby, can someone point me to the relevant C code that formats the error messages and the backtrace?

Answer 1

matugm’s answer to a question that samuil linked pointed me to the way. I can do this:

at_exit do
  print_the_altered_error_message($!) if $! and !$!.kind_of?(SystemExit)
  $stderr.reopen(IO::NULL)
end

This will not be effective for syntax errors, but for most other cases, it will work.