MiniRacer::RuntimeError does not handle multiline error messages correctly

[davidtaylorhq]

begin
  MiniRacer::Context.new.eval('throw new Error("errormessage\nwith\nnewlines")')
rescue => e
  puts e.message
end

This will output

Error: errormessage

The missing lines incorrectly appear as part of e.backtrace:

JavaScript with
JavaScript newlines
JavaScript at <anonymous>:1:7
/Users/david/.rvm/gems/ruby-2.7.3/gems/mini_racer-0.6.3/lib/mini_racer.rb:228:in `eval_unsafe'
/Users/david/.rvm/gems/ruby-2.7.3/gems/mini_racer-0.6.3/lib/mini_racer.rb:228:in `block (2 levels) in eval'
...

The relevant code is:

mini_racer/lib/mini_racer.rb

Lines 44 to 54 in 719abdb

	class RuntimeError < EvalError
	def initialize(message)
	message, js_backtrace = message.split("\n", 2)
	if js_backtrace && !js_backtrace.empty?
	@js_backtrace = js_backtrace.split("\n")
	@js_backtrace.map!{|f| "JavaScript #{f.strip}"}
	else
	@js_backtrace = nil
	end
	super(message)
	end

[tisba]

That's probably a tricky one, good find though, @davidtaylorhq and thx for reporting!

"Parsing" a JavaScript error seems to be a lot more complicated.

There is a special stack trace API (https://v8.dev/docs/stack-trace-api) in V8 that we might be able to hook into. In any case it would be super useful to have more then just the string representation in Ruby-land. Any idea if that would be possible, @SamSaffron? That might also be interesting for #129 and could could help making this way more robust.