Invoking byebug inside DelegateClass definition throws the `cannot load such file -- .../core` error.

[Nakilon]

Addressing an undefined method inside initialize throws a cryptic error message:

     ArgumentError:
       not delegated

so to find it out I wanted to use byebug, like this:

require "delegate"
MyClass = DelegateClass(Hash) do
  def initialize

    require "byebug"
    byebug

    undefined_variable_that_caused_error
    super({ 1=>2 })
  end
end
MyClass.new

but it throws:

Traceback (most recent call last):
	8: from temp.rb:10:in `<main>'
	7: from temp.rb:10:in `new'
	6: from temp.rb:5:in `initialize'
	5: from /home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/delegate.rb:86:in `method_missing'
	4: from /home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/delegate.rb:86:in `bind_call'
	3: from /home/.../.rbenv/versions/2.7.8/lib/ruby/gems/2.7.0/gems/byebug-11.1.3/lib/byebug/attacher.rb:36:in `byebug'
	2: from /home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/delegate.rb:86:in `method_missing'
	1: from /home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/delegate.rb:86:in `bind_call'
/home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/delegate.rb:86:in `require_relative': cannot load such file -- /home/.../.rbenv/versions/2.7.8/lib/ruby/2.7.0/core (LoadError)

because there https://github.com/ruby/delegate/blob/1c9f9cb37de9c1baa31dad5f67b00f59b765e22a/lib/delegate.rb#L89 they recall your

byebug/lib/byebug/attacher.rb

Line 36 in 7e73848

require_relative "core"

Not sure who is to blame.

[rellampec]

Also getting this error.

I'm unsure where the method_missing comes from. Apparently from byebug when using require_relative "core" (referring to byebug/core). So something is really going on between delegate and byebug .

A work around. Instead of using byebug, use Byebug.attach and make sure to require byebug/core:

require 'byebug/core'
Byebug.attach

• Although I think it fails to break on the line and it goes at to the end the current block/routine... because byebug wording "token" isn't there if you use this approach.

[Nakilon]

IIRC even binding.irb is bugged inside the def initialize.