Bug #13096: error using undef_method + refinements

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 2.3 or 2.4
• Backport: 2.2: DONE, 2.3: DONE, 2.4: DONE

[zenspider (Ryan Davis)]

I've got a bug report on minitest/mock that I've reduced to the following:

class Object
  def to_query            # remove this, works fine
  end
end

Object.prepend Module.new # remove this, works fine

module ObjectExtensions
  refine ::Object do
    def to_query          # remove this, works fine
    end
  end
end

class Mock
  instance_methods.each do |m|
    next if m =~ /object_id|__send__/
    undef_method m
  end
end

giving me the error:

bug671.rb:18:in `undef_method': undefined method `to_query' for class `Mock' (NameError)
	from bug671.rb:18:in `block in <class:Mock>'
	from bug671.rb:16:in `each'
	from bug671.rb:16:in `<class:Mock>'
	from bug671.rb:15:in `<main>'

This code comes from activesupport via regular requires, so this is a real problem for me.

Looks like the culprit might be here:

https://github.com/ruby/ruby/blob/v2_4_0/vm_method.c#L1187

I'd expect to be able to undef anything that comes back from instance_methods regardless of whether there is a refinement in place or not.

Additionally, the error message is just plain wrong. The method is most certainly defined (twice!) and should be improved.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset r57362.

---

vm_method.c: resolve refined method to undef

• vm_method.c (rb_undef): resolve the method entry which refines a
  prepended method entry. [ruby-core:78944] [Bug #13096]

[naruse (Yui NARUSE)]

• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN to 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: DONE

ruby_2_4 r57862 merged revision(s) 57362.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: DONE to 2.2: UNKNOWN, 2.3: REQUIRED, 2.4: DONE

[usa (Usaku NAKAMURA)]

• Backport changed from 2.2: UNKNOWN, 2.3: REQUIRED, 2.4: DONE to 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE

[usa (Usaku NAKAMURA)]

• Backport changed from 2.2: REQUIRED, 2.3: REQUIRED, 2.4: DONE to 2.2: DONE, 2.3: REQUIRED, 2.4: DONE

ruby_2_2 r58126 merged revision(s) 57362.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.2: DONE, 2.3: REQUIRED, 2.4: DONE to 2.2: DONE, 2.3: DONE, 2.4: DONE

ruby_2_3 r58174 merged revision(s) 57362.