From: oleg.b.antonyan@...
Date: 2016-02-26T09:17:32+00:00
Subject: [ruby-core:74004] [Ruby trunk Bug#12113] Global method inside Delegator causes NameError

Issue #12113 has been reported by Oleg Antonyan.

----------------------------------------
Bug #12113: Global method inside Delegator causes NameError
https://bugs.ruby-lang.org/issues/12113

* Author: Oleg Antonyan
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
----------------------------------------
~~~
def some_func
  puts '12'
end

class Klass < Delegator
  def initialize(obj)
    @obj = obj
  end

  def __getobj__
    @obj
  end

  def func
    some_func #=> /home/oleg/.rbenv/versions/2.3.0/lib64/ruby/2.3.0/delegate.rb:85:in `instance_method': undefined method `some_func' for module `Kernel' (NameError)
  end
end

Klass.new(0).func
~~~
Delegator uses Kernel.instance_method (https://github.com/ruby/ruby/blob/trunk/lib/delegate.rb#L85) but:

~~~
::Kernel.respond_to?(:some_func, true) #=> true
::Kernel.instance_method(:some_func)   #=> `instance_method': undefined method `some_func' for module `Kernel' (NameError)
::Kernel.method(:some_func)            #=> #<Method: Module(Object)#some_func>
~~~

I think there should be Kernel.method instead of instance_method (in Delegator). Otherwise you get respond_to? == true, but cannot use this method and get an error.



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