From: "matz (Yukihiro Matsumoto)" <matz@...>
Date: 2012-04-10T18:47:13+09:00
Subject: [ruby-core:44260] [ruby-trunk - Bug #4307][Rejected] include fails after undef_method


Issue #4307 has been updated by matz (Yukihiro Matsumoto).

Status changed from Assigned to Rejected

lsegal's comment is right.  undef_methods defies the definition of upper classes, include mixed modules.
So, this is expected behavior.

Matz.

----------------------------------------
Bug #4307: include fails after undef_method
https://bugs.ruby-lang.org/issues/4307#change-25796

Author: adrianomitre (Adriano Mitre)
Status: Rejected
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: 1.9.2
ruby -v: ruby 1.9.2p136 (2010-12-25 revision 30365) [x86_64-linux]


=begin
 After using #undef_method on a method "inherited" from a mixin, reincluding the mixin should redefine it, but that is not what happens.
 
 Please take a look at this short IRB transcript (source attached):
 
 >> module Foo; def foo; 42; end; end
 => nil
 >> Array.class_eval { include Foo }
 => Array
 >> [1].foo
 => 42
 >> Array.class_eval { Foo.instance_methods.each {|m| self.class_eval { undef_method m } } }
 => [:foo]
 >> [1].foo
 NoMethodError: undefined method `foo' for [1]:Array
 	from (irb):5
 	from /home/adriano/.rvm/rubies/ruby-1.9.2-p136/bin/irb:16:in `<main>'
 >> Array.class_eval { include Foo }
 => Array
 >> [1].foo
 NoMethodError: undefined method `foo' for [1]:Array
 	from (irb):7
 	from /home/adriano/.rvm/rubies/ruby-1.9.2-p136/bin/irb:16:in `<main>'
 
 The last command should just return 42, instead of raising a NoMethodError exception.
 
 Note that this also applies to the following Ruby implementations:
   * ruby 1.8.7 (2010-12-23 patchlevel 330) [x86_64-linux]
   * rbx-1.2.0-20101221 [ ]
   * jruby-1.5.6 [ amd64-java 
 
 Thus, it may be a language specification gap, not just an implementation bug.
=end



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