From: John Higgins <wishdev@...>
Date: 2011-07-12T04:26:58+09:00
Subject: [ruby-core:38007] [Ruby 1.9 - Bug #5015] method_added" is called in addition to "method_undefined


Issue #5015 has been updated by John Higgins.


Lazaridis Ilias wrote:
> John Higgins wrote:
> > Lazaridis Ilias wrote:
> > > John Higgins wrote:
> > > [...]
> > > 
> > > Mr. Higgins, you could write a book in your non-technical tenor about this issue, the fact remains:
> > > 
> > > * callback: added     any_method # false callback, "any_method" was *not* added by user
> > 
> > Would you care to, even in passing, explain how I'm incorrect when it comes to the Child class example I gave? 
> [...]
> 
> No, I can't, because it is irrelevant (and thus I do not invest any energy to analyse). I've provided a use-case. In context of this use-case, the callback "method_added :capitalize" is false, and thus a defect. There's really no need to change context or use-cases: the defect in this use-case remains.

Again, what are you basing this on? I asked you what rule/concept states that internal implementations cannot fire callbacks. Why is it an error if the implementation of undef_method adds a method to the class? Where is the definition of undef_method that states anything about its implementation? In fact the docs state only the following "Prevents the current class from responding to calls to the named method." - why exactly is that at odds with a method_added callback being fired during the execution of an undef_method call?

Would you only call this a bug in a class with a "direct" definition of a method (i.e. non-inherited method). What about the user that wants to track the addition of the "blocking" method to the subclass if you wanted the method_added subclass suppressed even in a subclass without a direct definition of a method?
----------------------------------------
Bug #5015: method_added" is called in addition to "method_undefined
http://redmine.ruby-lang.org/issues/5015

Author: Lazaridis Ilias
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: 1.9.2


When a method is undefined via "undef_method :any_method", the following methods are called back:

* method_added 
* method_undefined

The expected behaviour is that only "method_undefined" is called (similar to "remove_method").

-

class String

  def self.method_added(id)
    puts "callback: added     #{id.id2name}"
  end
  
  def self.method_undefined(id)
    puts "callback: undefined #{id.id2name}"
  end
  
  def self.method_removed(id)  
    puts "callback: removed   #{id.id2name}"
  end
  
end

puts "\nundef method (buildin)"
class String
  undef_method :capitalize
end

puts "\ndefine method"
class String
  def any_method(*args)
    nil
  end
end
    
puts "\nundef method"
class String
  undef_method :any_method
end


puts "\ndefine method"
class String
  def any_method(*args)
    nil
  end
end

puts "\nremove method"
class String
  remove_method :any_method
end



-

OUTPUT:


undef method (buildin)
callback: added     capitalize
callback: undefined capitalize

define method
callback: added     any_method

undef method
callback: added     any_method
callback: undefined any_method

define method
callback: added     any_method

remove method
callback: removed   any_method



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