From: Lazaridis Ilias <ilias@...>
Date: 2011-07-05T00:28:48+09:00
Subject: [ruby-core:37772] [Ruby 1.9 - Bug #4893] Literal Instantiation breaks Object Model


Issue #4893 has been updated by Lazaridis Ilias.


Lazaridis Ilias wrote:
[...]
> I've found the "(singleton_)method_added/removed/undefined group of call-backs, those should be usable to implement the last step (automated activation/deactivation of the flag).

Although it's possible to automatically  activate/deactivate the flag, it seems preferable to require that this is done explicitly by the user.

The explicit setting of "String.call_initialize = true|false" ensures that a users knows what he's doing, and that he is aware about the involved speed loss.

The patch "String_call_initialize_v3b.diff" is the suggested final version.


----------------------------------------
Bug #4893: Literal Instantiation breaks Object Model
http://redmine.ruby-lang.org/issues/4893

Author: Lazaridis Ilias
Status: Rejected
Priority: Normal
Assignee: Yukihiro Matsumoto
Category: 
Target version: 
ruby -v: 1.9.2


#String2.rb 
class String 
  def initialize(val) 
    self.replace(val) 
    puts object_id 
  end 
  def my_method_test 
    'has method <my_method_test>' 
  end 
end 

# command line 
$ irb 
irb(main):001:0> original = String.new("original") 
=> "original" 
irb(main):002:0> load "String2.rb" 
=> true 
irb(main):003:0> altered = String.new("altered") 
21878604 
=> "altered" 
irb(main):004:0> altered.my_method_test 
=> "has method <my_method_test>" 
irb(main):005:0> literal = "literal" 
=> "literal" 
irb(main):006:0> literal.my_method_test 
=> "has method <my_method_test>" 
irb(main):007:0> 

- 

The initialize method is an integral part of the class String. 
From the moment that "String2.rb" is loaded, the initialize method of 
class String has been validly redefined. 

(The behaviour of the String class within the "irb session" is 
altered) 

The altered initialize method is now an integral part of the class 
String. 

The altered String object behaves as expected (responds to 
"my_method_test, initialized via redefined initialize method). 

The String(Literal) object responds to "my_method_test", but it is was 
not initialized with the redefined initialize method. 

- 

The "Literal Instantiation" calls the original (core-C-level) String 
initialize method instead of the redefined one (user-language-level). 
This *breaks* the object model. 





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