From: noreply@...
Date: 2007-03-22T19:19:10+09:00
Subject: [ ruby-Bugs-9462 ] BUGS in metaclasses inheritance

Bugs item #9462, was opened at 22/03/2007 11:19
You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1698&aid=9462&group_id=426

Category: Core
Group: 1.8.x
Status: Open
Resolution: None
Priority: 3
Submitted By: Chauk-Mean P (chauk-mean)
Assigned to: Nobody (None)
Summary: BUGS in metaclasses inheritance

Initial Comment:
 
The inheritance between metaclasses (noted between parentheses) should be as defined in the object.c source code (best seen with a fixed font) :

 *                            +------------------+
 *                            |                  |
 *              Object---->(Object)              |
 *               ^  ^        ^  ^                | 
 *               |  |        |  |                |
 *               |  |  +-----+  +---------+      |
 *               |  |  |                  |      |
 *               |  +-----------+         |      |
 *               |     |        |         |      | 
 *        +------+     |     Module--->(Module)  |
 *        |            |        ^         ^      |
 *   OtherClass-->(OtherClass)  |         |      |
 *                              |         |      | 
 *                            Class---->(Class)  |
 *                              ^                |
 *                              |                |
 *                              +----------------+
 *
 
 
The following code and output show that the actual inheritance between the metaclasses is incorrect :

def inspect_class name, obj
  puts "#################"
  puts "class : #{name} - id : #{obj.object_id}"
  puts "superclass : #{obj.superclass.name } - id : #{obj.superclass.object_id}" if obj.superclass
  puts "#################"
end
class OtherClass
end

class Object
  inspect_class self.name, self
end

class << Object
  inspect_class "(Object)", self
end

class Module
  inspect_class self.name, self
end

class << Module
  inspect_class "(Module)", self
end

class Class
  inspect_class self.name, self
end

class << Class
  inspect_class "(Class)", self
end

class OtherClass
  inspect_class self.name, self
end

class << OtherClass
  inspect_class "(OtherClass)", self
end


The output :

#################
class : Object - id : 22251190
#################
#################
class : (Object) - id : 22251160
superclass : Class - id : 22251170
#################
#################
class : Module - id : 22251180 
superclass : Object - id : 22251190
#################
#################
class : (Module) - id : 22251150
superclass : Class - id : 22251170
#################
#################
class : Class - id : 22251170 
superclass : Module - id : 22251180
#################
#################
class : (Class) - id : 22251140
superclass :  - id : 22251140
#################
#################
class : OtherClass - id : 24175280 
superclass : Object - id : 22251190
#################
#################
class : (OtherClass) - id : 24175220
superclass :  - id : 22251140
#################


The bugs :
- The superclass of (OtherClass) is (Class) instead of (Object) !
- The superclass of (Class) is (Class) instead of (Module) !
- The superclass of (Module) is (Class) instead of (Object) !

Chauk-Mean.


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You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=1698&aid=9462&group_id=426