From: Yuki Sonoda <redmine@...>
Date: 2010-10-15T17:16:58+09:00
Subject: [ruby-core:32797] [Ruby 1.9-Bug#3949][Open] Can predefined classes be removed?

Bug #3949: Can predefined classes be removed?
http://redmine.ruby-lang.org/issues/show/3949

Author: Yuki Sonoda
Status: Open, Priority: Normal
Assigned to: Yukihiro Matsumoto, Category: core
ruby -v: ruby 1.6.8 (2005-09-21) [i386-darwin9.1.0]

According to rdoc, Module#remove_const cannot remove predefined classes:

> Predefined classes and singleton objects (such as true) cannot be
> removed.

But actually we can remove them.
$ ruby-1.8.0 -ve 'Object.send(:remove_const, :String); p String'
 ruby 1.8.0 (2003-08-04) [i686-darwin]
 -e:1: uninitialized constant String (NameError)
$ ruby-1.8.1 -ve 'Object.send(:remove_const, :String); p String'
ruby 1.8.1 (2003-12-25) [i686-darwin]
-e:1: uninitialized constant String (NameError)
...
$ ruby-1.9.1 -ve 'Object.send(:remove_const, :String); p String'
ruby 1.9.1p427 (2010-05-23 revision 27982) [i386-darwin9.8.0]
-e:1:in `<main>': uninitialized constant String (NameError)
$ ruby-1.9.2 -ve 'Object.send(:remove_const, :String); p String'
ruby 1.9.2p6 (2010-08-18 revision 29252) [i386-darwin9.8.0]
-e:1:in `<main>': uninitialized constant Object::String (NameError)

The rdoc seems to be describing Ruby 1.6:

ruby-1.6 -ve 'Object.send(:remove_const, :String); p String'  
$ ruby 1.6.8 (2005-09-21) [i386-darwin9.1.0]
 -e:1:in `remove_const': cannot remove Object::String (NameError)
 	from -e:1:in `send'
 	from -e:1

This limitation is intended?  or is the rdoc wrong?  I think we should be able to remove any class on our own risk.


----------------------------------------
http://redmine.ruby-lang.org