From: "concorde (Alexander Korolkov)" <telgnik@...>
Date: 2013-10-28T00:21:45+09:00
Subject: [ruby-core:58052] [ruby-trunk - Bug #9055][Open] Global methods	called from an object can access object's internals


Issue #9055 has been reported by concorde (Alexander Korolkov).

----------------------------------------
Bug #9055: Global methods called from an object can access object's internals
https://bugs.ruby-lang.org/issues/9055

Author: concorde (Alexander Korolkov)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: current: 2.1.0
ruby -v: ruby 2.1.0dev (2013-10-27 trunk 43439) [x86_64-linux]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


=begin
When I run the following program:

 def foo()
     bar(1)
     puts "baz: #{@baz}"
 end

 def bar(n)
     puts "global bar: #{n}"
 end

 class X
     def initialize()
         @baz = 42
         foo()
     end
     def bar(n)
         puts "X::bar: #{n}"
     end
 end

 foo()
 X.new()

I expect that foo() will be called once directly and once indirectly from X constructor. So I expect the following output:

 global bar: 1
 baz:
 global bar: 1
 baz:

But in reality I get the following output:

 global bar: 1
 baz:
 X::bar: 1
 baz: 42

So when the method foo() is called from a method of object, it runs in the context of this object! It can access instance variables (@baz) and calls object's method bar() instead of global method bar().

What is this, a bug or a hidden feature? It's never mentioned in ruby tutorials or documentation. This behavior is counter-intuitive and may be potentially dangerous.

The same happens in latest ruby-trunk, ruby-1.8 and ruby-1.9. 
=end


-- 
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