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Bug #9055

closed

Global methods called from an object can access object's internals

Added by concorde (Alexander Korolkov) over 10 years ago. Updated over 10 years ago.

Status:
Rejected
Assignee:
-
Target version:
ruby -v:
ruby 2.1.0dev (2013-10-27 trunk 43439) [x86_64-linux]
[ruby-core:58052]

Description

=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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