Bug #7475

Updated by Nobuyoshi Nakada about 2 years ago

=begin
A more involved explanation is available at ((<URL:http://erniemiller.org/2012/11/29/ruby-tidbit-include-vs-extend-with-module-class-variables/>)) http://erniemiller.org/2012/11/29/ruby-tidbit-include-vs-extend-with-module-class-variables/

In short, the handling of class variables (and constants) when a module is extended vs included is not as expected.

Example:

module Foo
@@foo = 'foo'
end

class Bar
include Foo
end

class Baz
extend Foo
end

Bar.class_variable_get :@@foo # => "foo"
Baz.singleton_class.class_variable_get :@@foo # => NameError: uninitialized class variable @@foo in Class

We would expect constant and class variable lookup on the singleton class to work, but it doesn't. Both Rubinius and JRuby seem to behave as expected in this case.

Thanks!
=end

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