From: "ernie (Ernie Miller)" <ernie@erniemiller.org>
To: ruby-core@ruby-lang.org
Subject: [ruby-core:50394] [ruby-trunk - Bug #7475] Unexpected behavior of Module#append_features on singleton class
Date: Fri, 30 Nov 2012 22:51:39 +0900 [thread overview]
Message-ID: <redmine.journal-34221.20121130225138@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-7475.20121130105621@ruby-lang.org
Issue #7475 has been updated by ernie (Ernie Miller).
Another quick set of observations from this morning:
class Baz
class << self
Const = 'Const'
@@foo = 'foo'
end
end
Baz.class_variables.inspect # => [:@@foo]
Baz.singleton_class.class_variables.inspect # => []
Baz.singleton_class.class_variable_get :@@foo # => 'foo' ???
Baz.const_get(:Const, false) rescue "Nope." # => 'Nope.'
Baz.singleton_class.const_get(:Const, false) rescue "Nope." # => Const
# Let's try setting it explicitly.
Baz.singleton_class.class_variable_set :@@foo, 'foo'
Baz.singleton_class.class_variables.inspect # => [] -- still "empty"
However, if we extend Foo on Baz, vs opening the singleton class with "class << self", we can class_variable_set on the singleton and see it show up in the list of class variables, vs being empty.
All of this is to say that I think some unexpected weirdness is going on in rb_include_module and/or include_class_new.
----------------------------------------
Bug #7475: Unexpected behavior of Module#append_features on singleton class
https://bugs.ruby-lang.org/issues/7475#change-34221
Author: ernie (Ernie Miller)
Status: Open
Priority: Normal
Assignee:
Category:
Target version: 1.9.3
ruby -v: ruby 1.9.3p327 (2012-11-10 revision 37606) [x86_64-darwin12.2.0]
A more involved explanation is available at 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!
--
http://bugs.ruby-lang.org/
next prev parent reply other threads:[~2012-11-30 13:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-30 1:56 [ruby-core:50356] [ruby-trunk - Bug #7475][Open] Unexpected behavior of Module#append_features on singleton class ernie (Ernie Miller)
2012-11-30 13:51 ` ernie (Ernie Miller) [this message]
2013-02-17 23:52 ` [ruby-core:52405] [ruby-trunk - Bug #7475] " ko1 (Koichi Sasada)
2013-02-18 1:47 ` [ruby-core:52425] " nobu (Nobuyoshi Nakada)
2019-08-15 15:28 ` [ruby-core:94367] [Ruby master Bug#7475] " merch-redmine
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