Issue #6810 has been updated by fxn (Xavier Noria).


Perry, totally agreed. The way this works and how constant name resolution works should be a well-covered topic. But traditionally it has not been very well documented. In particular the separation between constant and modules/classes is unknown to most people, which I think it is a symptom. I have had to research this topic myself to figure out what is going on.

If I get some time I'd like to self publish a monograph about constants in Ruby, with a second part on constant autoloading in Ruby on Rails.

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Bug #6810: `module A::B; end` is not equivalent to `module A; module B; end; end` with respect to constant lookup (scope)
https://bugs.ruby-lang.org/issues/6810#change-28535

Author: alexeymuranov (Alexey Muranov)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 
ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin10.8.0]


=begin
Is this the expected behavior?  To me it is rather surprising:

 N = 0

 module A
   module B
     def self.f; N; end
   end
   N = 1
 end

 A::B.f # => 1

but

 N = 0

 module A; end

 module A::B
   def self.f; N; end
 end

 module A
   N = 1
 end

 A::B.f # => 0

Even more striking:

 module A
   module B
     def self.f; N; end
   end
 end

 N = 0

 A::B.f # => 0

 A::N = 1

 puts A::B.f # => 1

 A::B::N = 2

 A::B.f # => 2

but

 module A; end

 module A::B
   def self.f; N; end
 end

 N = 0

 A::B.f # => 0

 A::N = 1

 A::B.f # => 0

 A::B::N = 2

 A::B.f # => 2


=end


-- 
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