CSV library error using WEBrick

Confirmed on Rails master and Ruby 1.9.2-head.

This is a very strange issue. I used CSV inside a class method on Post model. If I open the rails console, and try Post.foo, it works.

However if I do reload! — it stops working.

The model:

require 'csv'

class Post < ActiveRecord::Base
  def self.foo
    csv_content =  CSV.generate { |csv| }
  end
end

The console output:

Loading development environment (Rails 3.0.0.beta4)
ruby-1.9.2-head > Post.foo
 => "" 
ruby-1.9.2-head > reload!
Reloading...
 => true 
ruby-1.9.2-head > Post.foo
NameError: uninitialized constant Post::CSV
  from /home/rohit/bugmash/trythreadsafe/app/models/post.rb:5:in `foo'
  from (irb):3
  from /home/rohit/remote-repos/rails_patches/working4/railties/lib/rails/commands/console.rb:47:in `start'
  from /home/rohit/remote-repos/rails_patches/working4/railties/lib/rails/commands/console.rb:8:in `start'
  from /home/rohit/remote-repos/rails_patches/working4/railties/lib/rails/commands.rb:23:in `<top (required)>'
  from script/rails:6:in `require'
  from script/rails:6:in `<main>'

Curiously enough, I tried the same thing with YAML, Digest and Zlib and things worked fine. I also tried on a Rails 2.x app on 1.8.7 and things worked.

Can somebody please try on Rails 2.x and 1.9.2-preview3 or -head? Looks like a CSV lib issue on 1.9.2.