_environment.txt

$ ruby --version
ruby 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin10]

$ gem list | grep json
json (1.2.0)
json_pure (1.2.0)

$ gem list | grep activesupport
activesupport (2.3.5)

_fix.rb

# add this line before requiring 'json' or 'active_support':
require 'generator.rb'

# I figured this out by reading:
# https://rails.lighthouseapp.com/projects/8994/tickets/2942-enumerableenumeratornext-causes-stack-level-too-deep-since-activesupport-233

fail_1.rb

require 'rubygems'
require 'ruby-debug'
require 'json'

class Stream
  def initialize
    @data = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
    @iterator = @data.each
  end
  
  def fetch
    @iterator.next
  end
end

def main
  data = Stream.new
  debugger
  loop do
    x = data.fetch
    puts x
  end
end

main

fail_1.txt

$ ruby fail_1.rb 
fail_1.rb:19
loop do
(rdb:1) s
fail_1.rb:20
x = data.fetch
(rdb:1) s
fail_1.rb:12
@iterator.next
(rdb:1) s
fail_1.rb:12:in `next': stack level too deep (SystemStackError)
	from fail_1.rb:12:in `fetch'
	from fail_1.rb:20:in `main'
	from fail_1.rb:19:in `loop'
	from fail_1.rb:19:in `main'
	from fail_1.rb:25

fail_2.rb

require 'rubygems'
require 'ruby-debug'
require 'active_support'

class Stream
  def initialize
    @data = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
    @iterator = @data.each
  end
  
  def fetch
    @iterator.next
  end
end

def main
  data = Stream.new
  debugger
  loop do
    x = data.fetch
    puts x
  end
end

main

fail_2.txt

brooklyn:iter djsun$ ruby fail_2.rb 
fail_2.rb:19
loop do
(rdb:1) s
fail_2.rb:20
x = data.fetch
(rdb:1) s
fail_2.rb:12
@iterator.next
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:84
result = blank_slate_method_added(name)
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:84
result = blank_slate_method_added(name)
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:84
result = blank_slate_method_added(name)
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:84
result = blank_slate_method_added(name)
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:85
return result if self != Object
(rdb:1) s
/Users/djsun/.gem/ruby/1.8/gems/builder-2.1.2/lib/blankslate.rb:84
result = blank_slate_method_added(name)
(rdb:1) 

...

win.rb

class Stream
  def initialize
    @data = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
    @iterator = @data.each
  end
  
  def fetch
    @iterator.next
  end
end

def main
  data = Stream.new
  loop do
    puts data.fetch
  end
end

main

win.txt

1
1
2
3
5
8
13
21
34
55