# Upgrade 2.1.2 to 2.3.4: A copy of XXX has been removed

**URL:** <https://www.ruby-forum.com/t/upgrade-2-1-2-to-2-3-4-a-copy-of-xxx-has-been-removed/179356>\
**Category:** Rails\
**Created:** [November 23, 2009, 10:30am UTC](https://www.ruby-forum.com/t/upgrade-2-1-2-to-2-3-4-a-copy-of-xxx-has-been-removed/179356 "2009-11-23T10:30:16Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![san](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ba9def/32.png) [@san](https://www.ruby-forum.com/u/san)\
**Post date:** [November 23, 2009, 10:30am UTC](https://www.ruby-forum.com/t/upgrade-2-1-2-to-2-3-4-a-copy-of-xxx-has-been-removed/179356/1 "2009-11-23T10:30:16Z")

</div>

Hi,  
i tried to upgrade from rails 2.1.2 to rails 2.3.4 via:

1. 
# envorinment.rb

RAILS\_GEM\_VERSION = ‘2.3.4’ unless defined? RAILS\_GEM\_VERSION  
2) rake rails:upgrade  
2.1) # envorinment.rb  
config.action\_controller.session\_store = :mem\_cache\_store  
2.2) # starting memcached locally  
memcached -l 127.0.0.1 &  
3) ruby script/server  
4) calling localhost:3000 in the browser  
(map.root :controller =\> ‘users’, :action =\> ‘login’)  
5) i log in anf then i get the following error message:

ArgumentError in Module/toolsController#visibility

A copy of UserController has been removed from the module tree but is  
still active!

RAILS\_ROOT: …  
Application Trace | Framework Trace | Full Trace

/usr/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active\_support/dependencies.rb:414:in  
`load_missing_constant' /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:96:in`const\_missing’  
/home/alexanders/Sites/seolytics/sprint1/app/controllers/user\_controller.rb:269:in  
`current_user' /home/alexanders/Sites/seolytics/sprint1/app/controllers/user_controller.rb:261:in`logged\_in?’

This problem does not appear in production mode.  
But in development mode.  
I can solve the problem by setting “config.cache\_classes = true” in  
development.rb, but its no fun to work with that setting in development  
mode.

Does anyone has ideas how to solve the problem?

Greeting,  
Alexander