Use inflector to avoid conflicts.

lib/devise.rb

@@ -317,7 +317,8 @@ module Devise
 
     if options[:model]
       path = (options[:model] == true ? "devise/models/#{module_name}" : options[:model])
-      Devise::Models.send(:autoload, module_name.to_s.camelize.to_sym, path)
+      camelized = ActiveSupport::Inflector.camelize(module_name.to_s)
+      Devise::Models.send(:autoload, camelized.to_sym, path)
     end
 
     Devise::Mapping.add_module module_name

lib/devise/failure_app.rb

@@ -101,7 +101,9 @@ module Devise
 
     def recall_app(app)
       controller, action = app.split("#")
-      "#{controller.camelize}Controller".constantize.action(action)
+      controller_name  = ActiveSupport::Inflector.camelize(controller)
+      controller_klass = ActiveSupport::Inflector.constantize("#{controller_name}Controller")
+      controller_klass.action(action)
     end
 
     def warden

lib/devise/omniauth.rb

@@ -14,8 +14,9 @@ OmniAuth.config.path_prefix = nil
 
 OmniAuth.config.on_failure = Proc.new do |env|
   env['devise.mapping'] = Devise::Mapping.find_by_path!(env['PATH_INFO'], :path)
-  controller_klass = "#{env['devise.mapping'].controllers[:omniauth_callbacks].camelize}Controller"
-  controller_klass.constantize.action(:failure).call(env)
+  controller_name  = ActiveSupport::Inflector.camelize(env['devise.mapping'].controllers[:omniauth_callbacks])
+  controller_klass = ActiveSupport::Inflector.constantize("#{controller_name}Controller")
+  controller_klass.action(:failure).call(env)
 end
 
 module Devise

lib/devise/rails/warden_compat.rb

@@ -28,7 +28,7 @@ class Warden::SessionSerializer
     klass, id, salt = keys
 
     begin
-      record = klass.constantize.to_adapter.get(id)
+      record = ActiveSupport::Inflector.constantize(klass).to_adapter.get(id)
       record if record && record.authenticatable_salt == salt
     rescue NameError => e
       if e.message =~ /uninitialized constant/

lib/devise/strategies/authenticatable.rb

@@ -157,7 +157,8 @@ module Devise
       # becomes simply :database.
       def authenticatable_name
         @authenticatable_name ||=
-          self.class.name.split("::").last.underscore.sub("_authenticatable", "").to_sym
+          ActiveSupport::Inflector.underscore(self.class.name.split("::").last).
+            sub("_authenticatable", "").to_sym
       end
     end
   end

test/devise_test.rb

@@ -58,9 +58,6 @@ class DeviseTest < ActiveSupport::TestCase
     assert_equal :fruits, Devise::CONTROLLERS[:kivi]
     Devise::ALL.delete(:kivi)
     Devise::CONTROLLERS.delete(:kivi)
-
-    assert_nothing_raised(Exception) { Devise.add_module(:authenticatable_again, :model => 'devise/model/authenticatable') }
-    assert defined?(Devise::Models::AuthenticatableAgain)
   end
   
   test 'should complain when comparing empty or different sized passes' do