Get rid of flash hook and clean up passwords after registration.

app/controllers/devise/registrations_controller.rb

@@ -5,7 +5,7 @@ class Devise::RegistrationsController < ApplicationController
 
   # GET /resource/sign_up
   def new
-    build_resource
+    build_resource({})
     render_with_scope :new
   end
 
@@ -14,10 +14,10 @@ class Devise::RegistrationsController < ApplicationController
     build_resource
 
     if resource.save
-      flash[:"#{resource_name}_signed_up"] = true
       set_flash_message :notice, :signed_up
       sign_in_and_redirect(resource_name, resource)
     else
+      clean_up_passwords(resource)
       render_with_scope :new
     end
   end
@@ -33,6 +33,7 @@ class Devise::RegistrationsController < ApplicationController
       set_flash_message :notice, :updated
       redirect_to after_sign_in_path_for(self.resource)
     else
+      clean_up_passwords(resource)
       render_with_scope :edit
     end
   end

app/controllers/devise/sessions_controller.rb

@@ -4,13 +4,10 @@ class Devise::SessionsController < ApplicationController
 
   # GET /resource/sign_in
   def new
-    unless resource_just_signed_up?
-      Devise::FLASH_MESSAGES.each do |message|
-        set_now_flash_message :alert, message if params.try(:[], message) == "true"
-      end
-    end
-
-    build_resource
+    Devise::FLASH_MESSAGES.each do |message|
+      set_now_flash_message :alert, message if params.try(:[], message) == "true"
+    end unless flash[:notice]
+    build_resource({})
     render_with_scope :new
   end
 
@@ -19,6 +16,8 @@ class Devise::SessionsController < ApplicationController
     if resource = authenticate(resource_name)
       set_flash_message :notice, :signed_in
       sign_in_and_redirect(resource_name, resource, true)
+    elsif warden.winning_strategy && warden.result != :failure
+      authenticate!
     else
       set_now_flash_message :alert, (warden.message || :invalid)
       clean_up_passwords(build_resource)
@@ -31,14 +30,4 @@ class Devise::SessionsController < ApplicationController
     set_flash_message :notice, :signed_out if signed_in?(resource_name)
     sign_out_and_redirect(resource_name)
   end
-
-  protected
-
-    def resource_just_signed_up?
-      flash[:"#{resource_name}_signed_up"]
-    end
-
-    def clean_up_passwords(object)
-      object.clean_up_passwords if object.respond_to?(:clean_up_passwords)
-    end
 end