Don't override devise's after_sign_in_path_for, use specific before filters for user sessions and registrations controllers instead

app/controllers/application_controller.rb

@@ -8,15 +8,12 @@ class ApplicationController < ActionController::Base
     super(options, response_status)
   end
 
-  def after_sign_in_path_for(resource)
+  def set_checkout_redirect
     if request.referer and referer_path = URI(request.referer).path
-      [main_app.checkout_path].include?(referer_path) ? referer_path : root_path
-    else
-      root_path
+      session["spree_user_return_to"] = [main_app.checkout_path].include?(referer_path) ? referer_path : root_path
     end
   end
 
-
   private
 
   def require_distributor_chosen

app/controllers/spree/user_sessions_controller_decorator.rb

@@ -1,4 +1,6 @@
 Spree::UserSessionsController.class_eval do
+  before_filter :set_checkout_redirect, only: :create
+
   def create
     authenticate_spree_user!
 

app/controllers/user_registrations_controller.rb

@@ -1,4 +1,5 @@
 class UserRegistrationsController < Spree::UserRegistrationsController
+  before_filter :set_checkout_redirect, only: :create
 
   # POST /resource/sign_up
   def create

spec/controllers/spree/user_sessions_controller_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe Spree::UserSessionsController do
+  include AuthenticationWorkflow
+
+  let(:user) { create_enterprise_user }
+
+  before do
+    @request.env["devise.mapping"] = Devise.mappings[:spree_user]
+  end
+
+  describe "create" do
+    context "succeed" do
+      context "when referer is not '/checkout'" do
+        it "redirects to root" do
+          spree_post :create, spree_user: {email: user.email, password: user.password }, :use_route => :spree
+          response.should redirect_to root_path
+        end
+      end
+
+      context "when referer is '/checkout'" do
+        before { @request.env['HTTP_REFERER'] = 'http://test.com/checkout' }
+
+        it "redirects to checkout" do
+          spree_post :create, spree_user: { email: user.email, password: user.password }, :use_route => :spree
+          response.should redirect_to checkout_path
+        end
+      end
+    end
+  end
+end

spec/controllers/user_registrations_controller_spec.rb

@@ -6,7 +6,7 @@ describe UserRegistrationsController do
   before do
     @request.env["devise.mapping"] = Devise.mappings[:spree_user]
   end
-  
+
   describe "via ajax" do
     render_views
     it "returns errors when registration fails" do
@@ -25,15 +25,31 @@ describe UserRegistrationsController do
     end
   end
 
-  it "renders new when registration fails" do
-    spree_post :create, spree_user: {}
-    response.status.should == 200
-    response.should render_template "spree/user_registrations/new"
+  context "when registration fails" do
+    it "renders new" do
+      spree_post :create, spree_user: {}
+      response.status.should == 200
+      response.should render_template "spree/user_registrations/new"
+    end
   end
 
-  it "redirects when registration succeeds" do
-    spree_post :create, spree_user: {email: "test@test.com", password: "testy123", password_confirmation: "testy123"}, :use_route => :spree
-    response.should be_redirect
-    assigns[:user].email.should == "test@test.com"
+  context "when registration succeeds" do
+    context "when referer is not '/checkout'" do
+      it "redirects to root" do
+        spree_post :create, spree_user: {email: "test@test.com", password: "testy123", password_confirmation: "testy123"}, :use_route => :spree
+        response.should redirect_to root_path
+        assigns[:user].email.should == "test@test.com"
+      end
+    end
+
+    context "when referer is '/checkout'" do
+      before { @request.env['HTTP_REFERER'] = 'http://test.com/checkout' }
+
+      it "redirects to checkout" do
+        spree_post :create, spree_user: {email: "test@test.com", password: "testy123", password_confirmation: "testy123"}, :use_route => :spree
+        response.should redirect_to checkout_path
+        assigns[:user].email.should == "test@test.com"
+      end
+    end
   end
 end