Fix remember me always extending the period

Now the config `extend_remember_period` is used to:

`true` - Every time the user authentication is validated, the
cookie expiration is updated.
`false` - Does not updates the cookie expiration.

Closes #3994

lib/devise.rb

@@ -116,7 +116,6 @@ module Devise
   mattr_accessor :remember_for
   @@remember_for = 2.weeks
 
-  # TODO: extend_remember_period is no longer used
   # If true, extends the user's remember period when remembered via cookie.
   mattr_accessor :extend_remember_period
   @@extend_remember_period = false

lib/devise/models/rememberable.rb

@@ -39,7 +39,7 @@ module Devise
     module Rememberable
       extend ActiveSupport::Concern
 
-      attr_accessor :remember_me, :extend_remember_period
+      attr_accessor :remember_me
 
       def self.required_fields(klass)
         [:remember_created_at]
@@ -71,6 +71,10 @@ module Devise
         self.class.remember_for.from_now
       end
 
+      def extend_remember_period
+        self.class.extend_remember_period
+      end
+
       def rememberable_value
         if respond_to?(:remember_token)
           remember_token
@@ -152,9 +156,6 @@ module Devise
           end
         end
 
-        private
-
-        # TODO: extend_remember_period is no longer used
         Devise::Models.config(self, :remember_for, :extend_remember_period, :rememberable_options, :expire_all_remember_me_on_sign_out)
       end
     end

lib/devise/strategies/rememberable.rb

@@ -25,8 +25,7 @@ module Devise
         end
 
         if validate(resource)
-          remember_me(resource)
-          extend_remember_me_period(resource)
+          remember_me(resource) if extend_remember_me?(resource)
           resource.after_remembered
           success!(resource)
         end
@@ -43,10 +42,8 @@ module Devise
 
     private
 
-      def extend_remember_me_period(resource)
-        if resource.respond_to?(:extend_remember_period=)
-          resource.extend_remember_period = mapping.to.extend_remember_period
-        end
+      def extend_remember_me?(resource)
+        resource.respond_to?(:extend_remember_period) && resource.extend_remember_period
       end
 
       def remember_me?

test/integration/rememberable_test.rb

@@ -92,7 +92,6 @@ class RememberMeTest < ActionDispatch::IntegrationTest
     assert_response :success
     assert warden.authenticated?(:user)
     assert warden.user(:user) == user
-    assert_match /remember_user_token[^\n]*HttpOnly/, response.headers["Set-Cookie"], "Expected Set-Cookie header in response to set HttpOnly flag on remember_user_token cookie."
   end
 
   test 'remember the user before sign up and redirect them to their home' do
@@ -118,6 +117,40 @@ class RememberMeTest < ActionDispatch::IntegrationTest
     end
   end
 
+  test 'extends remember period when extend remember period config is true' do
+    swap Devise, extend_remember_period: true, remember_for: 1.year do
+      user = create_user_and_remember
+      old_remember_token = nil
+
+      travel_to 1.day.ago do
+        get root_path
+        old_remember_token = request.cookies['remember_user_token']
+      end
+
+      get root_path
+      current_remember_token = request.cookies['remember_user_token']
+
+      refute_equal old_remember_token, current_remember_token
+    end
+  end
+
+  test 'does not extend remember period when extend period config is false' do
+    swap Devise, extend_remember_period: false, remember_for: 1.year do
+      user = create_user_and_remember
+      old_remember_token = nil
+
+      travel_to 1.day.ago do
+        get root_path
+        old_remember_token = request.cookies['remember_user_token']
+      end
+
+      get root_path
+      current_remember_token = request.cookies['remember_user_token']
+
+      assert_equal old_remember_token, current_remember_token
+    end
+  end
+
   test 'do not remember other scopes' do
     create_user_and_remember
     get root_path