Fix description in cookies_serializer.rb being corrupted when updating

2 files changed, 3 insertions, 2 deletions

diff --git a/railties/lib/rails/generators/rails/app/app_generator.rb b/railties/lib/rails/generators/rails/app/app_generator.rb
index f4d2aa761b..e9435c946a 100644
--- a/railties/lib/rails/generators/rails/app/app_generator.rb
+++ b/railties/lib/rails/generators/rails/app/app_generator.rb
@@ -103,7 +103,7 @@ module Rails
       end
 
       unless cookie_serializer_config_exist
-        gsub_file 'config/initializers/cookies_serializer.rb', /json/, 'marshal'
+        gsub_file 'config/initializers/cookies_serializer.rb', /json(?!,)/, 'marshal'
       end
 
       unless active_record_belongs_to_required_by_default_config_exist
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 11b795bc9f..44259c80cc 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -210,7 +210,8 @@ class AppGeneratorTest < Rails::Generators::TestCase
       generator = Rails::Generators::AppGenerator.new ["rails"], { with_dispatchers: true }, destination_root: app_root, shell: @shell
       generator.send(:app_const)
       quietly { generator.send(:update_config_files) }
-      assert_file("#{app_root}/config/initializers/cookies_serializer.rb", /Rails\.application\.config\.action_dispatch\.cookies_serializer = :marshal/)
+      assert_file("#{app_root}/config/initializers/cookies_serializer.rb",
+                  /Valid options are :json, :marshal, and :hybrid\.\nRails\.application\.config\.action_dispatch\.cookies_serializer = :marshal/)
     end
   end