Use frozen string literal in actionpack/

125 files changed, 252 insertions, 2 deletions

diff --git a/actionpack/lib/abstract_controller.rb b/actionpack/lib/abstract_controller.rb
index 8bd965b198..0477e7f1c9 100644
--- a/actionpack/lib/abstract_controller.rb
+++ b/actionpack/lib/abstract_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_pack"
 require "active_support/rails"
 require "active_support/i18n"
diff --git a/actionpack/lib/abstract_controller/asset_paths.rb b/actionpack/lib/abstract_controller/asset_paths.rb
index e6170228d9..d6ee84b87b 100644
--- a/actionpack/lib/abstract_controller/asset_paths.rb
+++ b/actionpack/lib/abstract_controller/asset_paths.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   module AssetPaths #:nodoc:
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/abstract_controller/base.rb b/actionpack/lib/abstract_controller/base.rb
index bca850c0c0..3761054bb7 100644
--- a/actionpack/lib/abstract_controller/base.rb
+++ b/actionpack/lib/abstract_controller/base.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "error"
 require "active_support/configurable"
 require "active_support/descendants_tracker"
diff --git a/actionpack/lib/abstract_controller/caching.rb b/actionpack/lib/abstract_controller/caching.rb
index 30e3d4426c..ce6b757c3c 100644
--- a/actionpack/lib/abstract_controller/caching.rb
+++ b/actionpack/lib/abstract_controller/caching.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   module Caching
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/abstract_controller/caching/fragments.rb b/actionpack/lib/abstract_controller/caching/fragments.rb
index 14e4a82523..f99b0830b2 100644
--- a/actionpack/lib/abstract_controller/caching/fragments.rb
+++ b/actionpack/lib/abstract_controller/caching/fragments.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   module Caching
     # Fragment caching is used for caching various blocks within
diff --git a/actionpack/lib/abstract_controller/callbacks.rb b/actionpack/lib/abstract_controller/callbacks.rb
index e4400e8704..715d043b4e 100644
--- a/actionpack/lib/abstract_controller/callbacks.rb
+++ b/actionpack/lib/abstract_controller/callbacks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   # = Abstract Controller Callbacks
   #
diff --git a/actionpack/lib/abstract_controller/collector.rb b/actionpack/lib/abstract_controller/collector.rb
index 40ae5aa1ca..297ec5ca40 100644
--- a/actionpack/lib/abstract_controller/collector.rb
+++ b/actionpack/lib/abstract_controller/collector.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_dispatch/http/mime_type"
 
 module AbstractController
diff --git a/actionpack/lib/abstract_controller/error.rb b/actionpack/lib/abstract_controller/error.rb
index 7fafce4dd4..89a54f072e 100644
--- a/actionpack/lib/abstract_controller/error.rb
+++ b/actionpack/lib/abstract_controller/error.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   class Error < StandardError #:nodoc:
   end
diff --git a/actionpack/lib/abstract_controller/helpers.rb b/actionpack/lib/abstract_controller/helpers.rb
index 2e50637c39..35b462bc92 100644
--- a/actionpack/lib/abstract_controller/helpers.rb
+++ b/actionpack/lib/abstract_controller/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/dependencies"
 
 module AbstractController
diff --git a/actionpack/lib/abstract_controller/logger.rb b/actionpack/lib/abstract_controller/logger.rb
index c31ea6c5b5..8d0acc1b5c 100644
--- a/actionpack/lib/abstract_controller/logger.rb
+++ b/actionpack/lib/abstract_controller/logger.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/benchmarkable"
 
 module AbstractController
diff --git a/actionpack/lib/abstract_controller/railties/routes_helpers.rb b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
index 14b574e322..b6e5631a4e 100644
--- a/actionpack/lib/abstract_controller/railties/routes_helpers.rb
+++ b/actionpack/lib/abstract_controller/railties/routes_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   module Railties
     module RoutesHelpers
diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index 1c87739d42..41898c4c2e 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "error"
 require "action_view"
 require "action_view/view_paths"
diff --git a/actionpack/lib/abstract_controller/translation.rb b/actionpack/lib/abstract_controller/translation.rb
index e4ac95df50..666e154e4c 100644
--- a/actionpack/lib/abstract_controller/translation.rb
+++ b/actionpack/lib/abstract_controller/translation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   module Translation
     # Delegates to <tt>I18n.translate</tt>. Also aliased as <tt>t</tt>.
diff --git a/actionpack/lib/abstract_controller/url_for.rb b/actionpack/lib/abstract_controller/url_for.rb
index 72d07b0927..bd74c27d3b 100644
--- a/actionpack/lib/abstract_controller/url_for.rb
+++ b/actionpack/lib/abstract_controller/url_for.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module AbstractController
   # Includes +url_for+ into the host class (e.g. an abstract controller or mailer). The class
   # has to provide a +RouteSet+ by implementing the <tt>_routes</tt> methods. Otherwise, an
diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
index 4e2d67954f..e893507baa 100644
--- a/actionpack/lib/action_controller.rb
+++ b/actionpack/lib/action_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/rails"
 require "abstract_controller"
 require "action_dispatch"
diff --git a/actionpack/lib/action_controller/api.rb b/actionpack/lib/action_controller/api.rb
index 2bfa65021d..ba9af4767e 100644
--- a/actionpack/lib/action_controller/api.rb
+++ b/actionpack/lib/action_controller/api.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_view"
 require "action_controller"
 require_relative "log_subscriber"
diff --git a/actionpack/lib/action_controller/api/api_rendering.rb b/actionpack/lib/action_controller/api/api_rendering.rb
index 3a08d28c39..aca5265313 100644
--- a/actionpack/lib/action_controller/api/api_rendering.rb
+++ b/actionpack/lib/action_controller/api/api_rendering.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module ApiRendering
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 6e195fa359..bbc48e6eb7 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_view"
 require_relative "log_subscriber"
 require_relative "metal/params_wrapper"
diff --git a/actionpack/lib/action_controller/caching.rb b/actionpack/lib/action_controller/caching.rb
index 954265ad97..97775d1dc8 100644
--- a/actionpack/lib/action_controller/caching.rb
+++ b/actionpack/lib/action_controller/caching.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # \Caching is a cheap way of speeding up slow applications by keeping the result of
   # calculations, renderings, and database calls around for subsequent requests.
diff --git a/actionpack/lib/action_controller/form_builder.rb b/actionpack/lib/action_controller/form_builder.rb
index f2656ca894..09d2ac1837 100644
--- a/actionpack/lib/action_controller/form_builder.rb
+++ b/actionpack/lib/action_controller/form_builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # Override the default form builder for all views rendered by this
   # controller and any of its descendants. Accepts a subclass of
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index 5d75393897..14f41eb55f 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   class LogSubscriber < ActiveSupport::LogSubscriber
     INTERNAL_PARAMS = %w(controller action format _method only_path)
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 96c708f45a..457884ea08 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/extract_options"
 require "action_dispatch/middleware/stack"
 require "action_dispatch/http/request"
diff --git a/actionpack/lib/action_controller/metal/basic_implicit_render.rb b/actionpack/lib/action_controller/metal/basic_implicit_render.rb
index cef65a362c..2dc990f303 100644
--- a/actionpack/lib/action_controller/metal/basic_implicit_render.rb
+++ b/actionpack/lib/action_controller/metal/basic_implicit_render.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module BasicImplicitRender # :nodoc:
     def send_action(method, *args)
diff --git a/actionpack/lib/action_controller/metal/conditional_get.rb b/actionpack/lib/action_controller/metal/conditional_get.rb
index 0525252c7c..0d9a0c8c56 100644
--- a/actionpack/lib/action_controller/metal/conditional_get.rb
+++ b/actionpack/lib/action_controller/metal/conditional_get.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/keys"
 
 module ActionController
diff --git a/actionpack/lib/action_controller/metal/cookies.rb b/actionpack/lib/action_controller/metal/cookies.rb
index 44925641a1..ff46966693 100644
--- a/actionpack/lib/action_controller/metal/cookies.rb
+++ b/actionpack/lib/action_controller/metal/cookies.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController #:nodoc:
   module Cookies
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/metal/data_streaming.rb b/actionpack/lib/action_controller/metal/data_streaming.rb
index f839c6f4ce..30234ee304 100644
--- a/actionpack/lib/action_controller/metal/data_streaming.rb
+++ b/actionpack/lib/action_controller/metal/data_streaming.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "exceptions"
 
 module ActionController #:nodoc:
diff --git a/actionpack/lib/action_controller/metal/etag_with_flash.rb b/actionpack/lib/action_controller/metal/etag_with_flash.rb
index 7bd338bd7c..38899e2f16 100644
--- a/actionpack/lib/action_controller/metal/etag_with_flash.rb
+++ b/actionpack/lib/action_controller/metal/etag_with_flash.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # When you're using the flash, it's generally used as a conditional on the view.
   # This means the content of the view depends on the flash. Which in turn means
diff --git a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
index 69c3979a0e..640c75536e 100644
--- a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
+++ b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # When our views change, they should bubble up into HTTP cache freshness
   # and bust browser caches. So the template digest for the current action
diff --git a/actionpack/lib/action_controller/metal/exceptions.rb b/actionpack/lib/action_controller/metal/exceptions.rb
index 175dd9eb9e..f808295720 100644
--- a/actionpack/lib/action_controller/metal/exceptions.rb
+++ b/actionpack/lib/action_controller/metal/exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   class ActionControllerError < StandardError #:nodoc:
   end
diff --git a/actionpack/lib/action_controller/metal/flash.rb b/actionpack/lib/action_controller/metal/flash.rb
index 24d1097ebe..5115c2fadf 100644
--- a/actionpack/lib/action_controller/metal/flash.rb
+++ b/actionpack/lib/action_controller/metal/flash.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController #:nodoc:
   module Flash
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/metal/force_ssl.rb b/actionpack/lib/action_controller/metal/force_ssl.rb
index 73e67573ca..0ba1f9f783 100644
--- a/actionpack/lib/action_controller/metal/force_ssl.rb
+++ b/actionpack/lib/action_controller/metal/force_ssl.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/except"
 require "active_support/core_ext/hash/slice"
 
diff --git a/actionpack/lib/action_controller/metal/head.rb b/actionpack/lib/action_controller/metal/head.rb
index 0c50894bce..bac9bc5e5f 100644
--- a/actionpack/lib/action_controller/metal/head.rb
+++ b/actionpack/lib/action_controller/metal/head.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module Head
     # Returns a response that has no content (merely headers). The options
diff --git a/actionpack/lib/action_controller/metal/helpers.rb b/actionpack/lib/action_controller/metal/helpers.rb
index 913a4b9a04..22c84e440b 100644
--- a/actionpack/lib/action_controller/metal/helpers.rb
+++ b/actionpack/lib/action_controller/metal/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # The \Rails framework provides a large number of helpers for working with assets, dates, forms,
   # numbers and model objects, to name a few. These helpers are available to all templates
diff --git a/actionpack/lib/action_controller/metal/implicit_render.rb b/actionpack/lib/action_controller/metal/implicit_render.rb
index eeb27f99f4..ac0c127cdc 100644
--- a/actionpack/lib/action_controller/metal/implicit_render.rb
+++ b/actionpack/lib/action_controller/metal/implicit_render.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # Handles implicit rendering for a controller action that does not
   # explicitly respond with +render+, +respond_to+, +redirect+, or +head+.
diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
index 2485d27cec..476f0843b2 100644
--- a/actionpack/lib/action_controller/metal/instrumentation.rb
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "benchmark"
 require "abstract_controller/logger"
 
diff --git a/actionpack/lib/action_controller/metal/live.rb b/actionpack/lib/action_controller/metal/live.rb
index a607ee2309..2f4c8fb83c 100644
--- a/actionpack/lib/action_controller/metal/live.rb
+++ b/actionpack/lib/action_controller/metal/live.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_dispatch/http/response"
 require "delegate"
 require "active_support/json"
@@ -295,7 +297,7 @@ module ActionController
       return unless logger
 
       logger.fatal do
-        message = "\n#{exception.class} (#{exception.message}):\n"
+        message = "\n#{exception.class} (#{exception.message}):\n".dup
         message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
         message << "  " << exception.backtrace.join("\n  ")
         "#{message}\n\n"
diff --git a/actionpack/lib/action_controller/metal/mime_responds.rb b/actionpack/lib/action_controller/metal/mime_responds.rb
index 96bd548268..2233b93406 100644
--- a/actionpack/lib/action_controller/metal/mime_responds.rb
+++ b/actionpack/lib/action_controller/metal/mime_responds.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "abstract_controller/collector"
 
 module ActionController #:nodoc:
diff --git a/actionpack/lib/action_controller/metal/parameter_encoding.rb b/actionpack/lib/action_controller/metal/parameter_encoding.rb
index ecc691619e..7a45732d31 100644
--- a/actionpack/lib/action_controller/metal/parameter_encoding.rb
+++ b/actionpack/lib/action_controller/metal/parameter_encoding.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # Specify binary encoding for parameters for a given action.
   module ParameterEncoding
diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
index 818af549eb..f4f2381286 100644
--- a/actionpack/lib/action_controller/metal/params_wrapper.rb
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/slice"
 require "active_support/core_ext/hash/except"
 require "active_support/core_ext/module/anonymous"
diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
index fdfe82f96b..2db2c78622 100644
--- a/actionpack/lib/action_controller/metal/redirecting.rb
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module Redirecting
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index 23c21b0501..26752571f8 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "set"
 
 module ActionController
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index 67f207afc2..d32eabf9ba 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/string/filters"
 
 module ActionController
diff --git a/actionpack/lib/action_controller/metal/request_forgery_protection.rb b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
index 027dae60fa..d397c62461 100644
--- a/actionpack/lib/action_controller/metal/request_forgery_protection.rb
+++ b/actionpack/lib/action_controller/metal/request_forgery_protection.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/session/abstract/id"
 require_relative "exceptions"
 require "active_support/security_utils"
diff --git a/actionpack/lib/action_controller/metal/rescue.rb b/actionpack/lib/action_controller/metal/rescue.rb
index 25757938f5..843c99f57b 100644
--- a/actionpack/lib/action_controller/metal/rescue.rb
+++ b/actionpack/lib/action_controller/metal/rescue.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController #:nodoc:
   # This module is responsible for providing `rescue_from` helpers
   # to controllers and configuring when detailed exceptions must be
diff --git a/actionpack/lib/action_controller/metal/streaming.rb b/actionpack/lib/action_controller/metal/streaming.rb
index 58cf60ad2a..0b1598bf1b 100644
--- a/actionpack/lib/action_controller/metal/streaming.rb
+++ b/actionpack/lib/action_controller/metal/streaming.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/chunked"
 
 module ActionController #:nodoc:
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
index ef61485a70..ef7c4c4c16 100644
--- a/actionpack/lib/action_controller/metal/strong_parameters.rb
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/indifferent_access"
 require "active_support/core_ext/hash/transform_values"
 require "active_support/core_ext/array/wrap"
diff --git a/actionpack/lib/action_controller/metal/testing.rb b/actionpack/lib/action_controller/metal/testing.rb
index 9bb416178a..b07f1f3d8c 100644
--- a/actionpack/lib/action_controller/metal/testing.rb
+++ b/actionpack/lib/action_controller/metal/testing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module Testing
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/metal/url_for.rb b/actionpack/lib/action_controller/metal/url_for.rb
index 21ed5b4ec8..84dbb59a63 100644
--- a/actionpack/lib/action_controller/metal/url_for.rb
+++ b/actionpack/lib/action_controller/metal/url_for.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   # Includes +url_for+ into the host class. The class has to provide a +RouteSet+ by implementing
   # the <tt>_routes</tt> method. Otherwise, an exception will be raised.
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
index 1c1cd58732..7dea22931c 100644
--- a/actionpack/lib/action_controller/railtie.rb
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rails"
 require "action_controller"
 require "action_dispatch/railtie"
diff --git a/actionpack/lib/action_controller/railties/helpers.rb b/actionpack/lib/action_controller/railties/helpers.rb
index 3985c6b273..fa746fa9e8 100644
--- a/actionpack/lib/action_controller/railties/helpers.rb
+++ b/actionpack/lib/action_controller/railties/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module Railties
     module Helpers
diff --git a/actionpack/lib/action_controller/renderer.rb b/actionpack/lib/action_controller/renderer.rb
index cbb719d8b2..49c5b782f0 100644
--- a/actionpack/lib/action_controller/renderer.rb
+++ b/actionpack/lib/action_controller/renderer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/keys"
 
 module ActionController
diff --git a/actionpack/lib/action_controller/template_assertions.rb b/actionpack/lib/action_controller/template_assertions.rb
index 0179f4afcd..dd83c1a283 100644
--- a/actionpack/lib/action_controller/template_assertions.rb
+++ b/actionpack/lib/action_controller/template_assertions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionController
   module TemplateAssertions
     def assert_template(options = {}, message = nil)
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index 9d8240e46d..50a96bce98 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/session/abstract/id"
 require "active_support/core_ext/hash/conversions"
 require "active_support/core_ext/object/to_query"
diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
index 303790e96d..34937f3229 100644
--- a/actionpack/lib/action_dispatch.rb
+++ b/actionpack/lib/action_dispatch.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #--
 # Copyright (c) 2004-2017 David Heinemeier Hansson
 #
diff --git a/actionpack/lib/action_dispatch/http/cache.rb b/actionpack/lib/action_dispatch/http/cache.rb
index 985e0fb972..2cc609406a 100644
--- a/actionpack/lib/action_dispatch/http/cache.rb
+++ b/actionpack/lib/action_dispatch/http/cache.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Http
     module Cache
diff --git a/actionpack/lib/action_dispatch/http/filter_parameters.rb b/actionpack/lib/action_dispatch/http/filter_parameters.rb
index eb6761d067..b7141cc1b9 100644
--- a/actionpack/lib/action_dispatch/http/filter_parameters.rb
+++ b/actionpack/lib/action_dispatch/http/filter_parameters.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "parameter_filter"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/http/filter_redirect.rb b/actionpack/lib/action_dispatch/http/filter_redirect.rb
index fc3c44582a..25394fe5dd 100644
--- a/actionpack/lib/action_dispatch/http/filter_redirect.rb
+++ b/actionpack/lib/action_dispatch/http/filter_redirect.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Http
     module FilterRedirect
diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
index 3c03976f03..c3c2a9d8c5 100644
--- a/actionpack/lib/action_dispatch/http/headers.rb
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Http
     # Provides access to the request's HTTP headers from the environment.
diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index 5994a01c78..0ca18d98a1 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/module/attribute_accessors"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index 5a0f661d99..d797e90e52 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # -*- frozen-string-literal: true -*-
 
 require "singleton"
diff --git a/actionpack/lib/action_dispatch/http/mime_types.rb b/actionpack/lib/action_dispatch/http/mime_types.rb
index 8b04174f1f..5d866e5d71 100644
--- a/actionpack/lib/action_dispatch/http/mime_types.rb
+++ b/actionpack/lib/action_dispatch/http/mime_types.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Build list of Mime types for HTTP responses
 # http://www.iana.org/assignments/media-types/
 
diff --git a/actionpack/lib/action_dispatch/http/parameter_filter.rb b/actionpack/lib/action_dispatch/http/parameter_filter.rb
index 1d2b4b902b..1d58964862 100644
--- a/actionpack/lib/action_dispatch/http/parameter_filter.rb
+++ b/actionpack/lib/action_dispatch/http/parameter_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/object/duplicable"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/http/parameters.rb b/actionpack/lib/action_dispatch/http/parameters.rb
index 7c585dbe68..d80d1d714c 100644
--- a/actionpack/lib/action_dispatch/http/parameters.rb
+++ b/actionpack/lib/action_dispatch/http/parameters.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Http
     module Parameters
diff --git a/actionpack/lib/action_dispatch/http/rack_cache.rb b/actionpack/lib/action_dispatch/http/rack_cache.rb
index 003ae4029d..3e2d01aea3 100644
--- a/actionpack/lib/action_dispatch/http/rack_cache.rb
+++ b/actionpack/lib/action_dispatch/http/rack_cache.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/cache"
 require "rack/cache/context"
 require "active_support/cache"
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 29d8ba3d04..84b2ef253d 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/module/attribute_accessors"
 require_relative "filter_redirect"
 require_relative "cache"
diff --git a/actionpack/lib/action_dispatch/http/upload.rb b/actionpack/lib/action_dispatch/http/upload.rb
index 225272d66e..0b162dc7f1 100644
--- a/actionpack/lib/action_dispatch/http/upload.rb
+++ b/actionpack/lib/action_dispatch/http/upload.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Http
     # Models uploaded files.
diff --git a/actionpack/lib/action_dispatch/journey.rb b/actionpack/lib/action_dispatch/journey.rb
index 222cbf4584..903063d00f 100644
--- a/actionpack/lib/action_dispatch/journey.rb
+++ b/actionpack/lib/action_dispatch/journey.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "journey/router"
 require_relative "journey/gtg/builder"
 require_relative "journey/gtg/simulator"
diff --git a/actionpack/lib/action_dispatch/journey/gtg/builder.rb b/actionpack/lib/action_dispatch/journey/gtg/builder.rb
index b1132ef17c..7e3d957baa 100644
--- a/actionpack/lib/action_dispatch/journey/gtg/builder.rb
+++ b/actionpack/lib/action_dispatch/journey/gtg/builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "transition_table"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/gtg/simulator.rb b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
index 62f052ced6..2ee4f5c30c 100644
--- a/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
+++ b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "strscan"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
index 278e4f0e11..6ed478f816 100644
--- a/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
+++ b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "../nfa/dot"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/nfa/builder.rb b/actionpack/lib/action_dispatch/journey/nfa/builder.rb
index 5b628d8cef..3135c05ffa 100644
--- a/actionpack/lib/action_dispatch/journey/nfa/builder.rb
+++ b/actionpack/lib/action_dispatch/journey/nfa/builder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "transition_table"
 require_relative "../gtg/transition_table"
 
diff --git a/actionpack/lib/action_dispatch/journey/nfa/dot.rb b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
index 8119e5d9da..bdb78d8d48 100644
--- a/actionpack/lib/action_dispatch/journey/nfa/dot.rb
+++ b/actionpack/lib/action_dispatch/journey/nfa/dot.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Journey # :nodoc:
     module NFA # :nodoc:
diff --git a/actionpack/lib/action_dispatch/journey/nfa/simulator.rb b/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
index 324d0eed15..8efe48d91c 100644
--- a/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
+++ b/actionpack/lib/action_dispatch/journey/nfa/simulator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "strscan"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb b/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
index d18243545b..bfd929357b 100644
--- a/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
+++ b/actionpack/lib/action_dispatch/journey/nfa/transition_table.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "dot"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/nodes/node.rb b/actionpack/lib/action_dispatch/journey/nodes/node.rb
index 97acad6995..0a84f28c1a 100644
--- a/actionpack/lib/action_dispatch/journey/nodes/node.rb
+++ b/actionpack/lib/action_dispatch/journey/nodes/node.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "../visitors"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/journey/parser_extras.rb b/actionpack/lib/action_dispatch/journey/parser_extras.rb
index d26f0e121f..dfbc6c4529 100644
--- a/actionpack/lib/action_dispatch/journey/parser_extras.rb
+++ b/actionpack/lib/action_dispatch/journey/parser_extras.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "scanner"
 require_relative "nodes/node"
 
diff --git a/actionpack/lib/action_dispatch/journey/path/pattern.rb b/actionpack/lib/action_dispatch/journey/path/pattern.rb
index cf0108ec32..2d85a89a56 100644
--- a/actionpack/lib/action_dispatch/journey/path/pattern.rb
+++ b/actionpack/lib/action_dispatch/journey/path/pattern.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Journey # :nodoc:
     module Path # :nodoc:
diff --git a/actionpack/lib/action_dispatch/journey/route.rb b/actionpack/lib/action_dispatch/journey/route.rb
index 0acbac1d9d..8165709a3d 100644
--- a/actionpack/lib/action_dispatch/journey/route.rb
+++ b/actionpack/lib/action_dispatch/journey/route.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # :stopdoc:
   module Journey
diff --git a/actionpack/lib/action_dispatch/journey/router.rb b/actionpack/lib/action_dispatch/journey/router.rb
index 85f4aade55..809bfcbe8a 100644
--- a/actionpack/lib/action_dispatch/journey/router.rb
+++ b/actionpack/lib/action_dispatch/journey/router.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "router/utils"
 require_relative "routes"
 require_relative "formatter"
diff --git a/actionpack/lib/action_dispatch/journey/router/utils.rb b/actionpack/lib/action_dispatch/journey/router/utils.rb
index 3336036a03..35df7f1aae 100644
--- a/actionpack/lib/action_dispatch/journey/router/utils.rb
+++ b/actionpack/lib/action_dispatch/journey/router/utils.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Journey # :nodoc:
     class Router # :nodoc:
@@ -13,7 +15,7 @@ module ActionDispatch
         #   normalize_path("")      # => "/"
         #   normalize_path("/%ab")  # => "/%AB"
         def self.normalize_path(path)
-          path ||= ''
+          path ||= ""
           encoding = path.encoding
           path = "/#{path}".dup
           path.squeeze!("/".freeze)
diff --git a/actionpack/lib/action_dispatch/journey/routes.rb b/actionpack/lib/action_dispatch/journey/routes.rb
index f7b009109e..639c063495 100644
--- a/actionpack/lib/action_dispatch/journey/routes.rb
+++ b/actionpack/lib/action_dispatch/journey/routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Journey # :nodoc:
     # The Routing table. Contains all routes for a system. Routes can be
diff --git a/actionpack/lib/action_dispatch/middleware/callbacks.rb b/actionpack/lib/action_dispatch/middleware/callbacks.rb
index ff129cf96a..5b2ad36dd5 100644
--- a/actionpack/lib/action_dispatch/middleware/callbacks.rb
+++ b/actionpack/lib/action_dispatch/middleware/callbacks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # Provides callbacks to be executed before and after dispatching the request.
   class Callbacks
diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index 533925ebe1..5a55ee13ee 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/keys"
 require "active_support/key_generator"
 require "active_support/message_verifier"
diff --git a/actionpack/lib/action_dispatch/middleware/debug_locks.rb b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
index 74b952528e..c61a941010 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_locks.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # This middleware can be used to diagnose deadlocks in the autoload interlock.
   #
diff --git a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
index 08b4541d24..4f69abfa6f 100644
--- a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
+++ b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/module/attribute_accessors"
 require "rack/utils"
 
diff --git a/actionpack/lib/action_dispatch/middleware/executor.rb b/actionpack/lib/action_dispatch/middleware/executor.rb
index 3d43f97a2b..129b18d3d9 100644
--- a/actionpack/lib/action_dispatch/middleware/executor.rb
+++ b/actionpack/lib/action_dispatch/middleware/executor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/body_proxy"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/middleware/flash.rb b/actionpack/lib/action_dispatch/middleware/flash.rb
index 6b29ce63ba..3e11846778 100644
--- a/actionpack/lib/action_dispatch/middleware/flash.rb
+++ b/actionpack/lib/action_dispatch/middleware/flash.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/keys"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
index 46f0f675b9..02be97b4cc 100644
--- a/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/public_exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # When called, this middleware renders an error page. By default if an HTML
   # response is expected it will render static error pages from the `/public`
diff --git a/actionpack/lib/action_dispatch/middleware/reloader.rb b/actionpack/lib/action_dispatch/middleware/reloader.rb
index 6d64b1424b..8bb3ba7504 100644
--- a/actionpack/lib/action_dispatch/middleware/reloader.rb
+++ b/actionpack/lib/action_dispatch/middleware/reloader.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # ActionDispatch::Reloader wraps the request with callbacks provided by ActiveSupport::Reloader
   # callbacks, intended to assist with code reloading during development.
diff --git a/actionpack/lib/action_dispatch/middleware/remote_ip.rb b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
index 53d5a4918c..7ccb99c7f0 100644
--- a/actionpack/lib/action_dispatch/middleware/remote_ip.rb
+++ b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "ipaddr"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/middleware/request_id.rb b/actionpack/lib/action_dispatch/middleware/request_id.rb
index 1925ffd9dd..805d3f2148 100644
--- a/actionpack/lib/action_dispatch/middleware/request_id.rb
+++ b/actionpack/lib/action_dispatch/middleware/request_id.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "securerandom"
 require "active_support/core_ext/string/access"
 
diff --git a/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb b/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb
index 31979fa576..e054fefc9b 100644
--- a/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb
+++ b/actionpack/lib/action_dispatch/middleware/session/abstract_store.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/utils"
 require "rack/request"
 require "rack/session/abstract/id"
diff --git a/actionpack/lib/action_dispatch/middleware/session/cache_store.rb b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
index 4babeb6354..c84bc8bfad 100644
--- a/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
+++ b/actionpack/lib/action_dispatch/middleware/session/cache_store.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "abstract_store"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
index 496f221617..65e93984e3 100644
--- a/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
+++ b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/keys"
 require_relative "abstract_store"
 require "rack/session/cookie"
diff --git a/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb b/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb
index bc2b1c9b12..f0aec39c9c 100644
--- a/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb
+++ b/actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "abstract_store"
 begin
   require "rack/session/dalli"
diff --git a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
index db84ff48e9..d2e739d27f 100644
--- a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "../http/request"
 require_relative "exception_wrapper"
 
diff --git a/actionpack/lib/action_dispatch/middleware/stack.rb b/actionpack/lib/action_dispatch/middleware/stack.rb
index 6949b31e75..b82f8aa3a3 100644
--- a/actionpack/lib/action_dispatch/middleware/stack.rb
+++ b/actionpack/lib/action_dispatch/middleware/stack.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/inflector/methods"
 require "active_support/dependencies"
 
diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index 7662e164b8..4743a7ce61 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_dispatch"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
index 3547a8604f..d86d0b10c2 100644
--- a/actionpack/lib/action_dispatch/request/session.rb
+++ b/actionpack/lib/action_dispatch/request/session.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/session/abstract/id"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/request/utils.rb b/actionpack/lib/action_dispatch/request/utils.rb
index daac68d4b4..0ae464082d 100644
--- a/actionpack/lib/action_dispatch/request/utils.rb
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   class Request
     class Utils # :nodoc:
diff --git a/actionpack/lib/action_dispatch/routing.rb b/actionpack/lib/action_dispatch/routing.rb
index 87dd1eba38..72f7407c6e 100644
--- a/actionpack/lib/action_dispatch/routing.rb
+++ b/actionpack/lib/action_dispatch/routing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/string/filters"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/routing/endpoint.rb b/actionpack/lib/action_dispatch/routing/endpoint.rb
index 88aa13c3e8..e911b6537b 100644
--- a/actionpack/lib/action_dispatch/routing/endpoint.rb
+++ b/actionpack/lib/action_dispatch/routing/endpoint.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Routing
     class Endpoint # :nodoc:
diff --git a/actionpack/lib/action_dispatch/routing/inspector.rb b/actionpack/lib/action_dispatch/routing/inspector.rb
index 9aa4b92df2..b2868b7427 100644
--- a/actionpack/lib/action_dispatch/routing/inspector.rb
+++ b/actionpack/lib/action_dispatch/routing/inspector.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "delegate"
 require "active_support/core_ext/string/strip"
 
diff --git a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
index e89ea8b21d..6da869c0c2 100644
--- a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
+++ b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Routing
     # Polymorphic URL helpers are methods for smart resolution to a named route call when
diff --git a/actionpack/lib/action_dispatch/routing/redirection.rb b/actionpack/lib/action_dispatch/routing/redirection.rb
index 6396b5031d..a04f06de1b 100644
--- a/actionpack/lib/action_dispatch/routing/redirection.rb
+++ b/actionpack/lib/action_dispatch/routing/redirection.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "../http/request"
 require "active_support/core_ext/uri"
 require "active_support/core_ext/array/extract_options"
diff --git a/actionpack/lib/action_dispatch/routing/routes_proxy.rb b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
index af0de7366b..587a72729c 100644
--- a/actionpack/lib/action_dispatch/routing/routes_proxy.rb
+++ b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/extract_options"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index a9bdefa775..6f3db258ab 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Routing
     # In <tt>config/routes.rb</tt> you define URL-to-controller mappings, but the reverse
diff --git a/actionpack/lib/action_dispatch/system_test_case.rb b/actionpack/lib/action_dispatch/system_test_case.rb
index 23ce8d5a92..ae4aeac59d 100644
--- a/actionpack/lib/action_dispatch/system_test_case.rb
+++ b/actionpack/lib/action_dispatch/system_test_case.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "capybara/dsl"
 require "capybara/minitest"
 require "action_controller"
diff --git a/actionpack/lib/action_dispatch/system_testing/driver.rb b/actionpack/lib/action_dispatch/system_testing/driver.rb
index 81e6f0fc80..4279336f2f 100644
--- a/actionpack/lib/action_dispatch/system_testing/driver.rb
+++ b/actionpack/lib/action_dispatch/system_testing/driver.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module SystemTesting
     class Driver # :nodoc:
diff --git a/actionpack/lib/action_dispatch/system_testing/server.rb b/actionpack/lib/action_dispatch/system_testing/server.rb
index 89ca6944d9..76bada8df1 100644
--- a/actionpack/lib/action_dispatch/system_testing/server.rb
+++ b/actionpack/lib/action_dispatch/system_testing/server.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rack/handler/puma"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
index 859d68e475..4eef15b6c2 100644
--- a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module SystemTesting
     module TestHelpers
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
index f03f0d4299..ffa85f4e14 100644
--- a/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module SystemTesting
     module TestHelpers
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb
index 2d3f4662d7..ef680cafed 100644
--- a/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/undef_methods.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module SystemTesting
     module TestHelpers
diff --git a/actionpack/lib/action_dispatch/testing/assertion_response.rb b/actionpack/lib/action_dispatch/testing/assertion_response.rb
index c37726957e..dc019db6ac 100644
--- a/actionpack/lib/action_dispatch/testing/assertion_response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertion_response.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   # This is a class that abstracts away an asserted response. It purposely
   # does not inherit from Response because it doesn't need it. That means it
diff --git a/actionpack/lib/action_dispatch/testing/assertions.rb b/actionpack/lib/action_dispatch/testing/assertions.rb
index 4ea18d671d..08c2969685 100644
--- a/actionpack/lib/action_dispatch/testing/assertions.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rails-dom-testing"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index 749f2eab57..98b1965d22 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   module Assertions
     # A small suite of assertions that test responses from \Rails applications.
diff --git a/actionpack/lib/action_dispatch/testing/assertions/routing.rb b/actionpack/lib/action_dispatch/testing/assertions/routing.rb
index 8645df4370..5390581139 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/routing.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/routing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "uri"
 require "active_support/core_ext/hash/indifferent_access"
 require "active_support/core_ext/string/access"
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index beba4e3c36..ae1f368e8b 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "stringio"
 require "uri"
 require "active_support/core_ext/kernel/singleton_class"
diff --git a/actionpack/lib/action_dispatch/testing/request_encoder.rb b/actionpack/lib/action_dispatch/testing/request_encoder.rb
index 8c27e9ecb7..01246b7a2e 100644
--- a/actionpack/lib/action_dispatch/testing/request_encoder.rb
+++ b/actionpack/lib/action_dispatch/testing/request_encoder.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionDispatch
   class RequestEncoder # :nodoc:
     class IdentityEncoder
diff --git a/actionpack/lib/action_dispatch/testing/test_process.rb b/actionpack/lib/action_dispatch/testing/test_process.rb
index 8061ac2e3b..3b63706aaa 100644
--- a/actionpack/lib/action_dispatch/testing/test_process.rb
+++ b/actionpack/lib/action_dispatch/testing/test_process.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "../middleware/cookies"
 require_relative "../middleware/flash"
 
diff --git a/actionpack/lib/action_dispatch/testing/test_request.rb b/actionpack/lib/action_dispatch/testing/test_request.rb
index ec949c869b..0a4dec1364 100644
--- a/actionpack/lib/action_dispatch/testing/test_request.rb
+++ b/actionpack/lib/action_dispatch/testing/test_request.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/indifferent_access"
 require "rack/utils"
 
diff --git a/actionpack/lib/action_dispatch/testing/test_response.rb b/actionpack/lib/action_dispatch/testing/test_response.rb
index 2a1a9ffce9..0b7e9ca945 100644
--- a/actionpack/lib/action_dispatch/testing/test_response.rb
+++ b/actionpack/lib/action_dispatch/testing/test_response.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "request_encoder"
 
 module ActionDispatch
diff --git a/actionpack/lib/action_pack.rb b/actionpack/lib/action_pack.rb
index 6a74baff09..fe2fc7c474 100644
--- a/actionpack/lib/action_pack.rb
+++ b/actionpack/lib/action_pack.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #--
 # Copyright (c) 2004-2017 David Heinemeier Hansson
 #
diff --git a/actionpack/lib/action_pack/gem_version.rb b/actionpack/lib/action_pack/gem_version.rb
index fddc3033d5..28bc153f4d 100644
--- a/actionpack/lib/action_pack/gem_version.rb
+++ b/actionpack/lib/action_pack/gem_version.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActionPack
   # Returns the version of the currently loaded Action Pack as a <tt>Gem::Version</tt>
   def self.gem_version
diff --git a/actionpack/lib/action_pack/version.rb b/actionpack/lib/action_pack/version.rb
index 3d96158431..fd039fe140 100644
--- a/actionpack/lib/action_pack/version.rb
+++ b/actionpack/lib/action_pack/version.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "gem_version"
 
 module ActionPack