Merge branch 'master' into bug/filtered_parameters_class

32 files changed, 199 insertions, 101 deletions

diff --git a/actionpack/lib/abstract_controller/base.rb b/actionpack/lib/abstract_controller/base.rb
index e7cb6347a2..dc79820a82 100644
--- a/actionpack/lib/abstract_controller/base.rb
+++ b/actionpack/lib/abstract_controller/base.rb
@@ -14,8 +14,16 @@ module AbstractController
   # expected to provide their own +render+ method, since rendering means
   # different things depending on the context.
   class Base
+    ##
+    # Returns the body of the HTTP response sent by the controller.
     attr_internal :response_body
+
+    ##
+    # Returns the name of the action this controller is processing.
     attr_internal :action_name
+
+    ##
+    # Returns the formats that can be processed by the controller.
     attr_internal :formats
 
     include ActiveSupport::Configurable
diff --git a/actionpack/lib/abstract_controller/caching.rb b/actionpack/lib/abstract_controller/caching.rb
index 26e3f08bc1..30e3d4426c 100644
--- a/actionpack/lib/abstract_controller/caching.rb
+++ b/actionpack/lib/abstract_controller/caching.rb
@@ -37,8 +37,7 @@ module AbstractController
       config_accessor :enable_fragment_cache_logging
       self.enable_fragment_cache_logging = false
 
-      class_attribute :_view_cache_dependencies
-      self._view_cache_dependencies = []
+      class_attribute :_view_cache_dependencies, default: []
       helper_method :view_cache_dependencies if respond_to?(:helper_method)
     end
 
diff --git a/actionpack/lib/abstract_controller/caching/fragments.rb b/actionpack/lib/abstract_controller/caching/fragments.rb
index c85b4adba1..14e4a82523 100644
--- a/actionpack/lib/abstract_controller/caching/fragments.rb
+++ b/actionpack/lib/abstract_controller/caching/fragments.rb
@@ -25,7 +25,10 @@ module AbstractController
 
         self.fragment_cache_keys = []
 
-        helper_method :fragment_cache_key if respond_to?(:helper_method)
+        if respond_to?(:helper_method)
+          helper_method :fragment_cache_key
+          helper_method :combined_fragment_cache_key
+        end
       end
 
       module ClassMethods
@@ -62,17 +65,36 @@ module AbstractController
       # with the specified +key+ value. The key is expanded using
       # ActiveSupport::Cache.expand_cache_key.
       def fragment_cache_key(key)
+        ActiveSupport::Deprecation.warn(<<-MSG.squish)
+          Calling fragment_cache_key directly is deprecated and will be removed in Rails 6.0.
+          All fragment accessors now use the combined_fragment_cache_key method that retains the key as an array,
+          such that the caching stores can interrogate the parts for cache versions used in
+          recyclable cache keys.
+        MSG
+
         head = self.class.fragment_cache_keys.map { |k| instance_exec(&k) }
         tail = key.is_a?(Hash) ? url_for(key).split("://").last : key
         ActiveSupport::Cache.expand_cache_key([*head, *tail], :views)
       end
 
+      # Given a key (as described in +expire_fragment+), returns
+      # a key array suitable for use in reading, writing, or expiring a
+      # cached fragment. All keys begin with <tt>:views</tt>,
+      # followed by ENV["RAILS_CACHE_ID"] or ENV["RAILS_APP_VERSION"] if set,
+      # followed by any controller-wide key prefix values, ending
+      # with the specified +key+ value.
+      def combined_fragment_cache_key(key)
+        head = self.class.fragment_cache_keys.map { |k| instance_exec(&k) }
+        tail = key.is_a?(Hash) ? url_for(key).split("://").last : key
+        [ :views, (ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]), *head, *tail ].compact
+      end
+
       # Writes +content+ to the location signified by
       # +key+ (see +expire_fragment+ for acceptable formats).
       def write_fragment(key, content, options = nil)
         return content unless cache_configured?
 
-        key = fragment_cache_key(key)
+        key = combined_fragment_cache_key(key)
         instrument_fragment_cache :write_fragment, key do
           content = content.to_str
           cache_store.write(key, content, options)
@@ -85,7 +107,7 @@ module AbstractController
       def read_fragment(key, options = nil)
         return unless cache_configured?
 
-        key = fragment_cache_key(key)
+        key = combined_fragment_cache_key(key)
         instrument_fragment_cache :read_fragment, key do
           result = cache_store.read(key, options)
           result.respond_to?(:html_safe) ? result.html_safe : result
@@ -96,7 +118,7 @@ module AbstractController
       # +key+ exists (see +expire_fragment+ for acceptable formats).
       def fragment_exist?(key, options = nil)
         return unless cache_configured?
-        key = fragment_cache_key(key)
+        key = combined_fragment_cache_key(key)
 
         instrument_fragment_cache :exist_fragment?, key do
           cache_store.exist?(key, options)
@@ -123,7 +145,7 @@ module AbstractController
       # method (or <tt>delete_matched</tt>, for Regexp keys).
       def expire_fragment(key, options = nil)
         return unless cache_configured?
-        key = fragment_cache_key(key) unless key.is_a?(Regexp)
+        key = combined_fragment_cache_key(key) unless key.is_a?(Regexp)
 
         instrument_fragment_cache :expire_fragment, key do
           if key.is_a?(Regexp)
@@ -135,8 +157,7 @@ module AbstractController
       end
 
       def instrument_fragment_cache(name, key) # :nodoc:
-        payload = instrument_payload(key)
-        ActiveSupport::Notifications.instrument("#{name}.#{instrument_name}", payload) { yield }
+        ActiveSupport::Notifications.instrument("#{name}.#{instrument_name}", instrument_payload(key)) { yield }
       end
     end
   end
diff --git a/actionpack/lib/abstract_controller/callbacks.rb b/actionpack/lib/abstract_controller/callbacks.rb
index ce4ecf17cc..ba7dec6083 100644
--- a/actionpack/lib/abstract_controller/callbacks.rb
+++ b/actionpack/lib/abstract_controller/callbacks.rb
@@ -1,4 +1,24 @@
 module AbstractController
+  # = Abstract Controller Callbacks
+  #
+  # Abstract Controller provides hooks during the life cycle of a controller action.
+  # Callbacks allow you to trigger logic during this cycle. Available callbacks are:
+  #
+  # * <tt>after_action</tt>
+  # * <tt>append_after_action</tt>
+  # * <tt>append_around_action</tt>
+  # * <tt>append_before_action</tt>
+  # * <tt>around_action</tt>
+  # * <tt>before_action</tt>
+  # * <tt>prepend_after_action</tt>
+  # * <tt>prepend_around_action</tt>
+  # * <tt>prepend_before_action</tt>
+  # * <tt>skip_after_action</tt>
+  # * <tt>skip_around_action</tt>
+  # * <tt>skip_before_action</tt>
+  #
+  # NOTE: Calling the same callback multiple times will overwrite previous callback definitions.
+  #
   module Callbacks
     extend ActiveSupport::Concern
 
diff --git a/actionpack/lib/abstract_controller/helpers.rb b/actionpack/lib/abstract_controller/helpers.rb
index ef3be7af83..2e50637c39 100644
--- a/actionpack/lib/abstract_controller/helpers.rb
+++ b/actionpack/lib/abstract_controller/helpers.rb
@@ -5,11 +5,8 @@ module AbstractController
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :_helpers
-      self._helpers = Module.new
-
-      class_attribute :_helper_methods
-      self._helper_methods = Array.new
+      class_attribute :_helpers, default: Module.new
+      class_attribute :_helper_methods, default: Array.new
     end
 
     class MissingHelperError < LoadError
diff --git a/actionpack/lib/abstract_controller/translation.rb b/actionpack/lib/abstract_controller/translation.rb
index 9e3858802a..e4ac95df50 100644
--- a/actionpack/lib/abstract_controller/translation.rb
+++ b/actionpack/lib/abstract_controller/translation.rb
@@ -13,7 +13,7 @@ module AbstractController
         path = controller_path.tr("/", ".")
         defaults = [:"#{path}#{key}"]
         defaults << options[:default] if options[:default]
-        options[:default] = defaults
+        options[:default] = defaults.flatten
         key = "#{path}.#{action_name}#{key}"
       end
       I18n.translate(key, options)
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index d29a5fe68f..d00fcbcd13 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -60,9 +60,9 @@ module ActionController
       class_eval <<-METHOD, __FILE__, __LINE__ + 1
         def #{method}(event)
           return unless logger.info? && ActionController::Base.enable_fragment_cache_logging
-          key_or_path = event.payload[:key] || event.payload[:path]
+          key         = ActiveSupport::Cache.expand_cache_key(event.payload[:key] || event.payload[:path])
           human_name  = #{method.to_s.humanize.inspect}
-          info("\#{human_name} \#{key_or_path} (\#{event.duration.round(1)}ms)")
+          info("\#{human_name} \#{key} (\#{event.duration.round(1)}ms)")
         end
       METHOD
     end
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 246644dcbd..96c708f45a 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -208,8 +208,7 @@ module ActionController
       @_request.reset_session
     end
 
-    class_attribute :middleware_stack
-    self.middleware_stack = ActionController::MiddlewareStack.new
+    class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new
 
     def self.inherited(base) # :nodoc:
       base.middleware_stack = middleware_stack.dup
diff --git a/actionpack/lib/action_controller/metal/conditional_get.rb b/actionpack/lib/action_controller/metal/conditional_get.rb
index eb636fa3f6..0525252c7c 100644
--- a/actionpack/lib/action_controller/metal/conditional_get.rb
+++ b/actionpack/lib/action_controller/metal/conditional_get.rb
@@ -7,8 +7,7 @@ module ActionController
     include Head
 
     included do
-      class_attribute :etaggers
-      self.etaggers = []
+      class_attribute :etaggers, default: []
     end
 
     module ClassMethods
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 798564db96..69c3979a0e 100644
--- a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
+++ b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
@@ -22,8 +22,7 @@ module ActionController
     include ActionController::ConditionalGet
 
     included do
-      class_attribute :etag_with_template_digest
-      self.etag_with_template_digest = true
+      class_attribute :etag_with_template_digest, default: true
 
       ActiveSupport.on_load :action_view, yield: true do
         etag do |options|
diff --git a/actionpack/lib/action_controller/metal/flash.rb b/actionpack/lib/action_controller/metal/flash.rb
index 347fbf0e74..24d1097ebe 100644
--- a/actionpack/lib/action_controller/metal/flash.rb
+++ b/actionpack/lib/action_controller/metal/flash.rb
@@ -3,8 +3,7 @@ module ActionController #:nodoc:
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :_flash_types, instance_accessor: false
-      self._flash_types = []
+      class_attribute :_flash_types, instance_accessor: false, default: []
 
       delegate :flash, to: :request
       add_flash_types(:alert, :notice)
diff --git a/actionpack/lib/action_controller/metal/helpers.rb b/actionpack/lib/action_controller/metal/helpers.rb
index 476d081239..913a4b9a04 100644
--- a/actionpack/lib/action_controller/metal/helpers.rb
+++ b/actionpack/lib/action_controller/metal/helpers.rb
@@ -53,9 +53,8 @@ module ActionController
     include AbstractController::Helpers
 
     included do
-      class_attribute :helpers_path, :include_all_helpers
-      self.helpers_path ||= []
-      self.include_all_helpers = true
+      class_attribute :helpers_path, default: []
+      class_attribute :include_all_helpers, default: true
     end
 
     module ClassMethods
diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
index a89fc1678b..68881b8402 100644
--- a/actionpack/lib/action_controller/metal/params_wrapper.rb
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -159,8 +159,7 @@ module ActionController
     end
 
     included do
-      class_attribute :_wrapper_options
-      self._wrapper_options = Options.from_hash(format: [])
+      class_attribute :_wrapper_options, default: Options.from_hash(format: [])
     end
 
     module ClassMethods
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index 733aca195d..23c21b0501 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -26,8 +26,7 @@ module ActionController
     RENDERERS = Set.new
 
     included do
-      class_attribute :_renderers
-      self._renderers = Set.new.freeze
+      class_attribute :_renderers, default: Set.new.freeze
     end
 
     # Used in <tt>ActionController::Base</tt>
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
index 20330b5091..cd99e3125f 100644
--- a/actionpack/lib/action_controller/metal/strong_parameters.rb
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -119,8 +119,7 @@ module ActionController
   #   params[:key]  # => "value"
   #   params["key"] # => "value"
   class Parameters
-    cattr_accessor :permit_all_parameters, instance_accessor: false
-    self.permit_all_parameters = false
+    cattr_accessor :permit_all_parameters, instance_accessor: false, default: false
 
     cattr_accessor :action_on_unpermitted_parameters, instance_accessor: false
 
@@ -205,8 +204,7 @@ module ActionController
     # config. For instance:
     #
     #    config.always_permitted_parameters = %w( controller action format )
-    cattr_accessor :always_permitted_parameters
-    self.always_permitted_parameters = %w( controller action )
+    cattr_accessor :always_permitted_parameters, default: %w( controller action )
 
     # Returns a new instance of <tt>ActionController::Parameters</tt>.
     # Also, sets the +permitted+ attribute to the default value of
diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index 19f89edbc1..5994a01c78 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -6,8 +6,7 @@ module ActionDispatch
       extend ActiveSupport::Concern
 
       included do
-        mattr_accessor :ignore_accept_header
-        self.ignore_accept_header = false
+        mattr_accessor :ignore_accept_header, default: false
       end
 
       # The MIME type of the HTTP request, such as Mime[:xml].
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 2ee52eeb48..3c91677d55 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -81,8 +81,8 @@ module ActionDispatch # :nodoc:
     LOCATION     = "Location".freeze
     NO_CONTENT_CODES = [100, 101, 102, 204, 205, 304]
 
-    cattr_accessor(:default_charset) { "utf-8" }
-    cattr_accessor(:default_headers)
+    cattr_accessor :default_charset, default: "utf-8"
+    cattr_accessor :default_headers
 
     include Rack::Response::Helpers
     # Aliasing these off because AD::Http::Cache::Response defines them.
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index b6be48a48b..f902fe36e0 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -7,8 +7,7 @@ module ActionDispatch
       HOST_REGEXP     = /(^[^:]+:\/\/)?(\[[^\]]+\]|[^:]+)(?::(\d+$))?/
       PROTOCOL_REGEXP = /^([^:]+)(:)?(\/\/)?$/
 
-      mattr_accessor :tld_length
-      self.tld_length = 1
+      mattr_accessor :tld_length, default: 1
 
       class << self
         # Returns the domain part of a host given the domain level.
diff --git a/actionpack/lib/action_dispatch/journey/gtg/simulator.rb b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
index d692f6415c..62f052ced6 100644
--- a/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
+++ b/actionpack/lib/action_dispatch/journey/gtg/simulator.rb
@@ -18,14 +18,6 @@ module ActionDispatch
           @tt = transition_table
         end
 
-        def simulate(string)
-          ms = memos(string) { return }
-          MatchData.new(ms)
-        end
-
-        alias :=~    :simulate
-        alias :match :simulate
-
         def memos(string)
           input = StringScanner.new(string)
           state = [0]
diff --git a/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
index e1ac2c873e..45aff287b1 100644
--- a/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
+++ b/actionpack/lib/action_dispatch/journey/gtg/transition_table.rb
@@ -82,7 +82,7 @@ module ActionDispatch
         end
 
         def visualizer(paths, title = "FSM")
-          viz_dir   = File.join File.dirname(__FILE__), "..", "visualizer"
+          viz_dir   = File.join __dir__, "..", "visualizer"
           fsm_js    = File.read File.join(viz_dir, "fsm.js")
           fsm_css   = File.read File.join(viz_dir, "fsm.css")
           erb       = File.read File.join(viz_dir, "index.html.erb")
diff --git a/actionpack/lib/action_dispatch/journey/route.rb b/actionpack/lib/action_dispatch/journey/route.rb
index 7bc15aa6b3..0acbac1d9d 100644
--- a/actionpack/lib/action_dispatch/journey/route.rb
+++ b/actionpack/lib/action_dispatch/journey/route.rb
@@ -10,11 +10,11 @@ module ActionDispatch
       module VerbMatchers
         VERBS = %w{ DELETE GET HEAD OPTIONS LINK PATCH POST PUT TRACE UNLINK }
         VERBS.each do |v|
-          class_eval <<-eoc
-          class #{v}
-            def self.verb; name.split("::").last; end
-            def self.call(req); req.#{v.downcase}?; end
-          end
+          class_eval <<-eoc, __FILE__, __LINE__ + 1
+            class #{v}
+              def self.verb; name.split("::").last; end
+              def self.call(req); req.#{v.downcase}?; end
+            end
           eoc
         end
 
diff --git a/actionpack/lib/action_dispatch/middleware/cookies.rb b/actionpack/lib/action_dispatch/middleware/cookies.rb
index e565c03a8a..533925ebe1 100644
--- a/actionpack/lib/action_dispatch/middleware/cookies.rb
+++ b/actionpack/lib/action_dispatch/middleware/cookies.rb
@@ -43,6 +43,10 @@ module ActionDispatch
       get_header Cookies::ENCRYPTED_SIGNED_COOKIE_SALT
     end
 
+    def authenticated_encrypted_cookie_salt
+      get_header Cookies::AUTHENTICATED_ENCRYPTED_COOKIE_SALT
+    end
+
     def secret_token
       get_header Cookies::SECRET_TOKEN
     end
@@ -149,6 +153,7 @@ module ActionDispatch
     SIGNED_COOKIE_SALT = "action_dispatch.signed_cookie_salt".freeze
     ENCRYPTED_COOKIE_SALT = "action_dispatch.encrypted_cookie_salt".freeze
     ENCRYPTED_SIGNED_COOKIE_SALT = "action_dispatch.encrypted_signed_cookie_salt".freeze
+    AUTHENTICATED_ENCRYPTED_COOKIE_SALT = "action_dispatch.authenticated_encrypted_cookie_salt".freeze
     SECRET_TOKEN = "action_dispatch.secret_token".freeze
     SECRET_KEY_BASE = "action_dispatch.secret_key_base".freeze
     COOKIES_SERIALIZER = "action_dispatch.cookies_serializer".freeze
@@ -207,6 +212,9 @@ module ActionDispatch
       # If +secrets.secret_key_base+ and +secrets.secret_token+ (deprecated) are both set,
       # legacy cookies signed with the old key generator will be transparently upgraded.
       #
+      # If +config.action_dispatch.encrypted_cookie_salt+ and +config.action_dispatch.encrypted_signed_cookie_salt+
+      # are both set, legacy cookies encrypted with HMAC AES-256-CBC will be transparently upgraded.
+      #
       # This jar requires that you set a suitable secret for the verification on your app's +secrets.secret_key_base+.
       #
       # Example:
@@ -219,6 +227,8 @@ module ActionDispatch
         @encrypted ||=
           if upgrade_legacy_signed_cookies?
             UpgradeLegacyEncryptedCookieJar.new(self)
+          elsif upgrade_legacy_hmac_aes_cbc_cookies?
+            UpgradeLegacyHmacAesCbcCookieJar.new(self)
           else
             EncryptedCookieJar.new(self)
           end
@@ -240,6 +250,13 @@ module ActionDispatch
         def upgrade_legacy_signed_cookies?
           request.secret_token.present? && request.secret_key_base.present?
         end
+
+        def upgrade_legacy_hmac_aes_cbc_cookies?
+          request.secret_key_base.present?                       &&
+            request.authenticated_encrypted_cookie_salt.present? &&
+            request.encrypted_signed_cookie_salt.present?        &&
+            request.encrypted_cookie_salt.present?
+        end
     end
 
     # Passing the ActiveSupport::MessageEncryptor::NullSerializer downstream
@@ -415,8 +432,7 @@ module ActionDispatch
         end
       end
 
-      mattr_accessor :always_write_cookie
-      self.always_write_cookie = false
+      mattr_accessor :always_write_cookie, default: false
 
       private
 
@@ -576,9 +592,11 @@ module ActionDispatch
             "Read the upgrade documentation to learn more about this new config option."
         end
 
-        secret = key_generator.generate_key(request.encrypted_cookie_salt || "")[0, ActiveSupport::MessageEncryptor.key_len]
-        sign_secret = key_generator.generate_key(request.encrypted_signed_cookie_salt || "")
-        @encryptor = ActiveSupport::MessageEncryptor.new(secret, sign_secret, digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+        cipher = "aes-256-gcm"
+        key_len = ActiveSupport::MessageEncryptor.key_len(cipher)
+        secret = key_generator.generate_key(request.authenticated_encrypted_cookie_salt || "")[0, key_len]
+
+        @encryptor = ActiveSupport::MessageEncryptor.new(secret, cipher: cipher, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
       end
 
       private
@@ -603,6 +621,32 @@ module ActionDispatch
       include VerifyAndUpgradeLegacySignedMessage
     end
 
+    # UpgradeLegacyHmacAesCbcCookieJar is used by ActionDispatch::Session::CookieStore
+    # to upgrade cookies encrypted with AES-256-CBC with HMAC to AES-256-GCM
+    class UpgradeLegacyHmacAesCbcCookieJar < EncryptedCookieJar
+      def initialize(parent_jar)
+        super
+
+        secret = key_generator.generate_key(request.encrypted_cookie_salt || "")[0, ActiveSupport::MessageEncryptor.key_len]
+        sign_secret = key_generator.generate_key(request.encrypted_signed_cookie_salt || "")
+
+        @legacy_encryptor = ActiveSupport::MessageEncryptor.new(secret, sign_secret, cipher: "aes-256-cbc", digest: digest, serializer: ActiveSupport::MessageEncryptor::NullSerializer)
+      end
+
+      def decrypt_and_verify_legacy_encrypted_message(name, signed_message)
+        deserialize(name, @legacy_encryptor.decrypt_and_verify(signed_message)).tap do |value|
+          self[name] = { value: value }
+        end
+      rescue ActiveSupport::MessageVerifier::InvalidSignature, ActiveSupport::MessageEncryptor::InvalidMessage
+        nil
+      end
+
+      private
+        def parse(name, signed_message)
+          super || decrypt_and_verify_legacy_encrypted_message(name, signed_message)
+        end
+    end
+
     def initialize(app)
       @app = app
     end
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
index 1c720c5a8e..336a775880 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -10,7 +10,7 @@ module ActionDispatch
   # This middleware is responsible for logging exceptions and
   # showing a debugging page in case the request is local.
   class DebugExceptions
-    RESCUES_TEMPLATE_PATH = File.expand_path("../templates", __FILE__)
+    RESCUES_TEMPLATE_PATH = File.expand_path("templates", __dir__)
 
     class DebugView < ActionView::Base
       def debug_params(params)
diff --git a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
index 397f0a8b92..08b4541d24 100644
--- a/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
+++ b/actionpack/lib/action_dispatch/middleware/exception_wrapper.rb
@@ -3,9 +3,7 @@ require "rack/utils"
 
 module ActionDispatch
   class ExceptionWrapper
-    cattr_accessor :rescue_responses
-    @@rescue_responses = Hash.new(:internal_server_error)
-    @@rescue_responses.merge!(
+    cattr_accessor :rescue_responses, default: Hash.new(:internal_server_error).merge!(
       "ActionController::RoutingError"               => :not_found,
       "AbstractController::ActionNotFound"           => :not_found,
       "ActionController::MethodNotAllowed"           => :method_not_allowed,
@@ -21,9 +19,7 @@ module ActionDispatch
       "Rack::QueryParser::InvalidParameterError"     => :bad_request
     )
 
-    cattr_accessor :rescue_templates
-    @@rescue_templates = Hash.new("diagnostics")
-    @@rescue_templates.merge!(
+    cattr_accessor :rescue_templates, default: Hash.new("diagnostics").merge!(
       "ActionView::MissingTemplate"         => "missing_template",
       "ActionController::RoutingError"      => "routing_error",
       "AbstractController::ActionNotFound"  => "unknown_action",
diff --git a/actionpack/lib/action_dispatch/middleware/static.rb b/actionpack/lib/action_dispatch/middleware/static.rb
index 5d10129d21..fb99f13a1c 100644
--- a/actionpack/lib/action_dispatch/middleware/static.rb
+++ b/actionpack/lib/action_dispatch/middleware/static.rb
@@ -6,11 +6,11 @@ module ActionDispatch
   # When initialized, it can accept optional HTTP headers, which will be set
   # when a response containing a file's contents is delivered.
   #
-  # This middleware will render the file specified in `env["PATH_INFO"]`
+  # This middleware will render the file specified in <tt>env["PATH_INFO"]</tt>
   # where the base path is in the +root+ directory. For example, if the +root+
-  # is set to `public/`, then a request with `env["PATH_INFO"]` of
-  # `assets/application.js` will return a response with the contents of a file
-  # located at `public/assets/application.js` if the file exists. If the file
+  # is set to +public/+, then a request with <tt>env["PATH_INFO"]</tt> of
+  # +assets/application.js+ will return a response with the contents of a file
+  # located at +public/assets/application.js+ if the file exists. If the file
   # does not exist, a 404 "File not Found" response will be returned.
   class FileHandler
     def initialize(root, index: "index", headers: {})
@@ -23,8 +23,8 @@ module ActionDispatch
     # correct read permissions, the return value is a URI-escaped string
     # representing the filename. Otherwise, false is returned.
     #
-    # Used by the `Static` class to check the existence of a valid file
-    # in the server's `public/` directory (see Static#call).
+    # Used by the +Static+ class to check the existence of a valid file
+    # in the server's +public/+ directory (see Static#call).
     def match?(path)
       path = ::Rack::Utils.unescape_path path
       return false unless ::Rack::Utils.valid_path? path
@@ -99,7 +99,7 @@ module ActionDispatch
   # This middleware will attempt to return the contents of a file's body from
   # disk in the response. If a file is not found on disk, the request will be
   # delegated to the application stack. This middleware is commonly initialized
-  # to serve assets from a server's `public/` directory.
+  # to serve assets from a server's +public/+ directory.
   #
   # This middleware verifies the path to ensure that only files
   # living in the root directory can be rendered. A request cannot
diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index 16a18a7f25..7662e164b8 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -16,6 +16,7 @@ module ActionDispatch
     config.action_dispatch.signed_cookie_salt = "signed cookie"
     config.action_dispatch.encrypted_cookie_salt = "encrypted cookie"
     config.action_dispatch.encrypted_signed_cookie_salt = "signed encrypted cookie"
+    config.action_dispatch.use_authenticated_cookie_encryption = false
     config.action_dispatch.perform_deep_munge = true
 
     config.action_dispatch.default_headers = {
@@ -36,6 +37,8 @@ module ActionDispatch
       ActionDispatch::ExceptionWrapper.rescue_responses.merge!(config.action_dispatch.rescue_responses)
       ActionDispatch::ExceptionWrapper.rescue_templates.merge!(config.action_dispatch.rescue_templates)
 
+      config.action_dispatch.authenticated_encrypted_cookie_salt = "authenticated encrypted cookie" if config.action_dispatch.use_authenticated_cookie_encryption
+
       config.action_dispatch.always_write_cookie = Rails.env.development? if config.action_dispatch.always_write_cookie.nil?
       ActionDispatch::Cookies::CookieJar.always_write_cookie = config.action_dispatch.always_write_cookie
 
diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
index 74ba6466cf..3547a8604f 100644
--- a/actionpack/lib/action_dispatch/request/session.rb
+++ b/actionpack/lib/action_dispatch/request/session.rb
@@ -101,11 +101,13 @@ module ActionDispatch
 
       # Returns keys of the session as Array.
       def keys
+        load_for_read!
         @delegate.keys
       end
 
       # Returns values of the session as Array.
       def values
+        load_for_read!
         @delegate.values
       end
 
diff --git a/actionpack/lib/action_dispatch/request/utils.rb b/actionpack/lib/action_dispatch/request/utils.rb
index 3615e4b1d8..4f79c4c21e 100644
--- a/actionpack/lib/action_dispatch/request/utils.rb
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -1,8 +1,7 @@
 module ActionDispatch
   class Request
     class Utils # :nodoc:
-      mattr_accessor :perform_deep_munge
-      self.perform_deep_munge = true
+      mattr_accessor :perform_deep_munge, default: true
 
       def self.each_param_value(params, &block)
         case params
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 74904e3d45..88deee5f5e 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1837,7 +1837,7 @@ module ActionDispatch
             path_types.fetch(String, []).each do |_path|
               route_options = options.dup
               if _path && option_path
-                raise ArgumentError, "Ambigous route definition. Both :path and the route path where specified as strings."
+                raise ArgumentError, "Ambiguous route definition. Both :path and the route path where specified as strings."
               end
               to = get_to_from_path(_path, to, route_options[:action])
               decomposed_match(_path, controller, route_options, _path, to, via, formatted, anchor, options_constraints)
@@ -2038,8 +2038,8 @@ module ActionDispatch
         #     { controller: "pages", action: "index", subdomain: "www" }
         #   end
         #
-        # The return value from the block passed to `direct` must be a valid set of
-        # arguments for `url_for` which will actually build the URL string. This can
+        # The return value from the block passed to +direct+ must be a valid set of
+        # arguments for +url_for+ which will actually build the URL string. This can
         # be one of the following:
         #
         #   * A string, which is treated as a generated URL
@@ -2058,17 +2058,17 @@ module ActionDispatch
         #     [ :products, options.merge(params.permit(:page, :size).to_h.symbolize_keys) ]
         #   end
         #
-        # In this instance the `params` object comes from the context in which the the
+        # In this instance the +params+ object comes from the context in which the the
         # block is executed, e.g. generating a URL inside a controller action or a view.
         # If the block is executed where there isn't a params object such as this:
         #
         #   Rails.application.routes.url_helpers.browse_path
         #
-        # then it will raise a `NameError`. Because of this you need to be aware of the
+        # then it will raise a +NameError+. Because of this you need to be aware of the
         # context in which you will use your custom URL helper when defining it.
         #
-        # NOTE: The `direct` method can't be used inside of a scope block such as
-        # `namespace` or `scope` and will raise an error if it detects that it is.
+        # NOTE: The +direct+ method can't be used inside of a scope block such as
+        # +namespace+ or +scope+ and will raise an error if it detects that it is.
         def direct(name, options = {}, &block)
           unless @scope.root?
             raise RuntimeError, "The direct method can't be used inside a routes scope block"
@@ -2078,8 +2078,8 @@ module ActionDispatch
         end
 
         # Define custom polymorphic mappings of models to URLs. This alters the
-        # behavior of `polymorphic_url` and consequently the behavior of
-        # `link_to` and `form_for` when passed a model instance, e.g:
+        # behavior of +polymorphic_url+ and consequently the behavior of
+        # +link_to+ and +form_for+ when passed a model instance, e.g:
         #
         #   resource :basket
         #
@@ -2087,8 +2087,8 @@ module ActionDispatch
         #     [:basket]
         #   end
         #
-        # This will now generate "/basket" when a `Basket` instance is passed to
-        # `link_to` or `form_for` instead of the standard "/baskets/:id".
+        # This will now generate "/basket" when a +Basket+ instance is passed to
+        # +link_to+ or +form_for+ instead of the standard "/baskets/:id".
         #
         # NOTE: This custom behavior only applies to simple polymorphic URLs where
         # a single model instance is passed and not more complicated forms, e.g:
@@ -2105,7 +2105,7 @@ module ActionDispatch
         #   link_to "Profile", @current_user
         #   link_to "Profile", [:admin, @current_user]
         #
-        # The first `link_to` will generate "/profile" but the second will generate
+        # The first +link_to+ will generate "/profile" but the second will generate
         # the standard polymorphic URL of "/admin/users/1".
         #
         # You can pass options to a polymorphic mapping - the arity for the block
@@ -2116,11 +2116,11 @@ module ActionDispatch
         #   end
         #
         # This generates the URL "/basket#items" because when the last item in an
-        # array passed to `polymorphic_url` is a hash then it's treated as options
+        # array passed to +polymorphic_url+ is a hash then it's treated as options
         # to the URL helper that gets called.
         #
-        # NOTE: The `resolve` method can't be used inside of a scope block such as
-        # `namespace` or `scope` and will raise an error if it detects that it is.
+        # NOTE: The +resolve+ method can't be used inside of a scope block such as
+        # +namespace+ or +scope+ and will raise an error if it detects that it is.
         def resolve(*args, &block)
           unless @scope.root?
             raise RuntimeError, "The resolve method can't be used inside a routes scope block"
diff --git a/actionpack/lib/action_dispatch/system_test_case.rb b/actionpack/lib/action_dispatch/system_test_case.rb
index 98fdb36c91..c39a135ce0 100644
--- a/actionpack/lib/action_dispatch/system_test_case.rb
+++ b/actionpack/lib/action_dispatch/system_test_case.rb
@@ -66,14 +66,18 @@ module ActionDispatch
   #
   # To use a headless driver, like Poltergeist, update your Gemfile to use
   # Poltergeist instead of Selenium and then declare the driver name in the
-  # +application_system_test_case.rb+ file. In this case you would leave out the +:using+
-  # option because the driver is headless.
+  # +application_system_test_case.rb+ file. In this case, you would leave out
+  # the +:using+ option because the driver is headless, but you can still use
+  # +:screen_size+ to change the size of the browser screen, also you can use
+  # +:options+ to pass options supported by the driver. Please refer to your
+  # driver documentation to learn about supported options.
   #
   #   require "test_helper"
   #   require "capybara/poltergeist"
   #
   #   class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
-  #     driven_by :poltergeist
+  #     driven_by :poltergeist, screen_size: [1400, 1400], options:
+  #       { js_errors: true }
   #   end
   #
   # Because <tt>ActionDispatch::SystemTestCase</tt> is a shim between Capybara
diff --git a/actionpack/lib/action_dispatch/system_testing/driver.rb b/actionpack/lib/action_dispatch/system_testing/driver.rb
index 5cf17883f7..1a027f2e23 100644
--- a/actionpack/lib/action_dispatch/system_testing/driver.rb
+++ b/actionpack/lib/action_dispatch/system_testing/driver.rb
@@ -9,23 +9,42 @@ module ActionDispatch
       end
 
       def use
-        register if selenium?
+        register unless rack_test?
+
         setup
       end
 
       private
-        def selenium?
-          @name == :selenium
+        def rack_test?
+          @name == :rack_test
         end
 
         def register
           Capybara.register_driver @name do |app|
-            Capybara::Selenium::Driver.new(app, { browser: @browser }.merge(@options)).tap do |driver|
-              driver.browser.manage.window.size = Selenium::WebDriver::Dimension.new(*@screen_size)
+            case @name
+            when :selenium then register_selenium(app)
+            when :poltergeist then register_poltergeist(app)
+            when :webkit then register_webkit(app)
             end
           end
         end
 
+        def register_selenium(app)
+          Capybara::Selenium::Driver.new(app, { browser: @browser }.merge(@options)).tap do |driver|
+            driver.browser.manage.window.size = Selenium::WebDriver::Dimension.new(*@screen_size)
+          end
+        end
+
+        def register_poltergeist(app)
+          Capybara::Poltergeist::Driver.new(app, @options.merge(window_size: @screen_size))
+        end
+
+        def register_webkit(app)
+          Capybara::Webkit::Driver.new(app, Capybara::Webkit::Configuration.to_hash.merge(@options)).tap do |driver|
+            driver.resize_window(*@screen_size)
+          end
+        end
+
         def setup
           Capybara.current_driver = @name
         end
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 187ba2cc5f..f03f0d4299 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
@@ -2,7 +2,12 @@ module ActionDispatch
   module SystemTesting
     module TestHelpers
       module SetupAndTeardown # :nodoc:
-        DEFAULT_HOST = "127.0.0.1"
+        DEFAULT_HOST = "http://127.0.0.1"
+
+        def host!(host)
+          super
+          Capybara.app_host = host
+        end
 
         def before_setup
           host! DEFAULT_HOST