2 files changed, 13 insertions, 9 deletions
diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
index a2a80f39fc..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
@@ -7,10 +9,10 @@ module ActionDispatch
       ENV_SESSION_KEY         = Rack::RACK_SESSION # :nodoc:
       ENV_SESSION_OPTIONS_KEY = Rack::RACK_SESSION_OPTIONS # :nodoc:
 
-      # Singleton object used to determine if an optional param wasn't specified
+      # Singleton object used to determine if an optional param wasn't specified.
       Unspecified = Object.new
 
-      # Creates a session hash, merging the properties of the previous session if any
+      # Creates a session hash, merging the properties of the previous session if any.
       def self.create(store, req, default_options)
         session_was = find req
         session     = Request::Session.new(store, req)
@@ -63,7 +65,7 @@ module ActionDispatch
         @req      = req
         @delegate = {}
         @loaded   = false
-        @exists   = nil # we haven't checked yet
+        @exists   = nil # We haven't checked yet.
       end
 
       def id
@@ -79,7 +81,7 @@ module ActionDispatch
         options = self.options || {}
         @by.send(:delete_session, @req, options.id(@req), options)
 
-        # Load the new sid to be written with the response
+        # Load the new sid to be written with the response.
         @loaded = false
         load_for_write!
       end
@@ -101,11 +103,13 @@ 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 01bc871e5f..0ae464082d 100644
--- a/actionpack/lib/action_dispatch/request/utils.rb
+++ b/actionpack/lib/action_dispatch/request/utils.rb
@@ -1,8 +1,9 @@
+# frozen_string_literal: true
+
 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
@@ -33,14 +34,13 @@ module ActionDispatch
           unless params.valid_encoding?
             # Raise Rack::Utils::InvalidParameterError for consistency with Rack.
             # ActionDispatch::Request#GET will re-raise as a BadRequest error.
-            raise Rack::Utils::InvalidParameterError, "Non UTF-8 value: #{params}"
+            raise Rack::Utils::InvalidParameterError, "Invalid encoding for parameter: #{params.scrub}"
           end
         end
       end
 
       class ParamEncoder # :nodoc:
         # Convert nested Hash to HashWithIndifferentAccess.
-        #
         def self.normalize_encode_params(params)
           case params
           when Array
@@ -63,7 +63,7 @@ module ActionDispatch
         end
       end
 
-      # Remove nils from the params hash
+      # Remove nils from the params hash.
       class NoNilParamEncoder < ParamEncoder # :nodoc:
         def self.handle_array(params)
           list = super