3 files changed, 9 insertions, 12 deletions
diff --git a/actionpack/lib/action_dispatch/http/parameter_filter.rb b/actionpack/lib/action_dispatch/http/parameter_filter.rb
index e826551f4b..01f1666b9b 100644
--- a/actionpack/lib/action_dispatch/http/parameter_filter.rb
+++ b/actionpack/lib/action_dispatch/http/parameter_filter.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/object/duplicable'
+
 module ActionDispatch
   module Http
     class ParameterFilter
diff --git a/actionpack/lib/action_dispatch/http/parameters.rb b/actionpack/lib/action_dispatch/http/parameters.rb
index ff5031d7d5..3f0e51790c 100644
--- a/actionpack/lib/action_dispatch/http/parameters.rb
+++ b/actionpack/lib/action_dispatch/http/parameters.rb
@@ -44,7 +44,14 @@ module ActionDispatch
 
       def path_parameters=(parameters) #:nodoc:
         delete_header('action_dispatch.request.parameters')
+
+        # If any of the path parameters has an invalid encoding then
+        # raise since it's likely to trigger errors further on.
+        Request::Utils.check_param_encoding(parameters)
+
         set_header PARAMETERS_KEY, parameters
+      rescue Rack::Utils::ParameterTypeError, Rack::Utils::InvalidParameterError => e
+        raise ActionController::BadRequest.new("Invalid path parameters: #{e.message}")
       end
 
       # Returns a hash with the \parameters used to form the \path of the request.
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index b0ed681623..954dd4f354 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -66,24 +66,12 @@ module ActionDispatch
     def commit_cookie_jar! # :nodoc:
     end
 
-    def check_path_parameters!
-      # If any of the path parameters has an invalid encoding then
-      # raise since it's likely to trigger errors further on.
-      path_parameters.each do |key, value|
-        next unless value.respond_to?(:valid_encoding?)
-        unless value.valid_encoding?
-          raise ActionController::BadRequest, "Invalid parameter encoding: #{key} => #{value.inspect}"
-        end
-      end
-    end
-
     PASS_NOT_FOUND = Class.new { # :nodoc:
       def self.action(_); self; end
       def self.call(_); [404, {'X-Cascade' => 'pass'}, []]; end
     }
 
     def controller_class
-      check_path_parameters!
       params = path_parameters
 
       if params.key?(:controller)