Merge pull request #29533 from jdelStrother/missing_url_formats

Fix missing formats in route-set URLs

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -248,6 +248,8 @@ def handle_positional_args(controller_options, inner_options, args, result, path
               if args.size < path_params_size
                 path_params -= controller_options.keys
                 path_params -= result.keys
+              else
+                path_params = path_params.dup
               end
               inner_options.each_key do |key|
                 path_params.delete(key)

actionpack/test/dispatch/routing/route_set_test.rb

@@ -138,6 +138,15 @@ def call(env)
         assert_equal '/a/users/1', url_helpers.user_path(1, foo: 'a')
       end
 
+      test "implicit path components consistently return the same result" do
+        draw do
+          resources :users, to: SimpleApp.new("foo#index")
+        end
+        assert_equal "/users/1.json", url_helpers.user_path(1, :json)
+        assert_equal "/users/1.json", url_helpers.user_path(1, format: :json)
+        assert_equal "/users/1.json", url_helpers.user_path(1, :json)
+      end
+
       private
         def draw(&block)
           @set.draw(&block)