Merge pull request #37644 from ryan-robeson/fix-37543-generator-class-collision

Fix the collision check for the scaffold generator

railties/lib/rails/generators/named_base.rb

@@ -213,7 +213,7 @@ def mountable_engine? # :doc:
         #
         def self.check_class_collision(options = {}) # :doc:
           define_method :check_class_collision do
-            name = if respond_to?(:controller_class_name) # for ResourceHelpers
+            name = if respond_to?(:controller_class_name, true) # for ResourceHelpers
               controller_class_name
             else
               class_name

railties/test/generators/scaffold_controller_generator_test.rb

@@ -303,4 +303,12 @@ def test_api_only_generates_params_for_attachments
       assert_match(/params\.require\(:message\)\.permit\(:video, photos: \[\]\)/, content)
     end
   end
+
+  def test_check_class_collision
+    Object.send :const_set, :UsersController, Class.new
+    content = capture(:stderr) { run_generator }
+    assert_match(/The name 'UsersController' is either already used in your application or reserved/, content)
+  ensure
+    Object.send :remove_const, :UsersController
+  end
 end