does not show hidden namespaces in generator's help

railties/lib/rails/commands/generate/generate_command.rb

@@ -4,6 +4,9 @@ module Rails
   module Command
     class GenerateCommand < Base # :nodoc:
       def help
+        require_application_and_environment!
+        load_generators
+
         Rails::Generators.help self.class.command_name
       end
 

railties/test/application/generators_test.rb

@@ -184,5 +184,12 @@ module ApplicationTests
 
       Rails::Command.send(:remove_const, "APP_PATH")
     end
+
+    test "help does not show hidden namespaces" do
+      FileUtils.cd(rails_root) do
+        output = `bin/rails generate --help`
+        assert_no_match "active_record:migration", output
+      end
+    end
   end
 end