fix(#2236): Stripping the internals of Grape::Endpoint when NoMethodError is raised

[jcagarcia]

Hi all! 👋

My first contribution to the Grape project. Let's see if this can help to solve the issue #2236

With the fix, when referencing an undefined local variable within a grape controller, Grape is returning this error message.

(error trace updated after applying @dblock suggestions)

NoMethodError: undefined method `authenticate!' for #<Class:0x0000000103996728> in `/foo' endpoint
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:408:in `method_missing'
	/Users/Juancarlos.Garcia/code/grape-2236/api.rb:7:in `block in <class:MyAPI>'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:58:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:58:in `block (2 levels) in generate_api_method'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/activesupport-7.0.8/lib/active_support/notifications.rb:208:in `instrument'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:57:in `block in generate_api_method'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:328:in `execute'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:260:in `block in run'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/activesupport-7.0.8/lib/active_support/notifications.rb:208:in `instrument'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:240:in `run'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:316:in `block in build_stack'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/base.rb:36:in `call!'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/base.rb:29:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/error.rb:39:in `block in call!'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/error.rb:38:in `catch'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/error.rb:38:in `call!'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/middleware/base.rb:29:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/head.rb:12:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:224:in `call!'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/endpoint.rb:218:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router/route.rb:58:in `exec'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:120:in `process_route'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:74:in `block in identity'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:94:in `transaction'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:72:in `identity'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:56:in `block in call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:136:in `with_optimization'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/router.rb:55:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/api/instance.rb:165:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/api/instance.rb:70:in `call!'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/api/instance.rb:65:in `call'
	/Users/Juancarlos.Garcia/code/grape/lib/grape/api.rb:81:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/tempfile_reaper.rb:15:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/lint.rb:50:in `_call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/lint.rb:38:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/show_exceptions.rb:23:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/common_logger.rb:38:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/rack-2.2.8/lib/rack/content_length.rb:17:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/configuration.rb:252:in `call'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/request.rb:77:in `block in handle_request'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/thread_pool.rb:340:in `with_force_shutdown'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/request.rb:76:in `handle_request'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/server.rb:443:in `process_client'
	/Users/Juancarlos.Garcia/.rvm/gems/ruby-3.2.2/gems/puma-5.6.7/lib/puma/thread_pool.rb:147:in `block in spawn_thread'
127.0.0.1 - - [10/Nov/2023:10:14:40 +0100] "GET /foo HTTP/1.1" 500 154280 0.0466

Don't know the implications of overriding the method_missing for the Grape::Endpoint instance class. Also, don't know if you want to show more descriptive information a part of the anonymous class object. So suggestions, feedback or any kind of comment is really welcome :)

[dblock]

Very nice! See comments.

[dblock]

Also add a test when you do Object.new.x inside the API. I bet that with this change it references the wrong class where the error is raised (should be Object).

[jcagarcia]

Hey @dblock , thanks for the review and the suggestions!

I've just pushed two new commits for applying your suggestions.

1. The quotes now follows the ruby style using backtick and a quote.
2. I've included the API route in the error message. I'm using the route.origin method for getting the path, let me know if that's correct or if I should use a different method. Also let me know if the message is now fine or you have any other suggestion.
3. I've added a test for using Object.new.x inside the API. Seems that is referencing the correct class, as it is Object. I think this is because when performing the instance method is not entering in our method_missing method, so I think we are fine.
4. Performing rubocop and applying corrections.

Hope this changes help!

[dblock]

Great work, merged!