fix(#2236): Stripping the internals of Grape::Endpoint when NoMethodError is raised (#2368)

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

* fix(#2236): Follow quote ruby style and including the endpoint in the error message

* fix(#2236): Running rubocop and applying corrections

Author: jcagarcia

CHANGELOG.md

@@ -12,6 +12,7 @@
 
 * [#2364](https://github.com/ruby-grape/grape/pull/2364): Add missing requires - [@ericproulx](https://github.com/ericproulx).
 * [#2366](https://github.com/ruby-grape/grape/pull/2366): Default quality to 1.0 in the `Accept` header when omitted - [@hiddewie](https://github.com/hiddewie).
+* [#2368](https://github.com/ruby-grape/grape/pull/2368): Stripping the internals of `Grape::Endpoint` when `NoMethodError` is raised - [@jcagarcia](https://github.com/jcagarcia).
 * Your contribution here.
 
 ### 1.8.0 (2023/08/30)

lib/grape/endpoint.rb

@@ -403,5 +403,13 @@ def options?
       options[:options_route_enabled] &&
         env[Grape::Http::Headers::REQUEST_METHOD] == Grape::Http::Headers::OPTIONS
     end
+
+    def method_missing(name, *_args)
+      raise NoMethodError.new("undefined method `#{name}' for #{self.class} in `#{route.origin}' endpoint")
+    end
+
+    def respond_to_missing?(method_name, include_private = false)
+      super
+    end
   end
 end

spec/grape/endpoint_spec.rb

@@ -692,6 +692,30 @@ def app
     end
   end
 
+  describe '#method_missing' do
+    context 'when referencing an undefined local variable' do
+      it 'raises NoMethodError but stripping the internals of the Grape::Endpoint class and including the API route' do
+        subject.get('/hey') do
+          undefined_helper
+        end
+        expect do
+          get '/hey'
+        end.to raise_error(NoMethodError, %r{^undefined method `undefined_helper' for #<Class:0x[0-9a-fA-F]+> in `/hey' endpoint})
+      end
+    end
+
+    context 'when performing an undefined method of an instance inside the API' do
+      it 'raises NoMethodError but stripping the internals of the Object class' do
+        subject.get('/hey') do
+          Object.new.x
+        end
+        expect do
+          get '/hey'
+        end.to raise_error(NoMethodError, /^undefined method `x' for #<Object:0x[0-9a-fA-F]+>$/)
+      end
+    end
+  end
+
   it 'does not persist params between calls' do
     subject.post('/new') do
       params[:text]