`before` block called before valid route is checked for.

On version 0.16.2, I have the following configured;

class Foos < Grape::API
  include AuthCheck
  ...
  resource :foo do
    ...
    get '/:foo/:id' do
      ...
    end

    # But no POST route
  end
end

module AuthCheck
  extend ActiveSupport::Concern

  included do
    before do
      error!('Unauthorized', 401) unless headers_has_secret
    end
  end
end

A GET request to foo/<foo-id> will either respond with a 200 or a 400 as expected. A POST however will 500;

ArgumentError (uncaught throw :error):
  app/api/my_auth_check.rb:8:in `block (2 levels) in <module:AuthCheck>'

Because it's a throw, this is the only line of the stack trace. If I force a throw and send a GET request I do get a big stack trace, which means the throw is caught in that case. If I write a post block, I get the expected behavior.

It seems like grape is running the before block before it checks to see whether the request has a matching route. Is this the intended behaviour?

Reproduce the shown API in app/api/my_auth_check.rb and compare the GET request with the POST request for a missing route. Trace Grape's route-matching and before-hook entry points to determine why the unauthorized throw is uncaught; done means the missing POST route follows the expected error behavior and the regression is covered by a test.