NameError：未初始化的常量和 LoadError：无法自动加载常量

Question

After upgrade to Rails 5.0.1, I started getting intermittent NameError: uninitialized constant Payments::EventHandlers errors. Here is how my class is defined:

Code:

# app/managers/finance/payments/event_handlers/customer.rb
module Finance
  module Payments
    module EventHandlers
      class Customer < Finance::Payments::BaseStripeEventHandler
        # various methods
      end
    end
  end
end

# app/managers/finance/payments/base_stripe_event_handler.rb
module Finance
  module Payments
    class BaseStripeEventHandler < Finance::BaseStripeEventHandler
      # various methods
    end
  end
end

# app/managers/finance/base_stripe_event_handler.rb
module Finance
  class BaseStripeEventHandler
    # various methods
  end
end

I was able to reproduce this error on Rails console as below:

Loading staging environment (Rails 5.0.1)
2.4.6 :001 > Finance::Payments::EventHandlers::Customer
 => Finance::Payments::EventHandlers::Customer
2.4.6 :002 > reload!
Reloading...
 => true
2.4.6 :003 > Finance::Payments::EventHandlers::Customer
NameError: uninitialized constant Finance

So following https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#autoloading-is-disabled-after-booting-in-the-production-environment , I modified my config/application.rb file as below:

    config.eager_load_paths += %W(#{config.root}/lib)
    config.enable_dependency_loading = true
    config.autoload_paths += %W(#{config.root}/lib)

After these changes, I started getting LoadError: Unable to autoload constant :

Loading staging environment (Rails 5.0.1)
2.4.6 :001 > Finance::Payments::EventHandlers::Customer
 => Finance::Payments::EventHandlers::Customer
2.4.6 :002 > reload!
Reloading...
 => true
2.4.6 :003 > Finance::Payments::EventHandlers::Customer
LoadError: Unable to autoload constant Finance::Payments::EventHandlers::Customer, expected .../app/managers/finance/payments/event_handlers/customer.rb to define it

I am not clear if it is a directory structure issue or the way customer class is defined. Can someone provide guidance on how to fix it?

Thanks.

Edits I removed config.autoload_paths += %W(#{config.root}/lib) from config/application.rb and it is still giving same results. Appreciate any help on this!

Edits 2 (implement suggestion by Roman Alekseiev )

As suggested by Roman Alekseiev, I added below:

# app/managers/finance.rb
module Finance; end

# app/managers/finance/payments.rb
module Finance
  module Payments
  end
end

# app/managers/finance/payments/event_handlers.rb
module Finance
  module Payments
    module EventHandlers
    end
  end
end

After these changes, I think I have made some progress as above NameError is not occurring in the console anymore after reload! .

But when my worker runs this job, it is still returning this NameError: Worker is executing below code:

scope = "Payments" # conditionally assigned
handler_class = "Invoice" # again, conditionally assigned
constant_name = "::Finance::#{scope}::EventHandlers::#{handler_class[:handler]}" # in this case ::Finance::Payments::EventHandlers::Invoice
Object.const_get(constant_name) 

Last statement above returns NameError: uninitialized constant Payments::EventHandlers

# app/managers/finance/payments/event_handlers/invoice.rb
module Finance
  module Payments
    module EventHandlers
      class Invoice < Finance::Payments::BaseStripeEventHandler
        # various methods
      end
    end
  end
end

Answer 1

I am not sure but as a suggestion what if you add this file and code to your structure. Under app/managers directory create file finance.rb with code below

module Finance; end

Under app/managers/finance create file payments.rb with code below

module Finance
  module Payments
  end
end

Under app/managers/finance/payments create file (if not exist) event_handlers.rb with code

module Finance
  module Payments
    module EventHandlers
    end
  end
end

I had similar problem, this approach helped, hope it will help you also

Answer 2

This actually depends upon your folder structure. Not sure where you want your base_event_handler.rb file to be ? Do you want to keep it inside event_handlers folder or inside payments folder ?

This should be the structure if you want the base_event_handler.rb file to be inside event_handlers folder :

module Finance
  module Payments
    module EventHandlers
      class Customer < Finance::Payments::EventHandlers::BaseEventHandler
        def method1
          puts "Hello there ---"
        end
      end
    end
  end
end

NOTE: Do define your base_event_handler.rb file too, else you will be getting NameError for not defining :

module Finance
  module Payments
    module EventHandlers
      class BaseEventHandler
        def methodE
          puts "This base event"
        end
      end
    end
  end
end