Cache_store not set when using ActionCtrl::API and manually including Caching

[dennym]

Steps to reproduce

Simple setup some cache_store for the Application

# application.rb
config.api_only = true
config.cache_store = :mem_cached_store`

# application_controller.rb
class ApplicationController < ActionController::API
  include ::ActionController::Caching
end

Actual behavior

Since I have config.action_controller.perform_caching = true I was checking if my dalli store was available since I use ActionController::API. After digging through the repository I found out I had to include manually ActionController::Caching. Ezpz but after checking for cache_store it turns out that the cache store is nil and therefor not set.

# application_controller.rb
class ApplicationController < ActionController::API
  include ::ActionController::Caching
end

ApplicationController.cache_store #=> nil

To eliminate any other configuration errors I just checked against having the ApplicationController inherit from ActionController::Base and there it returns the expected cache store.

# application_controller.rb
class ApplicationController < ActionController::Base
end

ApplicationController.cache_store #=> :mem_cached_store ...

Expected behavior

Well both setups should give the same output. Its also mentioned here that the modules can be included.

As a side thought:
When you rails new foo --api then it sets ApplicationController to ActionController::API instead of Base and also sets production to config.action_controller.perform_caching = true Which wouldn't work then at all.

System configuration

Rails version: 5.2.2

Ruby version: 2.6.1

[st0012]

@dennym FYI, I already opened a PR for that. I hope them would accept it and backport it to 5.2 😄

[dennym]

Mhm interesting... thanks for the input and work :) So the cache_store in the controller is just responsible for view caching? I was under the impression that it does couple of magical caching in the background.

If its its just for view caching I personally actually don't need it. But when setting a new rails project up with rails new foo --api it shouldn't set config.action_controller.perform_caching = true since this is probably won't have any use, right?

[rafaelfranca]

But when setting a new rails project up with rails new foo --api it shouldn't set config.action_controller.perform_caching = true since this is probably won't have any use, right?

That is a good point. We need to double check if that config affects other things but I believe we can remove from the api apps.