[WIP] Allow users to opt-out from the ActionController extensions

[bf4]

Purpose

• Make it possible to require active_model_serializers without mixing ActionController::Serialization into the controller

Changes

Add ActionController::Serialization.enabled = false to an initializer and it won't be mixed in.

Caveats

This doesn't exactly solve #1500 since it doesn't include any AMS code in the controller, and passing serializer or each_serializer won't work

Perhaps config should come from Rails, rather than be set on the mixin. e.g.

Rails.configuration.action_controller.render_json_with_active_model_serializers = false

Related GitHub issues

• Explicit serializer_lookup_enabled in controller doesn't retain Adapter for entire render  #1500
• Allow users to opt-out from the ActionController extensions #592

And many more

Additional helpful information

cc @trek

[bf4]

I marked this as WIP since I'd like to think over the implementation a bit and this also needs tests.

[NullVoxPopuli]

I like the idea of setting the option in the rails config.

[bf4]

(pardon the awful pseudo code)

I was actually just thinking about having

• a configurable default 'ams_ify_controller = true`
• and then in the controller, by default we only mix in a 'shim' module that
  • has config methods, e.g. ams_ify_controller
  • so that by default ActionController::Serialization would be included in action controller
  • but if the default were set to false, then individual controllers would need to opt in by setting ams_ify_controller true .
  • the method would just extend the controller with ActionController::Serialization when true