How to permit concurrent loads in Rails 4.2?

[vaibhavatul47]

Steps to reproduce

When writing a multithreaded application it is advised to enable concurrent loads to avoid deadlock during autoloading.

ActiveSupport::Dependencies.interlock.permit_concurrent_loads

link to guide

The example in the guide is for Rails 5, how can I achieve this in Rails 4.2? I couldn't find interlock.rb file inside active_support/dependencies directory.

Expected behavior

  futures = @current_user.posts.map do |p|
      Concurrent::Promises.future(p) do |post|
        ActiveRecord::Base.connection_pool.with_connection do
          post.cleanup_comments # Calls an API which takes ~2minutes
          post.destroy
        end
      end
    end

    responses = futures.map(&:value)

This code should be able to destroy all posts of current-user concurrently.

Actual behavior

When I execute this code I get: Circular dependency detected while autoloading constant error

Note: I was able to solve this problem by putting these two lines in my config/application.rb file, but I'm not sure if thats the correct way to solve this circular dependency deadlock issue.

config.cache_classes = true
config.eager_load = true

System configuration

Rails version: rails -v # Rails 4.2.8

Ruby version: ruby -v # ruby 2.3.4p301 (2017-03-30 revision 58214) [x86_64-darwin18]

[kaspth]

You can’t because it was added for Rails 5.0 iirc. Rails 4.2 is unsupported now, so the only to be able to enable that is to upgrade your Rails app. Thanks!