Rails 3 library not loading until require

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Auto-loading works fine as long as the class in your file is a class that is only defined in that file. It doesn’t work if you’re wanting to re-open an existing class (originally defined in standard Ruby, Rails, or another library) and customize it in some way.

Example of problem:

Here’s an example of a file in lib/ that would never get autoloaded:

lib/active_record/base_extensions.rb:

ActiveRecord::Base   # make sure ActiveRecord::Base is loaded
module ActiveRecord::Base::Extensions
  # some methods here
end

class ActiveRecord::Base
  include ActiveRecord::Base::Extensions
end

This file reopens ActiveRecord::Base and adds some methods to that class.

What would trigger this file to get autoloaded?? Nothing! Auto-loading is based on constants, and the constant ActiveRecord::Base has already been loaded (from the activerecord gem).

So referencing the constant ActiveRecord::Base in your app would not cause this particular file to be auto-loaded.

Workaround:

This is what I do to ensure that all my Ruby files under lib/ get required:

Add a new initializer named config/initializers/require_files_in_lib.rb with this contents:

Dir[Rails.root + 'lib/**/*.rb'].each do |file|
  require file
end

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