ActiveSupport::Dependencies::load_missing_constant() fails to load

Class autoload would be failed if the class to be loaded was located in the directory whose name is same as the class to load.

Example

in app/models/sample.rb:

class Sample < ActiveRecord::Base
  def reproduce_issue
    SampleClass
  end
end

in app/models/sample/sample_class.rb:

class SampleClass < ActiveRecord::Base

end

reproduce_issue() method would be failed even if you added 'app/models/sample' into config.load_paths.

It would rise exception with the following message:

Expected [RAILS_ROOT]/app/models/sample/sample_class.rb to define Sample::SampleClass

Problem

There is a problem on the following line in ActiveSupport::Dependencies::load_missing_constant()

raise LoadError, "Expected #{file_path} to define #{qualified_name}" unless uninherited_const_defined?(from_mod, const_name)

uninherited_const_defined? checks in the given class but not its super class. In above example, even if SampleClass was loaded, it returns false because it is not Sample::SampleClass.

Why other classes are OK?

file_path = search_for_file(path_suffix)

This line in ActiveSupport::Dependencies::load_missing_constant() would return nil for those which doesn't have 'sample' as a stored directory. Therefore it doesn't get affected this problem.

Solution

Need to check if the class is defined in the context of the super classes (especially in Object). I attach a patch.