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#2459 ✓stale
Tatsuya Ono

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

Reported by Tatsuya Ono | April 8th, 2009 @ 07:54 PM | in 3.x

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.


in app/models/sample.rb:

class Sample < ActiveRecord::Base
  def reproduce_issue

in app/models/sample/sample_class.rb:

class SampleClass < ActiveRecord::Base


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


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.


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

Comments and changes to this ticket

  • Tom Stuart

    Tom Stuart April 17th, 2009 @ 02:36 PM

    This bit me too. I'm not 100% convinced by the solution. I just renamed my model directories to not clash with any class names (i.e. pluralized them). But that's not really a fix either!

  • Jeremy Kemper

    Jeremy Kemper May 4th, 2010 @ 06:48 PM

    • Milestone changed from 2.x to 3.x
  • Santiago Pastorino

    Santiago Pastorino February 2nd, 2011 @ 05:03 PM

    • State changed from “new” to “open”
    • Tag changed from 2.x, active_support, const_missing, dependencies.rb to 2x, active_support, const_missing, dependenciesrb
    • Importance changed from “” to “”

    This issue has been automatically marked as stale because it has not been commented on for at least three months.

    The resources of the Rails core team are limited, and so we are asking for your help. If you can still reproduce this error on the 3-0-stable branch or on master, please reply with all of the information you have about it and add "[state:open]" to your comment. This will reopen the ticket for review. Likewise, if you feel that this is a very important feature for Rails to include, please reply with your explanation so we can consider it.

    Thank you for all your contributions, and we hope you will understand this step to focus our efforts where they are most helpful.

  • Santiago Pastorino

    Santiago Pastorino February 2nd, 2011 @ 05:03 PM

    • State changed from “open” to “stale”

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