weird behavior of belongs_to referencing a model with set_table_name : a bug?

Hello all,
Since nobody answered the letter below in rubyonrails-talk, I've taken the
courage to repost it here.
I looks like a bug, but I just refuse to believe it as it is such a basic
functionality of Active Record.

---------- Forwarded message ----------
From: Yuri Leikind <[e-mail]>
Date: 5 feb. 2008 13:24
Subject: weird behavior of belongs_to referencing a model with
set_table_name
To: [e-mail]

Hello all,

I am experiencing some really weird behavior of belongs_to with a model
where the table name is set by set_table_name


I have two simple models:


=== file legal_entity.rb


class LegalEntity < ActiveRecord::Base
  set_table_name 'legalentities'
end




=== file legal_entity_person.rb


class LegalEntityPerson < ActiveRecord::Base

  set_table_name 'legalentities_people'

  belongs_to :legal_entity, :foreign_key => ' legalentity_id'
end


=====


If I find a LegalEntityPerson object with :include => :legal_entity it works
as expected:

$  ./script/runner  'a = LegalEntityPerson.find(:first, :include =>
:legal_entity); p a.legal_entity'
#<LegalEntity id: 1, name: "Some Company", legalentitytype_id: 3>


and looking a the log I see the select method with the 2 tables joined, it's
fine.


Now, if I drop :include => :legal_entity, a.legal_entity returns nil:


$  ./script/runner 'a = LegalEntityPerson.find(:first); p a.legal_entity'
nil


And what is interesting is that there is no SQL query to the DB, that is,
there is  SELECT * FROM `legalentities_people` LIMIT 1 for the find
method, and nothing else, a.legal_entity silently returns nil without any
warnings or complaints.




If I rewrite my models like this following naming conventions:


=== file legalentity.rb


class Legalentity < ActiveRecord::Base


end




=== file legal_entity_person.rb


class LegalEntityPerson < ActiveRecord::Base

  set_table_name 'legalentities_people'

  belongs_to :legalentity
end


=====


it works:


$  ./script/runner 'a = LegalEntityPerson.find(:first); p a.legalentity'
#<Legalentity id: 1, name: "Some Company", legalentitytype_id: 3>




BUT!!!


If I specify :foreign_key explicitly like this:


  belongs_to :legalentity, :foreign_key => ' legalentity_id'



it doesn't work again:




Is there any reason behind this behavior or is it a bug?


I am using Rails 2.0.2,  mysql 5.0.51a, all running on OS X, and with the
following sql code you can reproduce it:


CREATE TABLE `legalentities` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `name` varchar(255) NOT NULL,
  `legalentitytype_id` int(10) unsigned NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;


INSERT INTO `legalentities` VALUES (1,'Some Company',3);


CREATE TABLE `legalentities_people` (
  `id` int(10) unsigned NOT NULL auto_increment,
  `legalentity_id` int(10) unsigned NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;


INSERT INTO `legalentities_people` VALUES (1,1);

-- 
Best regards,
Yuri Leikind