[Rails] Re: Stack overflow problem

[Eric Anderson]

Eric Anderson wrote:
> So I would GREATLY appreciate anyone that could clue me into why this 
> problem is showing up so I could look for a work-around.

I think I found the problem after lots of code searching. It looks like 
the :foreign_key option cannot be the same as the attribute name. This 
is because when finding the associated class it called the raw field 
name as a method to get the actual value of the field to search on. It 
is somewhat equivalent to:

class User

	def account_id
		read_attribute "account_id"
	end

	def account
		Account.find( account_id )
	end

end

Of course the real code is generated and more dynamic than above, but 
that is the essence of how it is working. If :foreign_key is equal to 
the attribute name then you effectively have:

class User

	# This method is created by method_missing()
	def account
		read_attribute "account"
	end

	def account
		Account.find( account )
	end

end


Obviously the first definition (which really doesn't exist but is being 
created by method_missing) is irrelevant because the second definition 
is real (through a module_eval) and therefore when the second method is 
called it will keep recursively calling itself.

So the next question is now that I have found the problem how do we fix 
it. It seems the obvious answer is to change line 338-340 of 
associations.rb to the following:

association_finder = options[:conditions] ?
"#{association_class_name}.find_on_conditions(read_attribute(\"#{association_class_primary_key_name}\"), 
\"#{options[:conditions]}\")" : 
"#{association_class_name}.find(read_attribute(\"#{association_class_primary_key_name}\"))"

Email wrapping may mess this up but basically we want to make it use the 
underlying read_attribute method instead of the public accessor method. 
This shouldn't break compatibility too much. The only harm is if a user 
has overwritten the account_id method to make it load a different object 
from what the database says it should load. But I imagine this would be 
rare (if used at all by anyone).

I'm going to make the changes on my system to see if it works. I would 
appreciate any comments about better approaches or any comments about 
possible problems related to this.

Thanks,

Eric
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