Forum: Rails-core (closed, excessive spam) has_many_through_associations bug when set_primary_key used

I have three classes defined like this:

class Campaign < ActiveRecord::Base

  has_many :urls, :foreign_key => 'campaignid'
  has_many :stats, :through => :urls

  set_table_name 'campaign'
  set_primary_key 'campaignid'
end

class Url < ActiveRecord::Base
  belongs_to :campaign, :foreign_key => 'campaignid'
  has_many :stats, :foreign_key => 'urlid'

  set_table_name 'url'
  set_primary_key 'urlid'
end

class Stat < ActiveRecord::Base
  belongs_to :url, :foreign_key => 'urlid'

  set_primary_key 'statsid'
end

When I drop into the console and try this:

>> c = Campaign.find(:first)
>> c.stats

I get this:

ActiveRecord::StatementInvalid: Mysql::Error: #42S22Unknown column
'url.statsid' in 'on clause': SELECT `stats`.* FROM `stats`    INNER
JOIN url ON stats.urlid = url.statsid    WHERE ((`url`.campaignid = 1))
        from
/Library/Ruby/Gems/1.8/gems/activerecord-2.1.0/lib/active_record/connection_adapters/abstract_adapter.rb:147:in
`log'

It looks like the inner join is being improperly constructed.   It
should say

INNER JOIN ON stats.urlid = url.urlid

Or, to put it more generically:

INNER JOING ON <association_table>.<intermediate_table_fk> =
<intermediate_table>.<intermediate_table_pk>

But it is currently doing:

INNER JOING ON <association_table>.<intermediate_table_fk> =
<intermediate_table>.<associate_table_pk>

I think this boils down to
activerecord-2.1.0/lib/active_record/associations/has_many_through_association.rb:150-155

I think this would be easy to miss since :through associations aren't
entirely common and renaming your primary key is also not common so any
table's primary key is getting used.  I'm going to do a workaround that
doesn't use the :through association for now.

> I think this would be easy to miss since :through associations aren't
> entirely common and renaming your primary key is also not common so any
> table's primary key is getting used.  I'm going to do a workaround that
> doesn't use the :through association for now.

Hi there,

this definitely sounds like you've found a bug.  The best bet would be
to jump into the #rails-contrib irc channel on freenode, and ask for
some help coming up with a patch to fix this, and include tests.

The mechanics of contributing a git patch are covered in:

http://rails.lighthouseapp.com/projects/8994/sending-patches


--
Cheers

Koz