Hello,

I found named_scope is buggy with has_many :through when the 2 models do have the same column name used by the scope.

class User < AR::Base
  has_many :friendships
  has_many :friends, :class_name => 'User', :through => :friendships
end

class Friendship < AR::Base
  belongs_to :user
  belongs_to :friend, :class_name => 'User', :foreign_key => 'friend_id'

  named_scope :pending,  :conditions => { :state => 'pending' }
  named_scope :accepted, :conditions => { :state => 'accepted' }
  named_scope :denied,   :conditions =>  { :state => 'denied' }
end

>> User.first.friendships.pending
=> []
# SELECT "users".* FROM "users" INNER JOIN friendships ON users.id = friendships.friend_id WHERE (("friendships".user_id = 1)) AND ("users"."state" = E'pending')

See ?

The SQL query takes "users"."state" instead of "friendships"."state".

Now the weirderst part:

class Friendship < AR::Base
  belongs_to :user
  belongs_to :friend, :class_name => 'User', :foreign_key => 'friend_id'

  named_scope :pending,  :conditions => { 'friendships.state' => 'pending' }
  named_scope :accepted, :conditions => { 'friendships.state' => 'accepted' }
  named_scope :denied,   :conditions => { 'friendships.state' => 'denied' }
end

Declaring the table name in the :conditions hash doesn't change anything ! It still queries "users"."state" !

The only way I found to solve this issue is to double the friendships named_scope in the user model !!

class User < ActiveRecord::Base
  has_many :friendships
  has_many :friends, :class_name => 'User', :through => :friendships
  named_scope :pending,  :conditions => { 'friendships.state' => 'pending' }
  named_scope :accepted, :conditions => { 'friendships.state' => 'accepted' }
  named_scope :denied,   :conditions => { 'friendships.state' => 'denied' }
 end

of course the following will raise an error:

>> User.first.pending

but this call won't now:

>> User.first.friends.pending
=> [#<User id: 7701,... >]