has_one :through supports :source_type. Fix up some tests. References #4756.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9075 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/association_preload.rb

@@ -165,8 +165,13 @@ def preload_through_records(records, reflection, through_association)
           through_records = []
           records.compact.each do |record|
             proxy = record.send(through_association)
-            through_records << proxy.target
-            proxy.reset
+
+            if proxy.respond_to?(:target)
+              through_records << proxy.target
+              proxy.reset
+            else # this is a has_one :through reflection
+              through_records << proxy if proxy
+            end
           end
           through_records = through_records.flatten
         else

activerecord/lib/active_record/associations.rb

@@ -1326,7 +1326,7 @@ def create_has_one_reflection(association_id, options)
         
         def create_has_one_through_reflection(association_id, options)
           options.assert_valid_keys(
-            :class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as, :through, :source
+            :class_name, :foreign_key, :remote, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as, :through, :source, :source_type
           )
           create_reflection(:has_one, association_id, options, self)
         end

activerecord/test/cases/associations_test.rb

@@ -526,16 +526,27 @@ def has_one_through_to_has_many
   end
   
   def test_has_one_through_eager_loading
-    members = Member.find(:all, :include => :club)
-    assert_equal 2, members.size
+    members = Member.find(:all, :include => :club, :conditions => ["name = ?", "Groucho Marx"])
+    assert_equal 1, members.size
     assert_not_nil assert_no_queries {members[0].club}
   end
   
   def test_has_one_through_eager_loading_through_polymorphic
-    members = Member.find(:all, :include => :sponsor_club)
-    assert_equal 2, members.size
+    members = Member.find(:all, :include => :sponsor_club, :conditions => ["name = ?", "Groucho Marx"])
+    assert_equal 1, members.size
     assert_not_nil assert_no_queries {members[0].sponsor_club}    
   end
+
+  def test_has_one_through_polymorphic_with_source_type
+    assert_equal members(:groucho), clubs(:moustache_club).sponsored_member
+  end
+
+  def test_eager_has_one_through_polymorphic_with_source_type
+    clubs = Club.find(:all, :include => :sponsored_member, :conditions => ["name = ?","Moustache and Eyebrow Fancier Club"])
+    # Only the eyebrow fanciers club has a sponsored_member
+    assert_not_nil assert_no_queries {clubs[0].sponsored_member}
+  end
+
 end
 
 class HasManyAssociationsTest < ActiveRecord::TestCase

activerecord/test/fixtures/sponsors.yml

@@ -1,3 +1,9 @@
 moustache_club_sponsor_for_groucho:
   sponsor_club: moustache_club
-  sponsorable: groucho (Member)
+  sponsorable: groucho (Member)
+boring_club_sponsor_for_groucho:
+  sponsor_club: boring_club
+  sponsorable: some_other_guy (Member)
+crazy_club_sponsor_for_groucho:
+  sponsor_club: crazy_club
+  sponsorable: some_other_guy (Member)

activerecord/test/models/club.rb

@@ -2,5 +2,6 @@ class Club < ActiveRecord::Base
   has_many :memberships
   has_many :members, :through => :memberships
   has_many :current_memberships
-  has_many :sponsors
+  has_one :sponsor
+  has_one :sponsored_member, :through => :sponsor, :source => :sponsorable, :source_type => "Member"
 end