Fix eager loading of polymorphic has_one associations nested-included under...

Fix eager loading of polymorphic has_one associations nested-included under polymorphic belongs_to associations. [#3233 state:resolved]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

activerecord/lib/active_record/association_preload.rb

@@ -357,7 +357,13 @@ def find_associated_records(ids, reflection, preload_options)
         table_name = reflection.klass.quoted_table_name
 
         if interface = reflection.options[:as]
-          conditions = "#{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_id"} #{in_or_equals_for_ids(ids)} and #{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_type"} = '#{self.base_class.sti_name}'"
+          parent_type = if reflection.active_record.abstract_class?
+            self.base_class.sti_name
+          else
+            reflection.active_record.sti_name
+          end
+
+          conditions = "#{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_id"} #{in_or_equals_for_ids(ids)} and #{reflection.klass.quoted_table_name}.#{connection.quote_column_name "#{interface}_type"} = '#{parent_type}'"
         else
           foreign_key = reflection.primary_key_name
           conditions = "#{reflection.klass.quoted_table_name}.#{foreign_key} #{in_or_equals_for_ids(ids)}"

activerecord/test/cases/associations/eager_load_nested_polymorphic_include.rb

+require 'cases/helper'
+require 'models/tee'
+require 'models/tie'
+require 'models/polymorphic_design'
+require 'models/polymorphic_price'
+
+class EagerLoadNestedPolymorphicIncludeTest < ActiveRecord::TestCase
+  fixtures :tees, :ties, :polymorphic_designs, :polymorphic_prices
+
+  def test_eager_load_polymorphic_has_one_nested_under_polymorphic_belongs_to
+    designs = PolymorphicDesign.scoped(:include => {:designable => :polymorphic_price})
+
+    associated_price_ids = designs.map{|design| design.designable.polymorphic_price.id}
+    expected_price_ids = [1, 2, 3, 4]
+
+    assert expected_price_ids.all?{|expected_id| associated_price_ids.include?(expected_id)},
+      "Expected associated prices to be #{expected_price_ids.inspect} but they were #{associated_price_ids.sort.inspect}"
+  end
+end

activerecord/test/fixtures/polymorphic_designs.yml

+awesome_tee_design:
+  id: 1
+  designable_id: 1
+  designable_type: Tee
+
+sucky_tee_design:
+  id: 2
+  designable_id: 2
+  designable_type: Tee
+
+awesome_hat_design:
+  id: 3
+  designable_id: 1
+  designable_type: Tie
+
+sucky_hat_design:
+  id: 4
+  designable_id: 2
+  designable_type: Tie
\ No newline at end of file

activerecord/test/fixtures/polymorphic_prices.yml

+awesome_tee_price:
+  id: 1
+  sellable_id: 1
+  sellable_type: Tee
+
+sucky_tee_price:
+  id: 2
+  sellable_id: 2
+  sellable_type: Tee
+
+awesome_hat_price:
+  id: 3
+  sellable_id: 1
+  sellable_type: Tie
+
+sucky_hat_price:
+  id: 4
+  sellable_id: 2
+  sellable_type: Tie
\ No newline at end of file

activerecord/test/fixtures/tees.yml

+awesome_tee:
+  id: 1
+sucky_tee:
+  id: 2
\ No newline at end of file

activerecord/test/fixtures/ties.yml

+awesome_tie:
+  id: 1
+sucky_tie:
+  id: 2
\ No newline at end of file

activerecord/test/models/polymorphic_design.rb

+class PolymorphicDesign < ActiveRecord::Base
+  belongs_to :designable, :polymorphic => true
+end
\ No newline at end of file

activerecord/test/models/polymorphic_price.rb

+class PolymorphicPrice < ActiveRecord::Base
+  belongs_to :sellable, :polymorphic => true
+end
\ No newline at end of file

activerecord/test/models/tee.rb

+class Tee < ActiveRecord::Base
+  has_one :polymorphic_design, :as => :designable
+  has_one :polymorphic_price, :as => :sellable
+end
\ No newline at end of file

activerecord/test/models/tie.rb

+class Tie < ActiveRecord::Base
+  has_one :polymorphic_design, :as => :designable
+  has_one :polymorphic_price, :as => :sellable
+end
\ No newline at end of file

activerecord/test/schema/schema.rb

@@ -367,6 +367,16 @@ def create_table(*args, &block)
     t.column :updated_on, :datetime
   end
 
+  create_table :polymorphic_designs, :force => true do |t|
+    t.integer :designable_id
+    t.string  :designable_type
+  end
+
+  create_table :polymorphic_prices, :force => true do |t|
+    t.integer :sellable_id
+    t.string  :sellable_type
+  end
+
   create_table :posts, :force => true do |t|
     t.integer :author_id
     t.string  :title, :null => false
@@ -435,6 +445,8 @@ def create_table(*args, &block)
     t.datetime :ending
   end
 
+  create_table :ties, :force => true
+
   create_table :topics, :force => true do |t|
     t.string   :title
     t.string   :author_name
@@ -462,6 +474,8 @@ def create_table(*args, &block)
     t.column :taggings_count, :integer, :default => 0
   end
 
+  create_table :tees, :force => true
+
   create_table :toys, :primary_key => :toy_id ,:force => true do |t|
     t.string :name
     t.integer :pet_id, :integer