0
@@ -1,5 +1,7 @@
0
 *1.15.3* (March 12th, 2007)
0
 
0
+* Allow a polymorphic :source for has_many :through associations. Closes #7143 [protocool] 
0
+
0
 * Consistently quote primary key column names.  #7763 [toolmantim]
0
 
0
 * Fixtures: fix YAML ordered map support.  #2665 [Manuel Holtgrewe, nfbuckley]

0
@@ -20,7 +20,13 @@ module ActiveRecord
0
       super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' on the polymorphic object '#{source_reflection.class_name}##{source_reflection.name}'.")
0
     end
0
   end
0
-
0
+  
0
+  class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError #:nodoc:
0
+    def initialize(owner_class_name, reflection, source_reflection)
0
+      super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic.  Try removing :source_type on your association.")
0
+    end
0
+  end
0
+  
0
   class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError #:nodoc:
0
     def initialize(reflection)
0
       through_reflection      = reflection.through_reflection
0
@@ -529,6 +535,8 @@ module ActiveRecord
0
       # * <tt>:source</tt>: Specifies the source association name used by <tt>has_many :through</tt> queries.  Only use it if the name cannot be 
0
       #   inferred from the association.  <tt>has_many :subscribers, :through => :subscriptions</tt> will look for either +:subscribers+ or
0
       #   +:subscriber+ on +Subscription+, unless a +:source+ is given.
0
+      # * <tt>:source_type</tt>: Specifies type of the source association used by <tt>has_many :through</tt> queries where the source association
0
+      #   is a polymorphic belongs_to.
0
       # * <tt>:uniq</tt> - if set to true, duplicates will be omitted from the collection. Useful in conjunction with :through.
0
       #
0
       # Option examples:
0
@@ -1087,7 +1095,7 @@ module ActiveRecord
0
             :class_name, :table_name, :foreign_key,
0
             :exclusively_dependent, :dependent,
0
             :select, :conditions, :include, :order, :group, :limit, :offset,
0
-            :as, :through, :source,
0
+            :as, :through, :source, :source_type,
0
             :uniq,
0
             :finder_sql, :counter_sql, 
0
             :before_add, :after_add, :before_remove, :after_remove, 
0
@@ -1491,57 +1499,65 @@ module ActiveRecord
0
                   case
0
                     when reflection.macro == :has_many && reflection.options[:through]
0
                       through_conditions = through_reflection.options[:conditions] ? "AND #{interpolate_sql(sanitize_sql(through_reflection.options[:conditions]))}" : ''
0
+
0
+                      jt_foreign_key = jt_as_extra = jt_source_extra = jt_sti_extra = nil
0
+                      first_key = second_key = as_extra = nil
0
+                      
0
                       if through_reflection.options[:as] # has_many :through against a polymorphic join
0
-                        polymorphic_foreign_key  = through_reflection.options[:as].to_s + '_id'
0
-                        polymorphic_foreign_type = through_reflection.options[:as].to_s + '_type'
0
-
0
-                        " LEFT OUTER JOIN %s ON (%s.%s = %s.%s AND %s.%s = %s) "  % [
0
-                          table_alias_for(through_reflection.klass.table_name, aliased_join_table_name),
0
-                          aliased_join_table_name, polymorphic_foreign_key,
0
-                          parent.aliased_table_name, parent.primary_key,
0
-                          aliased_join_table_name, polymorphic_foreign_type, klass.quote_value(parent.active_record.base_class.name)] +
0
-                        " LEFT OUTER JOIN %s ON %s.%s = %s.%s " % [table_name_and_alias,
0
-                          aliased_table_name, primary_key, aliased_join_table_name, options[:foreign_key] || reflection.klass.to_s.classify.foreign_key
0
+                        jt_foreign_key = through_reflection.options[:as].to_s + '_id'
0
+                        jt_as_extra = " AND %s.%s = %s" % [
0
+                            aliased_join_table_name, reflection.active_record.connection.quote_column_name(through_reflection.options[:as].to_s + '_type'), 
0
+                            klass.quote_value(parent.active_record.base_class.name)
0
                         ]
0
                       else
0
-                        if source_reflection.macro == :has_many && source_reflection.options[:as]
0
-                          " LEFT OUTER JOIN %s ON %s.%s = %s.%s "  % [
0
-                            table_alias_for(through_reflection.klass.table_name, aliased_join_table_name), aliased_join_table_name,
0
-                            through_reflection.primary_key_name,
0
-                            parent.aliased_table_name, parent.primary_key] +
0
-                          " LEFT OUTER JOIN %s ON %s.%s = %s.%s AND %s.%s = %s " % [
0
-                            table_name_and_alias,
0
-                            aliased_table_name, "#{source_reflection.options[:as]}_id", 
0
-                            aliased_join_table_name, options[:foreign_key] || primary_key,
0
-                            aliased_table_name, "#{source_reflection.options[:as]}_type", 
0
+                        jt_foreign_key = through_reflection.primary_key_name
0
+                      end
0
+                      
0
+                      case source_reflection.macro
0
+                      when :has_many
0
+                        if source_reflection.options[:as]
0
+                          first_key   = "#{source_reflection.options[:as]}_id"
0
+                          second_key  = options[:foreign_key] || primary_key
0
+                          as_extra    = " AND %s.%s = %s" % [
0
+                            aliased_table_name, reflection.active_record.connection.quote_column_name("#{source_reflection.options[:as]}_type"), 
0
                             klass.quote_value(source_reflection.active_record.base_class.name)
0
                           ]
0
                         else
0
-                          case source_reflection.macro
0
-                            when :belongs_to
0
-                              first_key  = primary_key
0
-                              second_key = source_reflection.options[:foreign_key] || klass.to_s.classify.foreign_key
0
-                              extra      = nil
0
-                            when :has_many
0
-                              first_key  = through_reflection.klass.base_class.to_s.classify.foreign_key
0
-                              second_key = options[:foreign_key] || primary_key
0
-                              extra      = through_reflection.klass.descends_from_active_record? ? nil :
0
-                                " AND %s.%s = %s" % [
0
-                                  aliased_join_table_name,
0
-                                  reflection.active_record.connection.quote_column_name(through_reflection.active_record.inheritance_column),
0
-                                  through_reflection.klass.quote_value(through_reflection.klass.name.demodulize)]
0
-                          end
0
-                          " LEFT OUTER JOIN %s ON (%s.%s = %s.%s%s) "  % [
0
-                            table_alias_for(through_reflection.klass.table_name, aliased_join_table_name), 
0
-                            aliased_join_table_name, through_reflection.primary_key_name,
0
-                            parent.aliased_table_name, parent.primary_key, extra] +
0
-                          " LEFT OUTER JOIN %s ON (%s.%s = %s.%s) " % [
0
-                            table_name_and_alias,
0
-                            aliased_table_name, first_key, 
0
-                            aliased_join_table_name, second_key
0
+                          first_key   = through_reflection.klass.base_class.to_s.classify.foreign_key
0
+                          second_key  = options[:foreign_key] || primary_key
0
+                        end
0
+                        
0
+                        unless through_reflection.klass.descends_from_active_record?
0
+                          jt_sti_extra = " AND %s.%s = %s" % [
0
+                            aliased_join_table_name,
0
+                            reflection.active_record.connection.quote_column_name(through_reflection.active_record.inheritance_column),
0
+                            through_reflection.klass.quote_value(through_reflection.klass.name.demodulize)]
0
+                        end
0
+                      when :belongs_to
0
+                        first_key = primary_key
0
+                        if reflection.options[:source_type]
0
+                          second_key = source_reflection.association_foreign_key
0
+                          jt_source_extra = " AND %s.%s = %s" % [
0
+                              aliased_join_table_name, reflection.active_record.connection.quote_column_name(reflection.source_reflection.options[:foreign_type]),
0
+                              klass.quote_value(reflection.options[:source_type])
0
                           ]
0
+                        else
0
+                          second_key = source_reflection.options[:foreign_key] || klass.to_s.classify.foreign_key
0
                         end
0
                       end
0
+                      
0
+                      " LEFT OUTER JOIN %s ON (%s.%s = %s.%s%s%s%s) " % [
0
+                        table_alias_for(through_reflection.klass.table_name, aliased_join_table_name),
0
+                        parent.aliased_table_name, reflection.active_record.connection.quote_column_name(parent.primary_key),
0
+                        aliased_join_table_name, reflection.active_record.connection.quote_column_name(jt_foreign_key), 
0
+                        jt_as_extra, jt_source_extra, jt_sti_extra
0
+                      ] +
0
+                      " LEFT OUTER JOIN %s ON (%s.%s = %s.%s%s) " % [
0
+                        table_name_and_alias, 
0
+                        aliased_table_name, reflection.active_record.connection.quote_column_name(first_key),
0
+                        aliased_join_table_name, reflection.active_record.connection.quote_column_name(second_key),
0
+                        as_extra
0
+                      ]
0
                     
0
                     when reflection.macro == :has_many && reflection.options[:as]
0
                       " LEFT OUTER JOIN %s ON %s.%s = %s.%s AND %s.%s = %s" % [
0
@@ -1588,6 +1604,7 @@ module ActiveRecord
0
             end
0
             
0
             protected
0
+
0
               def pluralize(table_name)
0
                 ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name
0
               end

0
@@ -138,7 +138,11 @@ module ActiveRecord
0
 
0
         # Construct attributes for :through pointing to owner and associate.
0
         def construct_join_attributes(associate)
0
-          construct_owner_attributes(@reflection.through_reflection).merge(@reflection.source_reflection.primary_key_name => associate.id)
0
+          returning construct_owner_attributes(@reflection.through_reflection).merge(@reflection.source_reflection.primary_key_name => associate.id) do |join_attributes|
0
+            if @reflection.options[:source_type]
0
+              join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name.to_s)
0
+            end
0
+          end
0
         end
0
 
0
         # Associate attributes pointing to owner, quoted.
0
@@ -176,6 +180,12 @@ module ActiveRecord
0
           if @reflection.through_reflection.options[:as] || @reflection.source_reflection.macro == :belongs_to
0
             reflection_primary_key = @reflection.klass.primary_key
0
             source_primary_key     = @reflection.source_reflection.primary_key_name
0
+            if @reflection.options[:source_type]
0
+              polymorphic_join = "AND %s.%s = %s" % [
0
+                @reflection.through_reflection.table_name, "#{@reflection.source_reflection.options[:foreign_type]}",
0
+                @owner.class.quote_value(@reflection.options[:source_type])
0
+              ]
0
+            end
0
           else
0
             reflection_primary_key = @reflection.source_reflection.primary_key_name
0
             source_primary_key     = @reflection.klass.primary_key

0
@@ -186,8 +186,12 @@ module ActiveRecord
0
           if source_reflection.nil?
0
             raise HasManyThroughSourceAssociationNotFoundError.new(self)
0
           end
0
+
0
+          if options[:source_type] && source_reflection.options[:polymorphic].nil?
0
+            raise HasManyThroughAssociationPointlessSourceTypeError.new(active_record.name, self, source_reflection)
0
+          end
0
           
0
-          if source_reflection.options[:polymorphic]
0
+          if source_reflection.options[:polymorphic] && options[:source_type].nil?
0
             raise HasManyThroughAssociationPolymorphicError.new(active_record.name, self, source_reflection)
0
           end
0
           
0
@@ -205,7 +209,7 @@ module ActiveRecord
0
             if options[:class_name]
0
               options[:class_name]
0
             elsif through_reflection # get the class_name of the belongs_to association of the through reflection
0
-              source_reflection.class_name
0
+              options[:source_type] || source_reflection.class_name
0
             else
0
               class_name = name.to_s.camelize
0
               class_name = class_name.singularize if [ :has_many, :has_and_belongs_to_many ].include?(macro)

0
@@ -300,6 +300,18 @@ class AssociationsJoinModelTest < Test::Unit::TestCase
0
       assert_equal [posts(:welcome), posts(:thinking)], tags(:general).taggings.find(:all, :include => :taggable)
0
     end
0
   end
0
+  
0
+  def test_has_many_polymorphic_with_source_type
0
+    assert_equal [posts(:welcome), posts(:thinking)], tags(:general).tagged_posts
0
+  end
0
+
0
+  def test_eager_has_many_polymorphic_with_source_type
0
+    tag_with_include = Tag.find(tags(:general).id, :include => :tagged_posts)
0
+    desired = [posts(:welcome), posts(:thinking)]
0
+    assert_no_queries do
0
+      assert_equal desired, tag_with_include.tagged_posts
0
+    end
0
+  end
0
 
0
   def test_has_many_through_has_many_find_all
0
     assert_equal comments(:greetings), authors(:david).comments.find(:all, :order => 'comments.id').first

0
@@ -2,4 +2,6 @@ class Tag < ActiveRecord::Base
0
   has_many :taggings
0
   has_many :taggables, :through => :taggings
0
   has_one  :tagging
0
+
0
+  has_many :tagged_posts, :through => :taggings, :source => :taggable, :source_type => 'Post'
0
 end
0
\ No newline at end of file