Fix :include of has_one with :primary_key option

activerecord/lib/active_record/association_preload.rb

@@ -195,7 +195,7 @@ def preload_has_and_belongs_to_many_association(records, reflection, preload_opt
 
       def preload_has_one_association(records, reflection, preload_options={})
         return if records.first.send("loaded_#{reflection.name}?")
-        id_to_record_map, ids = construct_id_map(records)
+        id_to_record_map, ids = construct_id_map(records, reflection.options[:primary_key])
         options = reflection.options
         records.each {|record| record.send("set_#{reflection.name}_target", nil)}
         if options[:through]

activerecord/test/cases/associations/eager_test.rb

@@ -803,4 +803,20 @@ def test_include_has_many_using_primary_key
     end
   end
 
+  def test_preload_has_one_using_primary_key
+    expected = Firm.find(:first).account_using_primary_key
+    firm = Firm.find :first, :include => :account_using_primary_key
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
+  def test_include_has_one_using_primary_key
+    expected = Firm.find(1).account_using_primary_key
+    firm = Firm.find(:all, :include => :account_using_primary_key, :order => 'accounts.id').detect {|f| f.id == 1}
+    assert_no_queries do
+      assert_equal expected, firm.account_using_primary_key
+    end
+  end
+
 end