The type_cast_calculated_value method will trust DB types before cast…

…ing to a BigDecimal.

[#6365 state:committed]

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

activerecord/lib/active_record/relation/calculations.rb

@@ -276,7 +276,7 @@ def type_cast_calculated_value(value, column, operation = nil)
       case operation
         when 'count'   then value.to_i
         when 'sum'     then type_cast_using_column(value || '0', column)
-        when 'average' then value.try(:to_d)
+        when 'average' then value.respond_to?(:to_d) ? value.to_d : value
         else type_cast_using_column(value, column)
       end
     end

activerecord/test/cases/calculations_test.rb

@@ -28,6 +28,12 @@ def test_should_return_decimal_average_of_integer_field
     assert_equal 3.5, value
   end
 
+  def test_should_return_integer_average_if_db_returns_such
+    Account.connection.stubs :select_value => 3
+    value = Account.average(:id)
+    assert_equal 3, value
+  end
+
   def test_should_return_nil_as_average
     assert_nil NumericData.average(:bank_balance)
   end