Remove :timestamp column type

The `:timestamp` type for columns is unused. All database adapters treat
them as the same database type. All code in `ActiveRecord` which changes
its behavior based on the column's type acts the same in both cases.
However, when the type is passed to code that checks for the `:datetime`
type, but not `:timestamp` (such as XML serialization), the result is
unexpected behavior.

Existing schema definitions will continue to work, and the `timestamp`
type is transparently aliased to `datetime`.

1 files changed, 2 insertions, 5 deletions

diff --git a/activerecord/test/cases/connection_adapters/type_lookup_test.rb b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
index a5b01260d3..18df30faf5 100644
--- a/activerecord/test/cases/connection_adapters/type_lookup_test.rb
+++ b/activerecord/test/cases/connection_adapters/type_lookup_test.rb
@@ -45,14 +45,11 @@ module ActiveRecord
         assert_lookup_type :time, 'TIME'
       end
 
-      def test_timestamp_types
-        assert_lookup_type :timestamp, 'timestamp'
-        assert_lookup_type :timestamp, 'TIMESTAMP'
-      end
-
       def test_datetime_types
         assert_lookup_type :datetime, 'datetime'
         assert_lookup_type :datetime, 'DATETIME'
+        assert_lookup_type :datetime, 'timestamp'
+        assert_lookup_type :datetime, 'TIMESTAMP'
       end
 
       def test_decimal_types