- The :class:`.TypeDecorator` type extender will now work in conjunction

with a :class:`.SchemaType` implementation, typically :class:`.Enum`
or :class:`.Boolean` with regards to ensuring that the per-table
events are propagated from the implementation type to the outer type.
These events are used
to ensure that the constraints or Postgresql types (e.g. ENUM)
are correctly created (and possibly dropped) along with the parent
table.
fixes #2919

1 files changed, 14 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index b9826e585..f5ab1a8d3 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -13,6 +13,7 @@
 from .. import exc, util
 from . import operators
 from .visitors import Visitable, VisitableType
+from .base import SchemaEventTarget
 
 # these are back-assigned by sqltypes.
 BOOLEANTYPE = None
@@ -592,7 +593,7 @@ class UserDefinedType(util.with_metaclass(VisitableCheckKWArg, TypeEngine)):
         return self
 
 
-class TypeDecorator(TypeEngine):
+class TypeDecorator(SchemaEventTarget, TypeEngine):
     """Allows the creation of types which add additional functionality
     to an existing type.
 
@@ -772,6 +773,18 @@ class TypeDecorator(TypeEngine):
         """
         return self.impl._type_affinity
 
+    def _set_parent(self, column):
+        """Support SchemaEentTarget"""
+
+        if isinstance(self.impl, SchemaEventTarget):
+            self.impl._set_parent(column)
+
+    def _set_parent_with_dispatch(self, parent):
+        """Support SchemaEentTarget"""
+
+        if isinstance(self.impl, SchemaEventTarget):
+            self.impl._set_parent_with_dispatch(parent)
+
     def type_engine(self, dialect):
         """Return a dialect-specific :class:`.TypeEngine` instance
         for this :class:`.TypeDecorator`.