- SchemaItem, SchemaType now descend from common type

SchemaEventTarget, which supplies dispatch
- the dispatch now provides before_parent_attach(),
after_parent_attach(), events which generally bound the _set_parent()
event. [ticket:2037]
- the _on_table_attach mechanism now usually uses the
event dispatch
- fixed class-level event dispatch to propagate to all subclasses, not just
immediate subclasses
- fixed class-level event unpickling to handle more involved
inheritance hierarchies, needed by the new schema event dispatch.
- ForeignKeyConstraint doesn't re-call the column attach event
on ForeignKey objects that are already associated with the correct
Column
- we still need that ImportError on mysqldb CLIENT FLAGS to support
mock DBAPIs

1 files changed, 13 insertions, 3 deletions

diff --git a/lib/sqlalchemy/event.py b/lib/sqlalchemy/event.py
index 66b7e2d1b..0fcc8ef49 100644
--- a/lib/sqlalchemy/event.py
+++ b/lib/sqlalchemy/event.py
@@ -48,7 +48,11 @@ class _UnpickleDispatch(object):
 
     """
     def __call__(self, _parent_cls):
-        return _parent_cls.__dict__['dispatch'].dispatch_cls(_parent_cls)
+        for cls in _parent_cls.__mro__:
+            if 'dispatch' in cls.__dict__:
+                return cls.__dict__['dispatch'].dispatch_cls(_parent_cls)
+        else:
+            raise AttributeError("No class with a 'dispatch' member present.")
 
 class _Dispatch(object):
     """Mirror the event listening definitions of an Events class with 
@@ -167,11 +171,17 @@ class _DispatchDescriptor(object):
         assert isinstance(target, type), \
                 "Class-level Event targets must be classes."
 
-        for cls in [target] + target.__subclasses__():
+        stack = [target]
+        while stack:
+            cls = stack.pop(0)
+            stack.extend(cls.__subclasses__())
             self._clslevel[cls].append(obj)
 
     def remove(self, obj, target):
-        for cls in [target] + target.__subclasses__():
+        stack = [target]
+        while stack:
+            cls = stack.pop(0)
+            stack.extend(cls.__subclasses__())
             self._clslevel[cls].remove(obj)
 
     def clear(self):