dev3149

1 files changed, 21 insertions, 4 deletions

diff --git a/lib/sqlalchemy/ext/declarative/api.py b/lib/sqlalchemy/ext/declarative/api.py
index 251b06fed..d4450da58 100644
--- a/lib/sqlalchemy/ext/declarative/api.py
+++ b/lib/sqlalchemy/ext/declarative/api.py
@@ -172,7 +172,7 @@ class declared_attr(interfaces._MappedAttribute, property):
     def property(cls):
         return _declared_property
 
-    defer_defer_defer = False
+    should_resolve_late = False
 
 
 class _memoized_declared_attr(declared_attr):
@@ -182,7 +182,7 @@ class _memoized_declared_attr(declared_attr):
         self._cascading = cascading
 
     def __get__(desc, self, cls):
-        if desc.defer_defer_defer:
+        if desc.should_resolve_late:
             return desc
         elif cls in desc.reg:
             return desc.reg[cls]
@@ -190,6 +190,18 @@ class _memoized_declared_attr(declared_attr):
             desc.reg[cls] = obj = desc.fget(cls)
             return obj
 
+    def resolve_early(self, cls, name):
+        if not self._cascading:
+            return getattr(cls, name)
+        else:
+            return self.__get__(self, cls)
+
+    def resolve_late(self, cls, name):
+        if self.should_resolve_late:
+            return self.fget(cls)
+        else:
+            raise NotImplementedError()
+
     @classproperty
     def cascading(cls):
         return lambda decorated: cls(decorated, cascading=True)
@@ -200,8 +212,7 @@ class _declared_column(_memoized_declared_attr):
 
 
 class _declared_property(_memoized_declared_attr):
-    defer_defer_defer = True
-
+    should_resolve_late = True
 
 
 def declarative_base(bind=None, metadata=None, mapper=None, cls=object,
@@ -433,6 +444,12 @@ class AbstractConcreteBase(ConcreteBase):
         pjoin = cls._create_polymorphic_union(mappers)
         cls.__mapper__ = m = mapper(cls, pjoin, polymorphic_on=pjoin.c.type)
 
+        for base in cls.__mro__:
+            for name, obj in vars(base).items():
+                if isinstance(obj, _memoized_declared_attr) \
+                        and obj._cascading:
+                    m.add_property(name, obj.resolve_late(cls, name))
+
         for scls in cls.__subclasses__():
             sm = _mapper_or_none(scls)
             if sm.concrete and cls in scls.__bases__: