dev3149

2 files changed, 25 insertions, 11 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__:
diff --git a/lib/sqlalchemy/ext/declarative/base.py b/lib/sqlalchemy/ext/declarative/base.py
index cee22637d..d17338bcb 100644
--- a/lib/sqlalchemy/ext/declarative/base.py
+++ b/lib/sqlalchemy/ext/declarative/base.py
@@ -132,11 +132,8 @@ def _as_declarative(cls, classname, dict_):
                         "column_property(), relationship(), etc.) must "
                         "be declared as @declared_attr callables "
                         "on declarative mixin classes.")
-                elif isinstance(obj, _memoized_declared_attr): # and \
-                    if obj._cascading:
-                        dict_[name] = ret = obj.__get__(obj, cls)
-                    else:
-                        dict_[name] = ret = getattr(cls, name)
+                elif isinstance(obj, _memoized_declared_attr):
+                    dict_[name] = ret = obj.resolve_early(cls, name)
                     if isinstance(ret, (Column, MapperProperty)) and \
                             ret.doc is None:
                         ret.doc = obj.__doc__
@@ -166,7 +163,7 @@ def _as_declarative(cls, classname, dict_):
 
         value = dict_[k]
         if isinstance(value, declarative_props):
-            if value.defer_defer_defer:
+            if value.should_resolve_late:
                 add_later[k] = value
             else:
                 value = getattr(cls, k)
@@ -426,7 +423,7 @@ class _MapperConfig(object):
             **mapper_args
         )
         for k, v in self.add_later.items():
-            setattr(self.cls, k, v.fget(self.cls))
+            setattr(self.cls, k, v.resolve_late(self.cls, k))
 
 
 class _DeferredMapperConfig(_MapperConfig):