- Fixed an 0.9 regression where the automatic aliasing applied by

:class:`.Query` and in other situations where selects or joins
were aliased (such as joined table inheritance) could fail if a
user-defined :class:`.Column` subclass were used in the expression.
In this case, the subclass would fail to propagate ORM-specific
"annotations" along needed by the adaptation.  The "expression
annotations" system has been corrected to account for this case.
[ticket:2918]

2 files changed, 11 insertions, 3 deletions

diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 6bd465e9c..23fe9315a 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -229,7 +229,6 @@ class Query(object):
         have been applied within this query."""
 
         adapters = []
-
         # do we adapt all expression elements or only those
         # tagged as 'ORM' constructs ?
         orm_only = getattr(self, '_orm_only_adapt', orm_only)
diff --git a/lib/sqlalchemy/sql/annotation.py b/lib/sqlalchemy/sql/annotation.py
index b5b7849d2..11b066675 100644
--- a/lib/sqlalchemy/sql/annotation.py
+++ b/lib/sqlalchemy/sql/annotation.py
@@ -167,9 +167,18 @@ def _new_annotation_type(cls, base_cls):
         return cls
     elif cls in annotated_classes:
         return annotated_classes[cls]
+
+    for super_ in cls.__mro__:
+        # check if an Annotated subclass more specific than
+        # the given base_cls is already registered, such
+        # as AnnotatedColumnElement.
+        if super_ in annotated_classes:
+            base_cls = annotated_classes[super_]
+            break
+
     annotated_classes[cls] = anno_cls = type(
-                                "Annotated%s" % cls.__name__,
-                                (base_cls, cls), {})
+                            "Annotated%s" % cls.__name__,
+                            (base_cls, cls), {})
     globals()["Annotated%s" % cls.__name__] = anno_cls
     return anno_cls