Check for hybrid's attribute name and support no name

Fixed regression where the ORM compilation scheme would assume the function
name of a hybrid property would be the same as the attribute name in such a
way that an ``AttributeError`` would be raised, when it would attempt to
determine the correct name for each element in a result tuple. A similar
issue exists in 1.3 but only impacts the names of tuple rows. The fix here
adds a check that the hybrid's function name is actually present in the
``__dict__`` of the class or its superclasses before assigning this name;
otherwise, the hybrid is considered to be "unnamed" and ORM result tuples
will use the naming scheme of the underlying expression.

Fixes: #6215
Change-Id: I584c0c05efec957f4dcaccf5df371399a57dffe9

1 files changed, 15 insertions, 3 deletions

diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index 610ee2726..d1ed17f1a 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -54,6 +54,13 @@ from ..sql import traversals
 from ..sql import visitors
 
 
+class NoKey(str):
+    pass
+
+
+NO_KEY = NoKey("no name")
+
+
 @inspection._self_inspects
 class QueryableAttribute(
     interfaces._MappedAttribute,
@@ -214,10 +221,15 @@ class QueryableAttribute(
         subclass representing a column expression.
 
         """
+        if self.key is NO_KEY:
+            annotations = {"entity_namespace": self._entity_namespace}
+        else:
+            annotations = {
+                "proxy_key": self.key,
+                "entity_namespace": self._entity_namespace,
+            }
 
-        return self.comparator.__clause_element__()._annotate(
-            {"proxy_key": self.key, "entity_namespace": self._entity_namespace}
-        )
+        return self.comparator.__clause_element__()._annotate(annotations)
 
     @property
     def _entity_namespace(self):