implement attributes.Proxy._clone()

Fixed issue where the internal cloning used by the
:meth:`_orm.PropComparator.any` method on a :func:`_orm.relationship` in
the case where the related class also makes use of ORM polymorphic loading,
would fail if a hybrid property on the related, polymorphic class were used
within the criteria for the ``any()`` operation.

Fixes: #7425
Change-Id: I5f4f4ec5fab17df228bc6e3de412d24114b20600

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index b66d55250..bf8d69b4e 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -571,6 +571,16 @@ def create_proxied_attribute(descriptor):
                 adapt_to_entity,
             )
 
+        def _clone(self, **kw):
+            return self.__class__(
+                self.class_,
+                self.key,
+                self.descriptor,
+                self._comparator,
+                adapt_to_entity=self._adapt_to_entity,
+                original_property=self.original_property,
+            )
+
         def __get__(self, instance, owner):
             retval = self.descriptor.__get__(instance, owner)
             # detect if this is a plain Python @property, which just returns