Consult plugin_subject for non-ORM enabled stmts in get_bind()

Enhanced the bind resolution rules for :meth:`_orm.Session.execute` so that
when a non-ORM statement such as an :func:`_sql.insert` construct
nonetheless is built against ORM objects, to the greatest degree possible
the ORM entity will be used to resolve the bind, such as for a
:class:`_orm.Session` that has a bind map set up on a common superclass
without specific mappers or tables named in the map.

Fixes: #6484
Change-Id: Iaa711b7f2c7451377b50af63029f37c4375a6f7e

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py
index cdf3a1585..e4a9b9046 100644
--- a/lib/sqlalchemy/orm/session.py
+++ b/lib/sqlalchemy/orm/session.py
@@ -1997,6 +1997,15 @@ class Session(_SessionClassMethods):
                     clause = mapper.persist_selectable
 
             if clause is not None:
+                plugin_subject = clause._propagate_attrs.get(
+                    "plugin_subject", None
+                )
+
+                if plugin_subject is not None:
+                    for cls in plugin_subject.mapper.class_.__mro__:
+                        if cls in self.__binds:
+                            return self.__binds[cls]
+
                 for obj in visitors.iterate(clause):
                     if obj in self.__binds:
                         return self.__binds[obj]