Warn when trying to execute a query object with a session.

Passing a :class:`.Query` object to :meth:`_orm.Session.execute` is not
the intended use of this object, and will now raise a deprecation warning.

Fixes: #6284
Change-Id: I30a406d5a72335f9405f10f0a2030a32ccda41b9

1 files changed, 22 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/coercions.py b/lib/sqlalchemy/sql/coercions.py
index dce329352..f888bad4c 100644
--- a/lib/sqlalchemy/sql/coercions.py
+++ b/lib/sqlalchemy/sql/coercions.py
@@ -191,7 +191,6 @@ def expect(
                 resolved = element
     else:
         resolved = element
-
     if (
         apply_propagate_attrs is not None
         and not apply_propagate_attrs._propagate_attrs
@@ -843,6 +842,28 @@ class ReturnsRowsImpl(RoleImpl):
 class StatementImpl(_CoerceLiterals, RoleImpl):
     __slots__ = ()
 
+    def _post_coercion(self, resolved, original_element, argname=None, **kw):
+        if resolved is not original_element and not isinstance(
+            original_element, util.string_types
+        ):
+            # use same method as Connection uses; this will later raise
+            # ObjectNotExecutableError
+            try:
+                original_element._execute_on_connection
+            except AttributeError:
+                util.warn_deprecated(
+                    "Object %r should not be used directly in a SQL statement "
+                    "context, such as passing to methods such as "
+                    "session.execute().  This usage will be disallowed in a "
+                    "future release.  "
+                    "Please use Core select() / update() / delete() etc. "
+                    "with Session.execute() and other statement execution "
+                    "methods." % original_element,
+                    "1.4",
+                )
+
+        return resolved
+
     def _implicit_coercions(
         self, original_element, resolved, argname=None, **kw
     ):