From 8e297afa8ddd66d5d7317a1b965a8919adb8f1aa Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Tue, 30 May 2023 14:54:42 -0400
Subject: [PATCH] use internal declarative creator for DeclarativeBaseNoMeta

Fixed issue where :class:`.DeclarativeBaseNoMeta` declarative base class
would not function with non-mapped mixins or abstract classes, raising an
``AttributeError`` instead.

Fixes: #9862
Change-Id: I91cfe663530a2eb712004b9fb09d3f0cefcaeef5
---
 doc/build/changelog/unreleased_20/9862.rst |  7 ++++
 lib/sqlalchemy/orm/decl_api.py             |  2 +-
 test/orm/declarative/test_basic.py         | 48 ++++++++++++++++++++++
 3 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 doc/build/changelog/unreleased_20/9862.rst

diff --git a/doc/build/changelog/unreleased_20/9862.rst b/doc/build/changelog/unreleased_20/9862.rst
new file mode 100644
index 0000000000..efa6274a98
--- /dev/null
+++ b/doc/build/changelog/unreleased_20/9862.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, orm
+    :tickets: 9862
+
+    Fixed issue where :class:`.DeclarativeBaseNoMeta` declarative base class
+    would not function with non-mapped mixins or abstract classes, raising an
+    ``AttributeError`` instead.
diff --git a/lib/sqlalchemy/orm/decl_api.py b/lib/sqlalchemy/orm/decl_api.py
index cb25e34ca0..01b78aa99c 100644
--- a/lib/sqlalchemy/orm/decl_api.py
+++ b/lib/sqlalchemy/orm/decl_api.py
@@ -943,7 +943,7 @@ class DeclarativeBaseNoMeta(inspection.Inspectable[InstanceState[Any]]):
             _check_not_declarative(cls, DeclarativeBaseNoMeta)
             _setup_declarative_base(cls)
         else:
-            cls._sa_registry.map_declaratively(cls)
+            _as_declarative(cls._sa_registry, cls, cls.__dict__)
 
 
 def add_mapped_attribute(
diff --git a/test/orm/declarative/test_basic.py b/test/orm/declarative/test_basic.py
index 3ad7db0799..a76e375b22 100644
--- a/test/orm/declarative/test_basic.py
+++ b/test/orm/declarative/test_basic.py
@@ -1151,6 +1151,54 @@ class DeclarativeMultiBaseTest(
         eq_(a1, Address(email="two"))
         eq_(a1.user, User(name="u1"))
 
+    @testing.variation("mora", ["mixin", "abstract"])
+    def test_abstract_and_or_mixin(self, mora):
+        if mora.abstract:
+
+            class Employee(Base):
+                __abstract__ = True
+
+                id = mapped_column(Integer, primary_key=True, sort_order=-1)
+
+            class Manager(Employee):
+                __tablename__ = "manager"
+                name = mapped_column(String(50))
+                manager_data = mapped_column(String(40))
+
+            class Engineer(Employee):
+                __tablename__ = "engineer"
+
+                name = mapped_column(String(50))
+                engineer_info = mapped_column(String(40))
+
+        elif mora.mixin:
+
+            class Mixin:
+                pass
+
+            class EmployeeMixin:
+                id = mapped_column(Integer, primary_key=True, sort_order=-1)
+
+            class Manager(EmployeeMixin, Base):
+                __tablename__ = "manager"
+                name = mapped_column(String(50))
+                manager_data = mapped_column(String(40))
+
+            class Engineer(EmployeeMixin, Base):
+                __tablename__ = "engineer"
+
+                name = mapped_column(String(50))
+                engineer_info = mapped_column(String(40))
+
+        else:
+            mora.fail()
+
+        self.assert_compile(
+            select(Engineer),
+            "SELECT engineer.id, engineer.name, engineer.engineer_info "
+            "FROM engineer",
+        )
+
     def test_back_populates_setup(self):
         class User(Base):
             __tablename__ = "users"
-- 
2.39.5