sqlalchemy: Use built-in declarative

sqlalchemy.ext.declarative was deprecated in sqlalchemy 1.4.0, due to
the built-in implementations[1].

[1] https://github.com/sqlalchemy/sqlalchemy/commit/450f5c0d6519a439f40

Change-Id: I56f95f90f53e880f73a08b7eaaf853b35601abe4

neutron_lib/db/model_base.py

@@ -13,7 +13,6 @@
 from oslo_db.sqlalchemy import models
 from oslo_utils import uuidutils
 import sqlalchemy as sa
-from sqlalchemy.ext import declarative
 from sqlalchemy import orm
 
 from neutron_lib.db import constants as db_const
@@ -32,7 +31,7 @@ class HasProject:
     def set_tenant_id(self, value):
         self.project_id = value
 
-    @declarative.declared_attr
+    @orm.declared_attr
     def tenant_id(cls):
         return orm.synonym(
             'project_id',
@@ -104,17 +103,11 @@ class _NeutronBase(models.ModelBase):
 
 class NeutronBaseV2(_NeutronBase):
 
-    @declarative.declared_attr
+    @orm.declared_attr
     def __tablename__(cls):
         # Use the pluralized name of the class as the table name.
         return cls.__name__.lower() + 's'
 
 
-try:
-    # SQLAlchemy 2.0
-    class BASEV2(orm.DeclarativeBase, NeutronBaseV2):
-        pass
-except AttributeError:
-    # SQLAlchemy < 2.0
-    BASEV2 = declarative.declarative_base(  # type: ignore[misc]
-        cls=NeutronBaseV2)
+class BASEV2(orm.DeclarativeBase, NeutronBaseV2):
+    pass

neutron_lib/db/standard_attr.py

@@ -16,8 +16,8 @@ from oslo_utils import timeutils
 import sqlalchemy as sa
 from sqlalchemy import event  # noqa
 from sqlalchemy.ext.associationproxy import association_proxy
-from sqlalchemy.ext import declarative
 from sqlalchemy.orm import attributes
+from sqlalchemy.orm import declared_attr
 from sqlalchemy.orm import session as se
 
 from neutron_lib._i18n import _
@@ -138,7 +138,7 @@ class HasStandardAttributes:
     def validate_tag_support(cls):
         return getattr(cls, 'tag_support', False)
 
-    @declarative.declared_attr
+    @declared_attr
     def standard_attr_id(cls):
         return sa.Column(
             sa.BigInteger().with_variant(sa.Integer(), 'sqlite'),
@@ -150,7 +150,7 @@ class HasStandardAttributes:
     # NOTE(kevinbenton): we have to disable the following pylint check because
     # it thinks we are overriding this method in the __init__ method.
     # pylint: disable=method-hidden
-    @declarative.declared_attr
+    @declared_attr
     def standard_attr(cls):
         return sa.orm.relationship(StandardAttribute,
                                    lazy='joined',
@@ -174,15 +174,15 @@ class HasStandardAttributes:
         self.standard_attr = StandardAttribute(
             resource_type=self.__tablename__, **standard_attr_kwargs)
 
-    @declarative.declared_attr
+    @declared_attr
     def description(cls):
         return association_proxy('standard_attr', 'description')
 
-    @declarative.declared_attr
+    @declared_attr
     def created_at(cls):
         return association_proxy('standard_attr', 'created_at')
 
-    @declarative.declared_attr
+    @declared_attr
     def updated_at(cls):
         return association_proxy('standard_attr', 'updated_at')
 
@@ -193,7 +193,7 @@ class HasStandardAttributes:
         new_dict.pop('updated_at', None)
         super().update(new_dict)
 
-    @declarative.declared_attr
+    @declared_attr
     def revision_number(cls):
         return association_proxy('standard_attr', 'revision_number')
 

neutron_lib/tests/unit/db/test_standard_attr.py

@@ -14,7 +14,6 @@
 
 import gc
 
-from sqlalchemy.ext import declarative
 from sqlalchemy import orm
 import testtools
 
@@ -30,17 +29,11 @@ class StandardAttrTestCase(base.BaseTestCase):
     def _make_decl_base(self):
         # construct a new base so we don't interfere with the main
         # base used in the sql test fixtures
-        try:
-            # SQLAlchemy 2.0
-            class BaseV2(orm.DeclarativeBase,
-                         standard_attr.model_base.NeutronBaseV2):
-                pass
+        class BaseV2(orm.DeclarativeBase,
+                     standard_attr.model_base.NeutronBaseV2):
+            pass
 
-            return BaseV2
-        except AttributeError:
-            # SQLAlchemy < 2.0
-            return declarative.declarative_base(
-                cls=standard_attr.model_base.NeutronBaseV2)
+        return BaseV2
 
     def test_standard_attr_resource_model_map(self):
         rs_map = standard_attr.get_standard_attr_resource_model_map()

neutron_lib/tests/unit/db/test_utils.py

@@ -15,7 +15,6 @@ from unittest import mock
 from oslo_config import cfg
 from oslo_db.sqlalchemy import models
 import sqlalchemy as sa
-from sqlalchemy.ext import declarative
 from sqlalchemy import orm
 
 from neutron_lib.api import attributes
@@ -26,14 +25,8 @@ from neutron_lib import exceptions as n_exc
 from neutron_lib.tests import _base as base
 
 
-try:
-    # SQLAlchemy 2.0
-    class ModelBaseV2(orm.DeclarativeBase, models.ModelBase):
-        pass
-except AttributeError:
-    # SQLAlchemy < 2.0
-    ModelBaseV2 = declarative.declarative_base(  # type: ignore[misc]
-        cls=models.ModelBase)
+class ModelBaseV2(orm.DeclarativeBase, models.ModelBase):
+    pass
 
 
 class FakePort(ModelBaseV2):