[6.0.x] Fixed #36843, #36793 -- Reverted "Fixed #27489 -- Renamed permissions upon model renaming in migrations."

This reverts commits f02b49d2f3bf84f5225de920ca510149f1f9f1da and 6e89271a8507fe272d11814975500a1b40303a04.

Backport of 030c63d329c4814da221528e823a4aaaaa40e4f1 from main.

7 files changed, 12 insertions, 313 deletions

diff --git a/django/contrib/auth/apps.py b/django/contrib/auth/apps.py
index eeba5b7e13..ad6f816809 100644
--- a/django/contrib/auth/apps.py
+++ b/django/contrib/auth/apps.py
@@ -1,12 +1,12 @@
 from django.apps import AppConfig
 from django.core import checks
 from django.db.models.query_utils import DeferredAttribute
-from django.db.models.signals import post_migrate, pre_migrate
+from django.db.models.signals import post_migrate
 from django.utils.translation import gettext_lazy as _
 
 from . import get_user_model
 from .checks import check_middleware, check_models_permissions, check_user_model
-from .management import create_permissions, rename_permissions
+from .management import create_permissions
 from .signals import user_logged_in
 
 
@@ -20,11 +20,6 @@ class AuthConfig(AppConfig):
             create_permissions,
             dispatch_uid="django.contrib.auth.management.create_permissions",
         )
-        pre_migrate.connect(
-            rename_permissions,
-            dispatch_uid="django.contrib.auth.management.rename_permissions",
-        )
-
         last_login_field = getattr(get_user_model(), "last_login", None)
         # Register the handler only if UserModel.last_login is a field.
         if isinstance(last_login_field, DeferredAttribute):
diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index 21d357e32b..e816357b2b 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -9,9 +9,7 @@ from django.apps import apps as global_apps
 from django.contrib.auth import get_permission_codename
 from django.contrib.contenttypes.management import create_contenttypes
 from django.core import exceptions
-from django.db import DEFAULT_DB_ALIAS, migrations, router, transaction
-from django.db.utils import IntegrityError
-from django.utils.text import camel_case_to_spaces
+from django.db import DEFAULT_DB_ALIAS, router
 
 
 def _get_all_permissions(opts):
@@ -110,84 +108,6 @@ def create_permissions(
             print("Adding permission '%s'" % perm)
 
 
-class RenamePermission(migrations.RunPython):
-    def __init__(self, app_label, old_model, new_model):
-        self.app_label = app_label
-        self.old_model = old_model
-        self.new_model = new_model
-        super(RenamePermission, self).__init__(
-            self.rename_forward, self.rename_backward
-        )
-
-    def _rename(self, apps, schema_editor, old_model, new_model):
-        ContentType = apps.get_model("contenttypes", "ContentType")
-        # Use the live Permission model instead of the frozen one, since frozen
-        # models do not retain foreign key constraints.
-        from django.contrib.auth.models import Permission
-
-        db = schema_editor.connection.alias
-        ctypes = ContentType.objects.using(db).filter(
-            app_label=self.app_label, model__icontains=old_model.lower()
-        )
-        for permission in Permission.objects.using(db).filter(
-            content_type_id__in=ctypes.values("id")
-        ):
-            prefix = permission.codename.split("_")[0]
-            default_verbose_name = camel_case_to_spaces(new_model)
-
-            new_codename = f"{prefix}_{new_model.lower()}"
-            new_name = f"Can {prefix} {default_verbose_name}"
-
-            if permission.codename != new_codename or permission.name != new_name:
-                permission.codename = new_codename
-                permission.name = new_name
-                try:
-                    with transaction.atomic(using=db):
-                        permission.save(update_fields={"name", "codename"})
-                except IntegrityError:
-                    pass
-
-    def rename_forward(self, apps, schema_editor):
-        self._rename(apps, schema_editor, self.old_model, self.new_model)
-
-    def rename_backward(self, apps, schema_editor):
-        self._rename(apps, schema_editor, self.new_model, self.old_model)
-
-
-def rename_permissions(
-    plan,
-    verbosity=2,
-    interactive=True,
-    using=DEFAULT_DB_ALIAS,
-    apps=global_apps,
-    **kwargs,
-):
-    """
-    Insert a `RenamePermissionType` operation after every planned `RenameModel`
-    operation.
-    """
-    try:
-        Permission = apps.get_model("auth", "Permission")
-    except LookupError:
-        return
-    else:
-        if not router.allow_migrate_model(using, Permission):
-            return
-
-    for migration, backward in plan:
-        inserts = []
-        for index, operation in enumerate(migration.operations):
-            if isinstance(operation, migrations.RenameModel):
-                operation = RenamePermission(
-                    migration.app_label,
-                    operation.old_name,
-                    operation.new_name,
-                )
-                inserts.append((index + 1, operation))
-        for inserted, (index, operation) in enumerate(inserts):
-            migration.operations.insert(inserted + index, operation)
-
-
 def get_system_username():
     """
     Return the current system user's username, or an empty string if the
diff --git a/docs/releases/6.0.1.txt b/docs/releases/6.0.1.txt
index a84b1ba6ef..499378cda7 100644
--- a/docs/releases/6.0.1.txt
+++ b/docs/releases/6.0.1.txt
@@ -42,3 +42,10 @@ Bugfixes
 * Fixed a regression in Django 6.0 where the :attr:`.Widget.use_fieldset`
   attribute of :class:`~django.forms.ClearableFileInput` was flipped
   from ``False`` to ``True`` (:ticket:`36829`).
+
+* Reverted an undocumented optimization in Django 6.0 that modified permission
+  :attr:`~django.contrib.auth.models.Permission.name` and
+  :attr:`~django.contrib.auth.models.Permission.codename` values when renaming
+  models via a migration. This change could affect unrelated
+  :class:`~django.contrib.auth.models.Permission` objects (:ticket:`36843`) and
+  did not report conflicts (:ticket:`36793`).
diff --git a/tests/auth_tests/operations_migrations/0001_initial.py b/tests/auth_tests/operations_migrations/0001_initial.py
deleted file mode 100644
index 49a475653c..0000000000
--- a/tests/auth_tests/operations_migrations/0001_initial.py
+++ /dev/null
@@ -1,14 +0,0 @@
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-    initial = True
-
-    operations = [
-        migrations.CreateModel(
-            name="OldModel",
-            fields=[
-                ("id", models.AutoField(primary_key=True)),
-            ],
-        ),
-    ]
diff --git a/tests/auth_tests/operations_migrations/0002_rename_oldmodel_to_newmodel.py b/tests/auth_tests/operations_migrations/0002_rename_oldmodel_to_newmodel.py
deleted file mode 100644
index a23761e8fd..0000000000
--- a/tests/auth_tests/operations_migrations/0002_rename_oldmodel_to_newmodel.py
+++ /dev/null
@@ -1,14 +0,0 @@
-from django.db import migrations
-
-
-class Migration(migrations.Migration):
-    dependencies = [
-        ("auth_tests", "0001_initial"),
-    ]
-
-    operations = [
-        migrations.RenameModel(
-            old_name="OldModel",
-            new_name="NewModel",
-        ),
-    ]
diff --git a/tests/auth_tests/operations_migrations/__init__.py b/tests/auth_tests/operations_migrations/__init__.py
deleted file mode 100644
index e69de29bb2..0000000000
--- a/tests/auth_tests/operations_migrations/__init__.py
+++ /dev/null
diff --git a/tests/auth_tests/test_management.py b/tests/auth_tests/test_management.py
index 46fe310db2..0701ac2d68 100644
--- a/tests/auth_tests/test_management.py
+++ b/tests/auth_tests/test_management.py
@@ -7,21 +7,15 @@ from io import StringIO
 from unittest import mock
 
 from django.apps import apps
-from django.conf import settings
 from django.contrib.auth import get_permission_codename, management
-from django.contrib.auth.management import (
-    RenamePermission,
-    create_permissions,
-    get_default_username,
-)
+from django.contrib.auth.management import create_permissions, get_default_username
 from django.contrib.auth.management.commands import changepassword, createsuperuser
 from django.contrib.auth.models import Group, Permission, User
 from django.contrib.contenttypes.models import ContentType
 from django.core.management import call_command
 from django.core.management.base import CommandError
-from django.db import migrations, models
+from django.db import migrations
 from django.test import TestCase, override_settings
-from django.test.testcases import TransactionTestCase
 from django.utils.translation import gettext_lazy as _
 
 from .models import (
@@ -1534,195 +1528,6 @@ class CreatePermissionsTests(TestCase):
         )
 
 
-@override_settings(
-    MIGRATION_MODULES=dict(
-        settings.MIGRATION_MODULES,
-        auth_tests="auth_tests.operations_migrations",
-    ),
-)
-class PermissionRenameOperationsTests(TransactionTestCase):
-    available_apps = [
-        "django.contrib.contenttypes",
-        "django.contrib.auth",
-        "auth_tests",
-    ]
-    databases = {"default", "other"}
-
-    def setUp(self):
-        app_config = apps.get_app_config("auth_tests")
-        models.signals.post_migrate.connect(
-            self.assertOperationsInjected, sender=app_config
-        )
-        self.addCleanup(
-            models.signals.post_migrate.disconnect,
-            self.assertOperationsInjected,
-            sender=app_config,
-        )
-
-    def assertOperationsInjected(self, plan, **kwargs):
-        for migration, _backward in plan:
-            operations = iter(migration.operations)
-            for operation in operations:
-                if isinstance(operation, migrations.RenameModel):
-                    next_operation = next(operations)
-                    self.assertIsInstance(next_operation, RenamePermission)
-                    self.assertEqual(next_operation.app_label, migration.app_label)
-                    self.assertEqual(next_operation.old_model, operation.old_name)
-                    self.assertEqual(next_operation.new_model, operation.new_name)
-
-    def test_permission_rename(self):
-        ct = ContentType.objects.create(app_label="auth_tests", model="oldmodel")
-        actions = ["add", "change", "delete", "view"]
-        for action in actions:
-            Permission.objects.create(
-                codename=f"{action}_oldmodel",
-                name=f"Can {action} old model",
-                content_type=ct,
-            )
-
-        call_command("migrate", "auth_tests", verbosity=0)
-        for action in actions:
-            self.assertFalse(
-                Permission.objects.filter(codename=f"{action}_oldmodel").exists()
-            )
-            self.assertTrue(
-                Permission.objects.filter(codename=f"{action}_newmodel").exists()
-            )
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            "zero",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-
-        for action in actions:
-            self.assertTrue(
-                Permission.objects.filter(codename=f"{action}_oldmodel").exists()
-            )
-            self.assertFalse(
-                Permission.objects.filter(codename=f"{action}_newmodel").exists()
-            )
-
-    def test_permission_rename_other_db(self):
-        ct = ContentType.objects.using("default").create(
-            app_label="auth_tests", model="oldmodel"
-        )
-        permission = Permission.objects.using("default").create(
-            codename="add_oldmodel",
-            name="Can add old model",
-            content_type=ct,
-        )
-        # RenamePermission respects the database.
-        call_command("migrate", "auth_tests", verbosity=0, database="other")
-        permission.refresh_from_db()
-        self.assertEqual(permission.codename, "add_oldmodel")
-        self.assertFalse(
-            Permission.objects.using("other").filter(codename="add_oldmodel").exists()
-        )
-        self.assertTrue(
-            Permission.objects.using("other").filter(codename="add_newmodel").exists()
-        )
-
-    @mock.patch(
-        "django.db.router.allow_migrate_model",
-        return_value=False,
-    )
-    def test_rename_skipped_if_router_disallows(self, _):
-        ct = ContentType.objects.create(app_label="auth_tests", model="oldmodel")
-        Permission.objects.create(
-            codename="change_oldmodel",
-            name="Can change old model",
-            content_type=ct,
-        )
-        # The rename operation should not be there when disallowed by router.
-        app_config = apps.get_app_config("auth_tests")
-        models.signals.post_migrate.disconnect(
-            self.assertOperationsInjected, sender=app_config
-        )
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-        self.assertTrue(Permission.objects.filter(codename="change_oldmodel").exists())
-        self.assertFalse(Permission.objects.filter(codename="change_newmodel").exists())
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            "zero",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-
-    def test_rename_backward_does_nothing_if_no_permissions(self):
-        Permission.objects.filter(content_type__app_label="auth_tests").delete()
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            "zero",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-        self.assertFalse(
-            Permission.objects.filter(
-                codename__in=["change_oldmodel", "change_newmodel"]
-            ).exists()
-        )
-
-    def test_rename_permission_conflict(self):
-        ct = ContentType.objects.create(app_label="auth_tests", model="oldmodel")
-        Permission.objects.create(
-            codename="change_newmodel",
-            name="Can change new model",
-            content_type=ct,
-        )
-        Permission.objects.create(
-            codename="change_oldmodel",
-            name="Can change old model",
-            content_type=ct,
-        )
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-        self.assertTrue(
-            Permission.objects.filter(
-                codename="change_oldmodel",
-                name="Can change old model",
-            ).exists()
-        )
-        self.assertEqual(
-            Permission.objects.filter(
-                codename="change_newmodel",
-                name="Can change new model",
-            ).count(),
-            1,
-        )
-
-        call_command(
-            "migrate",
-            "auth_tests",
-            "zero",
-            database="default",
-            interactive=False,
-            verbosity=0,
-        )
-
-
 class DefaultDBRouter:
     """Route all writes to default."""