Fixed #17962 -- Added ModelAdmin.get_deleted_objects().

AUTHORS

@@ -677,6 +677,7 @@ answer newbie questions, and generally made Django that much better:
     Raphaël Barrois <raphael.barrois@m4x.org>
     Raphael Michel <mail@raphaelmichel.de>
     Raúl Cumplido <raulcumplido@gmail.com>
+    Rebecca Smith <rebkwok@gmail.com>
     Remco Wendt <remco.wendt@gmail.com>
     Renaud Parent <renaud.parent@gmail.com>
     Renbi Yu <averybigant@gmail.com>

django/contrib/admin/actions.py

@@ -4,7 +4,7 @@ Built-in, globally-available admin actions.
 
 from django.contrib import messages
 from django.contrib.admin import helpers
-from django.contrib.admin.utils import get_deleted_objects, model_ngettext
+from django.contrib.admin.utils import model_ngettext
 from django.core.exceptions import PermissionDenied
 from django.template.response import TemplateResponse
 from django.utils.translation import gettext as _, gettext_lazy
@@ -29,9 +29,7 @@ def delete_selected(modeladmin, request, queryset):
 
     # Populate deletable_objects, a data structure of all related objects that
     # will also be deleted.
-    deletable_objects, model_count, perms_needed, protected = get_deleted_objects(
-        queryset, request.user, modeladmin.admin_site,
-    )
+    deletable_objects, model_count, perms_needed, protected = modeladmin.get_deleted_objects(queryset, request)
 
     # The user has already confirmed the deletion.
     # Do the deletion and return None to display the change list view again.

django/contrib/admin/options.py

@@ -1728,6 +1728,13 @@ class ModelAdmin(BaseModelAdmin):
             'admin/change_list.html'
         ], context)
 
+    def get_deleted_objects(self, objs, request):
+        """
+        Hook for customizing the delete process for the delete view and the
+        "delete selected" action.
+        """
+        return get_deleted_objects(objs, request.user, self.admin_site)
+
     @csrf_protect_m
     def delete_view(self, request, object_id, extra_context=None):
         with transaction.atomic(using=router.db_for_write(self.model)):
@@ -1752,9 +1759,7 @@ class ModelAdmin(BaseModelAdmin):
 
         # Populate deleted_objects, a data structure of all related objects that
         # will also be deleted.
-        deleted_objects, model_count, perms_needed, protected = get_deleted_objects(
-            [obj], request.user, self.admin_site,
-        )
+        deleted_objects, model_count, perms_needed, protected = self.get_deleted_objects([obj], request)
 
         if request.POST and not protected:  # The user has confirmed the deletion.
             if perms_needed:

docs/ref/contrib/admin/index.txt

@@ -1998,6 +1998,36 @@ templates used by the :class:`ModelAdmin` views:
         def get_changeform_initial_data(self, request):
             return {'name': 'custom_initial_value'}
 
+.. method:: ModelAdmin.get_deleted_objects(objs, request)
+
+    .. versionadded:: 2.1
+
+    A hook for customizing the deletion process of the :meth:`delete_view` and
+    the "delete selected" :doc:`action <actions>`.
+
+    The ``objs`` argument is a homogeneous iterable of objects (a ``QuerySet``
+    or a list of model instances) to be deleted, and ``request`` is the
+    :class:`~django.http.HttpRequest`.
+
+    This method must return a 4-tuple of
+    ``(deleted_objects, model_count, perms_needed, protected)``.
+
+    ``deleted_objects`` is a list of strings representing all the objects that
+    will be deleted. If there are any related objects to be deleted, the list
+    is nested and includes those related objects. The list is formatted in the
+    template using the :tfilter:`unordered_list` filter.
+
+    ``model_count`` is a dictionary mapping each model's
+    :attr:`~django.db.models.Options.verbose_name_plural` to the number of
+    objects that will be deleted.
+
+    ``perms_needed`` is a set of :attr:`~django.db.models.Options.verbose_name`\s
+    of the models that the user doesn't have permission to delete.
+
+    ``protected`` is a list of strings representing of all the protected
+    related objects that can't be deleted. The list is displayed in the
+    template.
+
 Other methods
 ~~~~~~~~~~~~~
 

docs/releases/2.1.txt

@@ -50,6 +50,9 @@ Minor features
 * The ``admin_order_field`` attribute for elements in
   :attr:`.ModelAdmin.list_display` may now be a query expression.
 
+* The new :meth:`.ModelAdmin.get_deleted_objects()` method allows customizing
+  the deletion process of the delete view and the "delete selected" action.
+
 :mod:`django.contrib.admindocs`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/admin_views/customadmin.py

@@ -46,9 +46,15 @@ class CustomPwdTemplateUserAdmin(UserAdmin):
     change_user_password_template = ['admin/auth/user/change_password.html']  # a list, to test fix for #18697
 
 
+class BookAdmin(admin.ModelAdmin):
+    def get_deleted_objects(self, objs, request):
+        return ['a deletable object'], {'books': 1}, set(), []
+
+
 site = Admin2(name="admin2")
 
 site.register(models.Article, base_admin.ArticleAdmin)
+site.register(models.Book, BookAdmin)
 site.register(models.Section, inlines=[base_admin.ArticleInline], search_fields=['name'])
 site.register(models.Thing, base_admin.ThingAdmin)
 site.register(models.Fabric, base_admin.FabricAdmin)

tests/admin_views/test_actions.py

@@ -12,7 +12,7 @@ from django.urls import reverse
 from .admin import SubscriberAdmin
 from .forms import MediaActionForm
 from .models import (
-    Actor, Answer, ExternalSubscriber, Question, Subscriber,
+    Actor, Answer, Book, ExternalSubscriber, Question, Subscriber,
     UnchangeableObject,
 )
 
@@ -153,6 +153,18 @@ class AdminActionsTest(TestCase):
         self.assertIs(SubscriberAdmin.overridden, True)
         self.assertEqual(Subscriber.objects.all().count(), 0)
 
+    def test_delete_selected_uses_get_deleted_objects(self):
+        """The delete_selected action uses ModelAdmin.get_deleted_objects()."""
+        book = Book.objects.create(name='Test Book')
+        data = {
+            ACTION_CHECKBOX_NAME: [book.pk],
+            'action': 'delete_selected',
+            'index': 0,
+        }
+        response = self.client.post(reverse('admin2:admin_views_book_changelist'), data)
+        # BookAdmin.get_deleted_objects() returns custom text.
+        self.assertContains(response, 'a deletable object')
+
     def test_custom_function_mail_action(self):
         """A custom action may be defined in a function."""
         action_data = {

tests/admin_views/tests.py

@@ -2357,6 +2357,13 @@ class AdminViewDeletedObjectsTest(TestCase):
         response = self.client.get(reverse('admin:admin_views_bookmark_delete', args=(bookmark.pk,)))
         self.assertContains(response, should_contain)
 
+    def test_delete_view_uses_get_deleted_objects(self):
+        """The delete view uses ModelAdmin.get_deleted_objects()."""
+        book = Book.objects.create(name='Test Book')
+        response = self.client.get(reverse('admin2:admin_views_book_delete', args=(book.pk,)))
+        # BookAdmin.get_deleted_objects() returns custom text.
+        self.assertContains(response, 'a deletable object')
+
 
 @override_settings(ROOT_URLCONF='admin_views.urls')
 class TestGenericRelations(TestCase):

tests/modeladmin/tests.py

@@ -666,6 +666,16 @@ class ModelAdminTests(TestCase):
         finally:
             self.site.unregister(Band)
 
+    def test_get_deleted_objects(self):
+        mock_request = MockRequest()
+        mock_request.user = User.objects.create_superuser(username='bob', email='bob@test.com', password='test')
+        ma = ModelAdmin(Band, self.site)
+        deletable_objects, model_count, perms_needed, protected = ma.get_deleted_objects([self.band], request)
+        self.assertEqual(deletable_objects, ['Band: The Doors'])
+        self.assertEqual(model_count, {'bands': 1})
+        self.assertEqual(perms_needed, set())
+        self.assertEqual(protected, [])
+
 
 class ModelAdminPermissionTests(SimpleTestCase):