[5.2.x] Fixed #36217 -- Restored pre_save/post_save signal emission via LogEntry.save() for single-object deletion in the admin.

Regression in 40b3975e7d3e1464a733c69171ad7d38f8814280.

Thanks smiling-watermelon for the report.

Co-authored-by: Sarah Boyce <42296566+sarahboyce@users.noreply.github.com>

Backport of c09bceef68e5abb79accedd12dade16aa6577a09 from main.

django/contrib/admin/models.py

@@ -51,9 +51,7 @@ class LogEntryManager(models.Manager):
             change_message=change_message,
         )
 
-    def log_actions(
+    def log_actions(self, user_id, queryset, action_flag, change_message=""):
-        self, user_id, queryset, action_flag, change_message="", *, single_object=False
-    ):
         # RemovedInDjango60Warning.
         if type(self).log_action != LogEntryManager.log_action:
             warnings.warn(
@@ -93,7 +91,7 @@ class LogEntryManager(models.Manager):
             for obj in queryset
         ]
 
-        if single_object and log_entry_list:
+        if len(log_entry_list) == 1:
             instance = log_entry_list[0]
             instance.save()
             return instance

django/contrib/admin/options.py

@@ -955,7 +955,6 @@ class ModelAdmin(BaseModelAdmin):
             queryset=[obj],
             action_flag=ADDITION,
             change_message=message,
-            single_object=True,
         )
 
     def log_change(self, request, obj, message):
@@ -971,7 +970,6 @@ class ModelAdmin(BaseModelAdmin):
             queryset=[obj],
             action_flag=CHANGE,
             change_message=message,
-            single_object=True,
         )
 
     def log_deletion(self, request, obj, object_repr):

docs/releases/5.1.7.txt

@@ -22,3 +22,7 @@ Bugfixes
   of ``ManyToManyField`` related managers would always return ``0`` and
   ``False`` when the intermediary model back references used ``to_field``
   (:ticket:`36197`).
+
+* Fixed a regression in Django 5.1 where the ``pre_save`` and ``post_save``
+  signals for ``LogEntry`` were not sent when deleting a single object in the
+  admin (:ticket:`36217`).

docs/releases/5.1.txt

@@ -401,6 +401,11 @@ Miscellaneous
 * The minimum supported version of ``asgiref`` is increased from 3.7.0 to
   3.8.1.
 
+* To improve performance, the ``delete_selected`` admin action now uses
+  ``QuerySet.bulk_create()`` when creating multiple ``LogEntry`` objects. As a
+  result, ``pre_save`` and ``post_save`` signals for ``LogEntry`` are not sent
+  when multiple objects are deleted via this admin action.
+
 .. _deprecated-features-5.1:
 
 Features deprecated in 5.1

tests/admin_changelist/tests.py

@@ -1845,7 +1845,7 @@ class GetAdminLogTests(TestCase):
         """{% get_admin_log %} works without specifying a user."""
         user = User(username="jondoe", password="secret", email="super@example.com")
         user.save()
-        LogEntry.objects.log_actions(user.pk, [user], 1, single_object=True)
+        LogEntry.objects.log_actions(user.pk, [user], 1)
         context = Context({"log_entries": LogEntry.objects.all()})
         t = Template(
             "{% load log %}"

tests/admin_utils/test_logentry.py

@@ -5,6 +5,7 @@ from django.contrib.admin.models import ADDITION, CHANGE, DELETION, LogEntry
 from django.contrib.admin.utils import quote
 from django.contrib.auth.models import User
 from django.contrib.contenttypes.models import ContentType
+from django.db.models.signals import post_save, pre_save
 from django.test import TestCase, override_settings
 from django.urls import reverse
 from django.utils import translation
@@ -42,11 +43,23 @@ class LogEntryTests(TestCase):
             [cls.a1],
             CHANGE,
             change_message="Changed something",
-            single_object=True,
         )
 
     def setUp(self):
         self.client.force_login(self.user)
+        self.signals = []
+
+        pre_save.connect(self.pre_save_listener, sender=LogEntry)
+        self.addCleanup(pre_save.disconnect, self.pre_save_listener, sender=LogEntry)
+
+        post_save.connect(self.post_save_listener, sender=LogEntry)
+        self.addCleanup(post_save.disconnect, self.post_save_listener, sender=LogEntry)
+
+    def pre_save_listener(self, instance, **kwargs):
+        self.signals.append(("pre_save", instance))
+
+    def post_save_listener(self, instance, created, **kwargs):
+        self.signals.append(("post_save", instance, created))
 
     def test_logentry_save(self):
         """
@@ -288,6 +301,7 @@ class LogEntryTests(TestCase):
             for obj in queryset
         ]
         self.assertSequenceEqual(logs, expected_log_values)
+        self.assertEqual(self.signals, [])
 
     # RemovedInDjango60Warning.
     def test_log_action_fallback(self):
@@ -371,6 +385,8 @@ class LogEntryTests(TestCase):
             "created_1": "00:00",
         }
         changelist_url = reverse("admin:admin_utils_articleproxy_changelist")
+        expected_signals = []
+        self.assertEqual(self.signals, expected_signals)
 
         # add
         proxy_add_url = reverse("admin:admin_utils_articleproxy_add")
@@ -379,6 +395,10 @@ class LogEntryTests(TestCase):
         proxy_addition_log = LogEntry.objects.latest("id")
         self.assertEqual(proxy_addition_log.action_flag, ADDITION)
         self.assertEqual(proxy_addition_log.content_type, proxy_content_type)
+        expected_signals.extend(
+            [("pre_save", proxy_addition_log), ("post_save", proxy_addition_log, True)]
+        )
+        self.assertEqual(self.signals, expected_signals)
 
         # change
         article_id = proxy_addition_log.object_id
@@ -391,6 +411,10 @@ class LogEntryTests(TestCase):
         proxy_change_log = LogEntry.objects.latest("id")
         self.assertEqual(proxy_change_log.action_flag, CHANGE)
         self.assertEqual(proxy_change_log.content_type, proxy_content_type)
+        expected_signals.extend(
+            [("pre_save", proxy_change_log), ("post_save", proxy_change_log, True)]
+        )
+        self.assertEqual(self.signals, expected_signals)
 
         # delete
         proxy_delete_url = reverse(
@@ -401,6 +425,10 @@ class LogEntryTests(TestCase):
         proxy_delete_log = LogEntry.objects.latest("id")
         self.assertEqual(proxy_delete_log.action_flag, DELETION)
         self.assertEqual(proxy_delete_log.content_type, proxy_content_type)
+        expected_signals.extend(
+            [("pre_save", proxy_delete_log), ("post_save", proxy_delete_log, True)]
+        )
+        self.assertEqual(self.signals, expected_signals)
 
     def test_action_flag_choices(self):
         tests = ((1, "Addition"), (2, "Change"), (3, "Deletion"))
@@ -415,7 +443,6 @@ class LogEntryTests(TestCase):
             [self.a1],
             CHANGE,
             change_message="Article changed message",
-            single_object=True,
         )
         c1 = Car.objects.create()
         LogEntry.objects.log_actions(
@@ -423,7 +450,6 @@ class LogEntryTests(TestCase):
             [c1],
             ADDITION,
             change_message="Car created message",
-            single_object=True,
         )
         exp_str_article = escape(str(self.a1))
         exp_str_car = escape(str(c1))

tests/admin_views/test_history_view.py

@@ -66,7 +66,6 @@ class SeleniumTests(AdminSeleniumTestCase):
                 [self.superuser],
                 CHANGE,
                 change_message=f"Changed something {i}",
-                single_object=True,
             )
         self.admin_login(
             username="super",

tests/admin_views/tests.py

@@ -3881,21 +3881,18 @@ class AdminViewStringPrimaryKeyTest(TestCase):
             [cls.m1],
             2,
             change_message="Changed something",
-            single_object=True,
         )
         LogEntry.objects.log_actions(
             user_pk,
             [cls.m1],
             1,
             change_message="Added something",
-            single_object=True,
         )
         LogEntry.objects.log_actions(
             user_pk,
             [cls.m1],
             3,
             change_message="Deleted something",
-            single_object=True,
         )
 
     def setUp(self):