[5.1.x] Fixed #36234 -- Restored single_object argument to LogEntry.objects.log_actions().

Thank you Adam Johnson for the report and fix. Thank you Sarah Boyce for
your spot on analysis.

Regression in c09bceef68e5abb79accedd12dade16aa6577a09, which is
partially reverted in this branch.

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

Backport of 27b68bcadf1ab2e9f7fd223aed42db352ccdc62d from main.

4 files changed, 59 insertions, 4 deletions

diff --git a/django/contrib/admin/models.py b/django/contrib/admin/models.py
index 345b8cf341..957c9e4877 100644
--- a/django/contrib/admin/models.py
+++ b/django/contrib/admin/models.py
@@ -51,7 +51,9 @@ class LogEntryManager(models.Manager):
             change_message=change_message,
         )
 
-    def log_actions(self, user_id, queryset, action_flag, change_message=""):
+    def log_actions(
+        self, user_id, queryset, action_flag, change_message="", *, single_object=False
+    ):
         # RemovedInDjango60Warning.
         if type(self).log_action != LogEntryManager.log_action:
             warnings.warn(
@@ -94,7 +96,9 @@ class LogEntryManager(models.Manager):
         if len(log_entry_list) == 1:
             instance = log_entry_list[0]
             instance.save()
-            return instance
+            if single_object:
+                return instance
+            return [instance]
 
         return self.model.objects.bulk_create(log_entry_list)
 
diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index 4df5018804..5401bcabbe 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -954,6 +954,7 @@ class ModelAdmin(BaseModelAdmin):
             queryset=[obj],
             action_flag=ADDITION,
             change_message=message,
+            single_object=True,
         )
 
     def log_change(self, request, obj, message):
@@ -969,6 +970,7 @@ class ModelAdmin(BaseModelAdmin):
             queryset=[obj],
             action_flag=CHANGE,
             change_message=message,
+            single_object=True,
         )
 
     def log_deletion(self, request, obj, object_repr):
diff --git a/docs/releases/5.1.8.txt b/docs/releases/5.1.8.txt
index fd96acd0cb..e5143904a2 100644
--- a/docs/releases/5.1.8.txt
+++ b/docs/releases/5.1.8.txt
@@ -9,4 +9,6 @@ Django 5.1.8 fixes several bugs in 5.1.7.
 Bugfixes
 ========
 
-* ...
+* Fixed a regression in Django 5.1.7 where the removal of the ``single_object``
+  parameter unintentionally altered the signature and return type of
+  ``LogEntryManager.log_actions()`` (:ticket:`36234`).
diff --git a/tests/admin_utils/test_logentry.py b/tests/admin_utils/test_logentry.py
index 37ddb0da7d..43b6cf5573 100644
--- a/tests/admin_utils/test_logentry.py
+++ b/tests/admin_utils/test_logentry.py
@@ -271,12 +271,13 @@ class LogEntryTests(TestCase):
         content_type = ContentType.objects.get_for_model(self.a1)
         self.assertEqual(len(queryset), 3)
         with self.assertNumQueries(1):
-            LogEntry.objects.log_actions(
+            result = LogEntry.objects.log_actions(
                 self.user.pk,
                 queryset,
                 DELETION,
                 change_message=msg,
             )
+        self.assertEqual(len(result), len(queryset))
         logs = (
             LogEntry.objects.filter(action_flag=DELETION)
             .order_by("id")
@@ -300,6 +301,18 @@ class LogEntryTests(TestCase):
             )
             for obj in queryset
         ]
+        result_logs = [
+            (
+                entry.user_id,
+                entry.content_type_id,
+                str(entry.object_id),
+                entry.object_repr,
+                entry.action_flag,
+                entry.change_message,
+            )
+            for entry in result
+        ]
+        self.assertSequenceEqual(logs, result_logs)
         self.assertSequenceEqual(logs, expected_log_values)
         self.assertEqual(self.signals, [])
 
@@ -343,6 +356,40 @@ class LogEntryTests(TestCase):
         ]
         self.assertSequenceEqual(log_values, expected_log_values)
 
+    def test_log_actions_single_object_param(self):
+        queryset = Article.objects.filter(pk=self.a1.pk)
+        msg = "Deleted Something"
+        content_type = ContentType.objects.get_for_model(self.a1)
+        self.assertEqual(len(queryset), 1)
+        for single_object in (True, False):
+            self.signals = []
+            with self.subTest(single_object=single_object), self.assertNumQueries(1):
+                result = LogEntry.objects.log_actions(
+                    self.user.pk,
+                    queryset,
+                    DELETION,
+                    change_message=msg,
+                    single_object=single_object,
+                )
+                if single_object:
+                    self.assertIsInstance(result, LogEntry)
+                    entry = result
+                else:
+                    self.assertIsInstance(result, list)
+                    self.assertEqual(len(result), 1)
+                    entry = result[0]
+                self.assertEqual(entry.user_id, self.user.pk)
+                self.assertEqual(entry.content_type_id, content_type.id)
+                self.assertEqual(str(entry.object_id), str(self.a1.pk))
+                self.assertEqual(entry.object_repr, str(self.a1))
+                self.assertEqual(entry.action_flag, DELETION)
+                self.assertEqual(entry.change_message, msg)
+                expected_signals = [
+                    ("pre_save", entry),
+                    ("post_save", entry, True),
+                ]
+                self.assertEqual(self.signals, expected_signals)
+
     def test_recentactions_without_content_type(self):
         """
         If a LogEntry is missing content_type it will not display it in span