14147 Prevent logging to Change Log when no changes are made (#14477)

* 14147 Prevent logging to Change Log when no changes are made

* 14147 add test

* 14147 add exclude_fields to serialize_object

* 14147 make skip empty default to True

* 14147 remove override of to_objectchange

* Misc cleanup

---------

Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>

netbox/extras/models/change_logging.py

@@ -135,3 +135,7 @@ class ObjectChange(models.Model):
 
     def get_action_color(self):
         return ObjectChangeActionChoices.colors.get(self.action)
+
+    @property
+    def has_changes(self):
+        return self.prechange_data != self.postchange_data

netbox/extras/signals.py

@@ -80,9 +80,10 @@ def handle_changed_object(sender, instance, **kwargs):
             )
         else:
             objectchange = instance.to_objectchange(action)
-            objectchange.user = request.user
-            objectchange.request_id = request.id
-            objectchange.save()
+            if objectchange and objectchange.has_changes:
+                objectchange.user = request.user
+                objectchange.request_id = request.id
+                objectchange.save()
 
     # If this is an M2M change, update the previously queued webhook (from post_save)
     queue = events_queue.get()

netbox/extras/tests/test_changelog.py

@@ -1,4 +1,5 @@
 from django.contrib.contenttypes.models import ContentType
+from django.test import override_settings
 from django.urls import reverse
 from rest_framework import status
 
@@ -207,6 +208,66 @@ class ChangeLogViewTest(ModelViewTestCase):
         self.assertEqual(objectchange.prechange_data['slug'], sites[0].slug)
         self.assertEqual(objectchange.postchange_data, None)
 
+    @override_settings(CHANGELOG_SKIP_EMPTY_CHANGES=False)
+    def test_update_object_change(self):
+        # Create a Site
+        site = Site.objects.create(
+            name='Site 1',
+            slug='site-1',
+            status=SiteStatusChoices.STATUS_PLANNED,
+            custom_field_data={
+                'cf1': None,
+                'cf2': None
+            }
+        )
+
+        # Update it with the same field values
+        form_data = {
+            'name': site.name,
+            'slug': site.slug,
+            'status': SiteStatusChoices.STATUS_PLANNED,
+        }
+        request = {
+            'path': self._get_url('edit', instance=site),
+            'data': post_data(form_data),
+        }
+        self.add_permissions('dcim.change_site', 'extras.view_tag')
+        response = self.client.post(**request)
+        self.assertHttpStatus(response, 302)
+
+        # Check that an ObjectChange record has been created
+        self.assertEqual(ObjectChange.objects.count(), 1)
+
+    @override_settings(CHANGELOG_SKIP_EMPTY_CHANGES=True)
+    def test_update_object_nochange(self):
+        # Create a Site
+        site = Site.objects.create(
+            name='Site 1',
+            slug='site-1',
+            status=SiteStatusChoices.STATUS_PLANNED,
+            custom_field_data={
+                'cf1': None,
+                'cf2': None
+            }
+        )
+
+        # Update it with the same field values
+        form_data = {
+            'name': site.name,
+            'slug': site.slug,
+            'status': SiteStatusChoices.STATUS_PLANNED,
+        }
+        request = {
+            'path': self._get_url('edit', instance=site),
+            'data': post_data(form_data),
+        }
+        self.add_permissions('dcim.change_site', 'extras.view_tag')
+        response = self.client.post(**request)
+        self.assertHttpStatus(response, 302)
+
+        # Check that no ObjectChange records have been created
+        self.assertEqual(ObjectChange.objects.count(), 0)
+
 
 class ChangeLogAPITest(APITestCase):