Fixes #23150: Pre-select the parent object on 'create & add another' for non-cloning models

ObjectEditView and ComponentCreateView build the add-another redirect
from prepare_cloned_fields(), which returns an empty QueryDict for models
that don't support cloning - the component templates (InterfaceTemplate,
etc.). When adding components to a device type via 'Create & Add
Another', the parent device type was dropped and the form came back
blank.

For non-cloning models, fall back to pre-selecting any parent object the
instance links to (device type/module type/device/module). Models that
support cloning (device components etc.) are unaffected and continue to
use clone() as before.

Fixes #23150

netbox/dcim/tests/test_views.py

@@ -2425,6 +2425,22 @@ class InterfaceTemplateTestCase(ViewTestCases.DeviceComponentTemplateViewTestCas
     model = InterfaceTemplate
     validation_excluded_fields = ('name', 'label')
 
+    def test_create_object_add_another_preserves_device_type(self):
+        # Regression test for #23150: "create & add another" must retain the
+        # parent device type, since component templates don't support cloning
+        self.add_permissions('dcim.add_interfacetemplate')
+
+        device_type = DeviceType.objects.first()
+        data = dict(self.form_data)
+        data.update({
+            '_addanother': True,
+            'name': 'Interface Template Y',
+        })
+        response = self.client.post(self._get_url('add'), data=post_data(data))
+        self.assertHttpStatus(response, 302)
+        self.assertIn(f'device_type={device_type.pk}', response.headers['Location'])
+
+
     @classmethod
     def setUpTestData(cls):
         manufacturer = Manufacturer.objects.create(name='Manufacturer 1', slug='manufacturer-1')
@@ -3901,6 +3917,20 @@ class InterfaceTestCase(ViewTestCases.DeviceComponentViewTestCase):
     model = Interface
     validation_excluded_fields = ('name', 'label')
 
+    def test_bulk_create_add_another_preserves_device(self):
+        # Regression test for #23150: "add components" with "create & add another"
+        # must retain the parent device, since components don't support cloning
+        self.add_permissions('dcim.add_interface')
+
+        device = Device.objects.first()
+        response = self.client.post(
+            self._get_url('add'),
+            data=post_data(dict(self.bulk_create_data, _addanother=True)),
+        )
+        self.assertHttpStatus(response, 302)
+        self.assertIn(f'device={device.pk}', response.headers['Location'])
+
+
     @classmethod
     def setUpTestData(cls):
         device = create_test_device('Device 1')

netbox/utilities/querydict.py

@@ -49,7 +49,13 @@ def prepare_cloned_fields(instance):
     """
     # Generate the clone attributes from the instance
     if not issubclass(type(instance), CloningMixin):
-        return QueryDict(mutable=True)
+        # The model doesn't support cloning (e.g. device components & templates), but we
+        # can still pre-select its parent object when the user clicks "create & add another"
+        params = []
+        for field_name in ('device_type', 'module_type', 'device', 'module'):
+            if value := getattr(instance, f'{field_name}_id', None):
+                params.append((field_name, value))
+        return QueryDict(urlencode(params), mutable=True)
     attrs = instance.clone()
 
     # Prepare QueryDict parameters