Fixed bug in which a device's device redundancy group priority was no…

…t being set to `None` when the device redundancy group was deleted. (nautobot#4737)

Co-authored-by: Hanlin Miao <[email protected]>

changes/4718.fixed

@@ -0,0 +1 @@
+Fixed bug in which a device's device redundancy group priority was not being set to `None` when the device redundancy group was deleted.

nautobot/dcim/signals.py

@@ -11,6 +11,7 @@
     Cable,
     CablePath,
     Device,
+    DeviceRedundancyGroup,
     PathEndpoint,
     PowerPanel,
     Rack,
@@ -146,6 +147,22 @@ def handle_rack_location_change(instance, created, raw=False, **kwargs):
                 device.save()
 
 
+#
+# Device redundancy group
+#
+
+
+@receiver(pre_delete, sender=DeviceRedundancyGroup)
+def clear_deviceredundancygroup_members(instance, **kwargs):
+    """
+    When a DeviceRedundancyGroup is deleted, nullify the device_redundancy_group_priority field of its prior members.
+    """
+    devices = Device.objects.filter(device_redundancy_group=instance.pk)
+    for device in devices:
+        device.device_redundancy_group_priority = None
+        device.save()
+
+
 #
 # Virtual chassis
 #

nautobot/dcim/tests/test_signals.py

@@ -4,6 +4,7 @@
 
 from nautobot.dcim.models import (
     Device,
+    DeviceRedundancyGroup,
     DeviceType,
     Location,
     LocationType,
@@ -69,3 +70,42 @@ def test_master_device_null_vc_assignment(self):
         self.device.refresh_from_db()
         self.assertEqual(self.device.vc_position, 1)
         self.assertEqual(self.device.virtual_chassis, virtualchassis)
+
+
+class DeviceRedundancyGroupTest(TestCase):
+    """Class to test signals for DeviceRedundancyGroup."""
+
+    @classmethod
+    def setUpTestData(cls):
+        """Setup Test Data for DeviceRedundancyGroup Signal tests."""
+        location = Location.objects.filter(location_type=LocationType.objects.get(name="Campus")).first()
+        manufacturer = Manufacturer.objects.first()
+        devicetype = DeviceType.objects.create(manufacturer=manufacturer, model="Device Type")
+        devicerole = Role.objects.get_for_model(Device).first()
+        devicestatus = Status.objects.get_for_model(Device).first()
+
+        cls.device = Device.objects.create(
+            name="Device 1",
+            device_type=devicetype,
+            role=devicerole,
+            status=devicestatus,
+            location=location,
+        )
+
+    def test_device_redundancy_group_priority_is_null(self):
+        """Test device with not null device_redundancy_group_priority is null after its device redundancy group is deleted.
+
+        This test is for https://github.com/nautobot/nautobot/issues/4718
+        """
+        deviceredundancygroup = DeviceRedundancyGroup.objects.first()
+
+        self.device.device_redundancy_group = deviceredundancygroup
+        self.device.device_redundancy_group_priority = 1
+        self.device.validated_save()
+
+        deviceredundancygroup.delete()
+
+        self.device.refresh_from_db()
+
+        self.assertIsNone(self.device.device_redundancy_group)
+        self.assertIsNone(self.device.device_redundancy_group_priority)