From 1fba4b7e32f18e643f6483068062c71a2019c807 Mon Sep 17 00:00:00 2001
From: jeremystretch <jeremy@netverity.dev>
Date: Tue, 13 Apr 2021 13:23:25 -0400
Subject: [PATCH] Fixes #5419: Update parent device/VM when deleting a primary
 IP

---
 docs/release-notes/version-2.10.md |  1 +
 netbox/ipam/apps.py                |  3 +++
 netbox/ipam/signals.py             | 21 +++++++++++++++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 netbox/ipam/signals.py

diff --git a/docs/release-notes/version-2.10.md b/docs/release-notes/version-2.10.md
index 974eb00b0..2675bac5f 100644
--- a/docs/release-notes/version-2.10.md
+++ b/docs/release-notes/version-2.10.md
@@ -4,6 +4,7 @@
 
 ### Bug Fixes
 
+* [#5419](https://github.com/netbox-community/netbox/issues/5419) - Update parent device/VM when deleting a primary IP
 * [#6144](https://github.com/netbox-community/netbox/issues/6144) - Fix MAC address field display in VM interfaces search form
 * [#6152](https://github.com/netbox-community/netbox/issues/6152) - Fix custom field filtering for cables, virtual chassis
 
diff --git a/netbox/ipam/apps.py b/netbox/ipam/apps.py
index fd4af74b0..413c8c1bc 100644
--- a/netbox/ipam/apps.py
+++ b/netbox/ipam/apps.py
@@ -4,3 +4,6 @@ from django.apps import AppConfig
 class IPAMConfig(AppConfig):
     name = "ipam"
     verbose_name = "IPAM"
+
+    def ready(self):
+        import ipam.signals
diff --git a/netbox/ipam/signals.py b/netbox/ipam/signals.py
new file mode 100644
index 000000000..a8fce8310
--- /dev/null
+++ b/netbox/ipam/signals.py
@@ -0,0 +1,21 @@
+from django.db.models.signals import pre_delete
+from django.dispatch import receiver
+
+from dcim.models import Device
+from virtualization.models import VirtualMachine
+from .models import IPAddress
+
+
+@receiver(pre_delete, sender=IPAddress)
+def clear_primary_ip(instance, **kwargs):
+    """
+    When an IPAddress is deleted, trigger save() on any Devices/VirtualMachines for which it
+    was a primary IP.
+    """
+    field_name = f'primary_ip{instance.family}'
+    device = Device.objects.filter(**{field_name: instance}).first()
+    if device:
+        device.save()
+    virtualmachine = VirtualMachine.objects.filter(**{field_name: instance}).first()
+    if virtualmachine:
+        virtualmachine.save()