Closes #19627: Object change migrators (#19628)

* Initial work on ObjectChange data migrations

* Fix migration bug

* Add migrators for MAC address assignments

* Update reverting kwarg; allow pop() to fail

* Cross-reference MAC address migrators

* Split migrator logic across migrations

* Add missing migrator

netbox/dcim/migrations/0188_racktype.py

@@ -100,3 +100,16 @@ class Migration(migrations.Migration):
             ),
         ),
     ]
+
+
+def oc_rename_type(objectchange, reverting):
+    for data in (objectchange.prechange_data, objectchange.postchange_data):
+        if data is None:
+            continue
+        if 'type' in data:
+            data['form_factor'] = data.pop('type')
+
+
+objectchange_migrators = {
+    'dcim.rack': oc_rename_type,
+}

netbox/dcim/migrations/0200_populate_mac_addresses.py

@@ -1,4 +1,6 @@
 import django.db.models.deletion
+from django.apps import apps
+from django.contrib.contenttypes.models import ContentType
 from django.db import migrations, models
 
 
@@ -15,7 +17,7 @@ def populate_mac_addresses(apps, schema_editor):
             assigned_object_type=interface_ct,
             assigned_object_id=interface.pk
         )
-        for interface in Interface.objects.filter(mac_address__isnull=False)
+        for interface in Interface.objects.using(db_alias).filter(mac_address__isnull=False)
     ]
     MACAddress.objects.using(db_alias).bulk_create(mac_addresses, batch_size=100)
 
@@ -51,3 +53,43 @@ class Migration(migrations.Migration):
             name='mac_address',
         ),
     ]
+
+
+# See peer migrator in virtualization.0048_populate_mac_addresses before making changes
+def oc_interface_primary_mac_address(objectchange, reverting):
+    MACAddress = apps.get_model('dcim', 'MACAddress')
+    interface_ct = ContentType.objects.get_by_natural_key('dcim', 'interface')
+
+    # Swap data order if the change is being reverted
+    if not reverting:
+        before, after = objectchange.prechange_data, objectchange.postchange_data
+    else:
+        before, after = objectchange.postchange_data, objectchange.prechange_data
+
+    if after.get('mac_address') != before.get('mac_address'):
+        # Create & assign the new MACAddress (if any)
+        if after.get('mac_address'):
+            mac = MACAddress.objects.create(
+                mac_address=after['mac_address'],
+                assigned_object_type=interface_ct,
+                assigned_object_id=objectchange.changed_object_id,
+            )
+            after['primary_mac_address'] = mac.pk
+        else:
+            after['primary_mac_address'] = None
+        # Delete the old MACAddress (if any)
+        if before.get('mac_address'):
+            MACAddress.objects.filter(
+                mac_address=before['mac_address'],
+                assigned_object_type=interface_ct,
+                assigned_object_id=objectchange.changed_object_id,
+            ).delete()
+        before['primary_mac_address'] = None
+
+    before.pop('mac_address', None)
+    after.pop('mac_address', None)
+
+
+objectchange_migrators = {
+    'dcim.interface': oc_interface_primary_mac_address,
+}