Fixes #13649: Permit zero-length cables

netbox/dcim/migrations/0182_zero_length_cable_fix.py

@@ -0,0 +1,22 @@
+from django.db import migrations
+
+
+def update_cable_lengths(apps, schema_editor):
+    Cable = apps.get_model('dcim', 'Cable')
+
+    # Set the absolute length for any zero-length Cables
+    Cable.objects.filter(length=0).update(_abs_length=0)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('dcim', '0181_rename_device_role_device_role'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=update_cable_lengths,
+            reverse_code=migrations.RunPython.noop
+        ),
+    ]