Fixes #4838: Fix rack power utilization display for racks without devices

docs/release-notes/version-2.8.md

@@ -6,6 +6,7 @@
 
 * [#4821](https://github.com/netbox-community/netbox/issues/4821) - Restrict group options by selected site when bulk editing VLANs
 * [#4835](https://github.com/netbox-community/netbox/issues/4835) - Support passing multiple initial values for multiple choice fields
+* [#4838](https://github.com/netbox-community/netbox/issues/4838) - Fix rack power utilization display for racks without devices
 
 ---
 

netbox/dcim/models/__init__.py

@@ -787,7 +787,7 @@ class Rack(ChangeLoggedModel, CustomFieldModel):
         )
 
         if power_stats:
-            allocated_draw_total = sum(x['allocated_draw_total'] for x in power_stats)
+            allocated_draw_total = sum(x['allocated_draw_total'] or 0 for x in power_stats)
             available_power_total = sum(x['available_power'] for x in power_stats)
             return int(allocated_draw_total / available_power_total * 100) or 0
         return 0