Check before accessing a nullable property

feudal/backend/models/__init__.py

@@ -199,7 +199,10 @@ class NewDeployment(models.Model):
 
     @property
     def services(self):
-        return self.vo.services.all()
+        if self.vo is not None:
+            return self.vo.services.all()
+        else:
+            return Service.objects.none()
 
     @property
     def sites(self):
@@ -303,10 +306,11 @@ class NewDeployment(models.Model):
         data = NewDeploymentSerializer(self).data
         msg = dumps(data)
 
-        RabbitMQInstance.load().publish_by_vo(
-            self.vo,
-            msg,
-        )
+        if self.vo is not None:
+            RabbitMQInstance.load().publish_by_vo(
+                self.vo,
+                msg,
+            )
 
     # sends a state update via RabbitMQ / STOMP to the users webpage instance
     def publish_to_user(self):
@@ -336,11 +340,17 @@ class NewDeployment(models.Model):
         self.save()
 
     def __str__(self):
-        return 'VO-Dep: ({}:{})#{}'.format(
-            self.vo,
-            self.user,
-            self.id,
-        )
+        if self.vo is not None:
+            return 'VO-Dep: ({}:{})#{}'.format(
+                self.vo,
+                self.user,
+                self.id,
+            )
+        else:
+            return 'VO-Dep: (!NO-VO!:{})#{}'.format(
+                self.user,
+                self.id,
+            )
 
 
 class NewDeploymentStateItem(models.Model):