Restoring an object with "computed" attributes fails (#306)

There are attributes we call "computed" which don't have stored values
in the database. Their values are based on other attributes of the same
object or related objects.

Setting values for these attributes when creating an object fails with
an exception and makes no sense so we exclude them here.

One might argue to not store them for deleted objects in the first place
but the values might still be of interest e.g. VMs that ran on a
hypervisor.

serveradmin/serverdb/views.py

@@ -21,7 +21,8 @@
     ChangeCommit,
     Server,
     ServertypeAttribute,
-    Change, )
+    Change,
+)
 from serveradmin.serverdb.query_committer import CommitError, commit_query
 
 
@@ -154,12 +155,18 @@ def restore(request, change_id):
     change = get_object_or_404(Change, pk=change_id)
     server_object = change.change_json
 
-    # Remove related_via_attribute values they are implicit
-    related_attribute_ids = ServertypeAttribute.objects.filter(
-        servertype_id=server_object['servertype']).exclude(
-        related_via_attribute=None)
-    for attribute in related_attribute_ids:
-        server_object.pop(attribute.attribute_id)
+    # Remove related_via_attribute and "computed" attributes they are implicit
+    # and have no values in the database.
+    servertype_id = server_object['servertype']
+    exclude = ServertypeAttribute.objects.filter(servertype_id=servertype_id)
+    exclude = exclude.filter(
+        ~Q(related_via_attribute=None) |
+        Q(attribute__type__in=['supernet', 'domain', 'reverse'])
+    ).values_list('attribute_id', flat=True)
+
+    for attribute_id in exclude:
+        if attribute_id in server_object:
+            server_object.pop(attribute_id)
 
     try:
         commit = commit_query([server_object], user=request.user)