The following CR is accepted by the dataplane-operator and quickly set to Ready. I think an empty deployment does not make sense as it does nothing, so it has to be a mistake from the user. Therefore I suggest to reject the CR from the validaton webhook if nodeSets is empty.

apiVersion: dataplane.openstack.org/v1beta1
kind: OpenStackDataPlaneDeployment
metadata:
  name: edpm-deployment-ipam
  namespace: openstack
spec:
  deploymentRequeueTime: 15
  nodeSets: []
  servicesOverride:[]