Creating a network with no secondary ranges fails

[morgante]

The output expects at least one subnet to have a secondary range.

Config:

module "network2" {
  source       = "../../modules/network"
  project_id   = "${data.terraform_remote_state.projects.net-host-project-id}"
  network_name = "sandbox-vpc2"
  shared_vpc_host = "true"

  subnets = [
    {
      subnet_name           = "sandbox-compute"
      subnet_ip             = "10.18.0.0/20"
      subnet_region         = "us-central1"
      subnet_private_access = false
    },
  ]

  secondary_ranges = {
    sandbox-compute = []
  }
}

Error:

Error: Error running plan: 1 error(s) occurred:

* module.network2.output.subnets_secondary_ranges: Resource 'google_compute_subnetwork.subnetwork' does not have attribute 'secondary_ip_range' for variable 'google_compute_subnetwork.subnetwork.*.secondary_ip_range'

[rubencode]

I believe this could be failing due to the output.tf in the root module folder:
output "subnets_secondary_ranges" {
value = "${google_compute_subnetwork.subnetwork.*.secondary_ip_range}"
description = "The secondary ranges associated with these subnets"
}

[angstwad]

It's definitely failing due to lines here... https://github.com/terraform-google-modules/terraform-google-network/blob/master/outputs.tf#L52-L54