(terraform/powervc-openshift) openstack_compute_servergroup_v2.vm1-servergroup-affinity is empty tuple

[GRuuuuu]

Hello,

I tested devops-automation/terraform/powervc-openshift project.

My Terraform version is :

$ terraform -v
Terraform v0.12.24
+ provider.null v2.1.2
+ provider.openstack v1.26.0

And the problem occurred when the number of MasterVM is 1.
If I declared number of master vm is 1 in tfvars file, then the upcoming error is like this :

$ terraform plan

...
Error: Invalid index

  on vm1-Master.tf line 202, in resource "openstack_compute_instance_v2" "vm1":
 202:     group = "${openstack_compute_servergroup_v2.vm1-servergroup-affinity[0].id}"
    |----------------
    | openstack_compute_servergroup_v2.vm1-servergroup-affinity is empty tuple

The given key does not identify an element in this collection value.

Reason of this error is from vm1-Master.tf line 143.
if I declare vm1_number is 1 then the count of vm1-servergroup-affinity goes 0.

resource "openstack_compute_servergroup_v2" "vm1-servergroup-affinity" {
  count    = "${var.vm1_number > 1? 1 : 0}"
  name     = "${var.vm1_name}-servergroup"
  policies = ["soft-anti-affinity"]
}

So, In vm1-Master.tf line 202 refer to empty array. It causes an error.

But, I saw another line (ex line 152) wrote down like this : count = "${var.vm1_number > 0 ? 1 : 0}"

So my question is :

1. line 202(vm1-Master.tf) is intended design?
2. If so, Why is that error occurred?

+) In Terraform v0.12.24, Interpolation-only expressions and Quoted references are deprecated in further version. so I think terraform code in this project should be changed.

Thank you

[yussufsh]

@GRuuuuu Thanks for reporting the issue. The issue is related to better static checking in latest Terraform version.

I will raise a PR for the fix soon.