enable for_each support for output

[chz8494]

Current Terraform Version

Terraform version 0.12.10

Use-cases

I've tried newest Terraform and for_each provides an awesome feature that I need, so I'm looking for more from it now.
Let's say I have used for_each during resource definition and created my openstack networks, but I'd like to have output list all new networks IDs.

Attempted Solutions

Tried with for_each or count, none of them seems be allowed to be used in output.

[dan-petty]

I work around this by using for ... in on the same object that created the resources:

output "output_a" {
  value = {
    for key, value in var.object_a :
    key => {
      val_1      = resource_type.resource_a[key].val_1
    }
  }
  description = "Resource A val_1"
}
output "output_b" {
  value = {
    for key, value in var.object_b :
    key => resource_type.resource_b[key]
  }
  description = "Entire Resource B"
}

[iancward]

I've tried the list comprehension as documented, but that doesn't seem to work, either.

for example, if I have

resource "aws_network_acl_rule" "awedome_rule" {
  for_each [acl1, acl2, acl3]

  network_acl_id = each.value
  ...
}

output "awesome_rule_ids" {
  value = [for acl_rule in aws_network_acl_rule.awesome_rule : acl_rule.id]
}

Output is empty list.
With as much emphasis is put on remote state, it seems like this is a pretty sizable gap with the new for_each feature set.

[iancward]

The issue I ran into may be particular to the aws_network_acl_rule resource, so I opened hashicorp/terraform-provider-aws#11955