Set subnet_mapping element attributes to ForceNew

[mmdriley]

The way diffSet in Terraform works on Resource, the ForceNew property
on the Set has no effect unless ForceNew is also set on the resource's
attributes.

Without ForceNew on these attributes, changing subnet_mappings just
silently does nothing.

[mmdriley]

Example output without this change:

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  ~ aws_lb.test
      enable_http2:                            "" => "true"
      idle_timeout:                            "" => "60"
      subnet_mapping.2493713080.allocation_id: "" => ""
      subnet_mapping.2493713080.subnet_id:     "" => "subnet-d3d764ab"
      subnet_mapping.3213777275.allocation_id: "" => ""
      subnet_mapping.3213777275.subnet_id:     "subnet-d3d764aa" => ""


Plan: 0 to add, 1 to change, 0 to destroy.

[bflad]

Can you please add an acceptance test to cover the behavior?

[bflad]

Going to pull this in as-is -- thanks @mmdriley! 🚀

[bflad]

This has been released in version 1.15.0 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!