Mock provider errors on plan while testing write only attribute

[wyardley]

Terraform Version

Terraform v1.11.3
on darwin_arm64
+ provider registry.terraform.io/hashicorp/google v6.28.0

Terraform Configuration Files

in main.tf

resource "google_secret_manager_secret" "this" {
  secret_id = var.secret_id
  replication {
    auto {}
  }
}
resource "google_secret_manager_secret_version" "this" {
  count          = var.secret_data_wo == null ? 0 : 1
  secret         = google_secret_manager_secret.this.id
  secret_data_wo = var.secret_data_wo
}

in main.tftest.hcl:

mock_provider "google" {
  mock_resource "google_secret_manager_secret" {
    defaults = {
      project = "test-foo"
    }
  }
  mock_resource "google_secret_manager_secret_version" {
    defaults = {
      project = "test-foo"
    }
  }
}

run "simple_example" {
  variables {
    secret_id      = "foobar"
    secret_data_wo = sensitive("hunter2")
  }
}

Debug Output

(let me know if you need this)

Expected Behavior

The test should pass

Actual Behavior

% tf test            
main.tftest.hcl... in progress
  run "simple_example"... fail
╷
│ Error: Provider produced invalid plan
│ 
│ Provider "provider[\"registry.terraform.io/hashicorp/google\"]" returned a value for
│ the write-only attribute "google_secret_manager_secret_version.this[0].secret_data_wo"
│ during planning. Write-only attributes cannot be read back from the provider. This is
│ a bug in the provider, which should be reported in the provider's own issue tracker.
╵
main.tftest.hcl... tearing down
main.tftest.hcl... fail

Steps to Reproduce

1. terraform init
2. terraform test

Additional Context

I know the warning says to file a provider bug for this error, but I verified and pretty sure this is an issue with the mock provider. A plan-only test with the real provider works fine.

References

No response

Generative AI / LLM assisted development?

No response

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