Also missing support for TF 1.3.0 optional() with second argument, the attribute default value.

[sarath-s-kumar]

          Also missing support for TF 1.3.0 optional() with second argument, the attribute default value.

variables.tf:5,27-74: Invalid type specification; Optional attribute modifier expects only one argument: the attribute type.```

_Originally posted by @ambis in https://github.com/tenable/terrascan/issues/1331#issuecomment-1257892023_
            

[mloskot]

First, linking https://github.com/tenable/terrascan/issues/1331#issuecomment-1257892023 to fix the cross referencing broken due to terrible formatting above.

Next, copying my https://github.com/tenable/terrascan/issues/1468#issuecomment-1423234053 below

The module_variable_optional_attrs is gone from Terraform 1.3 as per

• https://github.com/hashicorp/terraform/issues/31692
• https://developer.hashicorp.com/terraform/language/v1.3.x/upgrade-guides#concluding-the-optional-attributes-experiment

and the latest Terrascan v1.18 is complaining as it seems not support the built-in optional

(...)/terraform_azurerm_db_sql/variables.tf:234,1-42: Optional object type attributes are experimental;
  This feature is currently an opt-in experiment, subject to change in future releases based on feedback.

where the variables.tf contains

variable "single_databases_configuration" {
  description = "List of databases configurations"
  type = list(object({
    name                        = string
    sku_name                    = optional(string)
    license_type                = optional(string)
    collation                   = optional(string)
    max_size_gb                 = optional(number)
    zone_redundant              = optional(bool)
    min_capacity                = optional(number)
    auto_pause_delay_in_minutes = optional(number)
    threat_detection_policy = optional(object({
      state = bool
    }))
    retention_days      = optional(number)
    weekly_retention    = optional(string)
    monthly_retention   = optional(string)
    yearly_retention    = optional(string)
    week_of_year        = optional(number)
    database_extra_tags = optional(map(any))
  }))
  default = []
}

[adhodgson1]

I just wanted to add a quick comment as I didn't think the comments in this thread outlined the issue clearly. Using Terrascan v1.18.1 In my setup the optional value in the strongly typed map works:

variable "single_databases_configuration" {
  description = "List of databases configurations"
  type = list(object({
    name                        = string
    sku_name                    = optional(string)
[...]
  }))
}

However what I am seeing and I believe is the intent of this issue is that when we add the attribute default value to the variable definition Terrascan throws an error:

variable "single_databases_configuration" {
  description = "List of databases configurations"
  type = list(object({
    name                        = string
    sku_name                    = optional(string, "Standard")
[...]
  }))
}

This is valid syntax from Terraform 1.3, however Terrascan complains:

Scan Errors -

    -----------------------------------------------------------------------

    IaC Type            :   terraform
    Directory           :   [...]
    Error Message       :   diagnostic errors while loading terraform config dir '[...]'. error from terraform:

[...]\variables.tf:44,32-45: Invalid type specification; Optional attribute modifier expects only one argument: the attribute type.

I use Terrascan as part of Github Super-Linter and due to the error parsing the Terraform code using this feature I am having to disable it completely from the run (i.e, I don't think I can fix this with an ignore rule).

[mloskot]

FYA, as follow-up to this issue, I've asked about Terrascan status here

• https://github.com/tenable/terrascan/discussions/1569

[manish-shanker-osttra]

Is there any update on this?