cdktf: HCL Lifecycle Objects not Found in Typescript

[HackedRico]

Expected Behavior

When running CDKTF init from a Terraform Project Template in HCL, the generated CDKTF Typescript does not recognize Terraform Lifecycle ignore_changes field.

Actual Behavior

Generated CDKTF App properly handles Terraform Lifecycle fields.

Steps to Reproduce

1. Create a Terraform Project with resources that uses Lifecycle feature. Sample Test Case:

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "6.14.1"
    }
  }
}

provider "aws" {
}

resource "aws_instance" "example" {
  ami           = "resolve:ssm:/aws/service/ami-amazon-linux-latest/al2023-ami-kernel-default-x86_64"
  instance_type = "t3.micro"

  tags = {
    Name = "HelloWorld"
  }

  lifecycle {
    ignore_changes = [ tags ]
  }
}

2. Initialize CDKTF from Terraform Project template

cdktf init --template=typescript \
    --from-terraform-project=../terraform \
    --local \
    --providers=aws

3. Observe generated main.ts file for invalid lifecycle.

Versions

cdktf debug
language: typescript
cdktf-cli: 0.21.0
node: v22.17.1
cdktf: 0.21.0
constructs: 10.4.2
jsii: null
terraform: 1.13.0
arch: x64
os: darwin 24.6.0
providers
aws@6.14.1 (LOCAL)
        terraform provider version: 6.14.1
@cdktf/provider-aws (PREBUILT)
        terraform provider version: 6.14.1 
        prebuilt provider version: 21.11.1
        cdktf version: ^0.21.0

Providers

┌───────────────┬──────────────────┬─────────┬────────────┬─────────────────────┬─────────────────┐
│ Provider Name │ Provider Version │ CDKTF   │ Constraint │ Package Name        │ Package Version │
├───────────────┼──────────────────┼─────────┼────────────┼─────────────────────┼─────────────────┤
│ aws           │ 6.14.1           │         │ 6.14.1     │                     │                 │
├───────────────┼──────────────────┼─────────┼────────────┼─────────────────────┼─────────────────┤
│ aws           │ 6.14.1           │ ^0.21.0 │            │ @cdktf/provider-aws │ 21.11.1         │
└───────────────┴──────────────────┴─────────┴────────────┴─────────────────────┴─────────────────┘```

Gist

No response

Possible Solutions

From Terraform code converted to Typescript, create Lifecycle fields as String Arrays. The values are recognized, needs conversion to be string values.

Workarounds

Based on the CDKTF Lifecycle Resource defined, it expects an string array.

export interface TerraformResourceLifecycle {
    readonly createBeforeDestroy?: boolean;
    readonly preventDestroy?: boolean;
    readonly ignoreChanges?: string[] | "all";
    readonly replaceTriggeredBy?: Array<ITerraformDependable | string>;
    readonly precondition?: Precondition[];
    readonly postcondition?: Postcondition[];
}

Whereas, the CDKTF init from Template does not create an String array. It creates the following:

      lifecycle: {
        ignoreChanges: [ tags ],
      },

I changed it to be an String and it worked, after change:

      lifecycle: {
        ignoreChanges: [ "tags" ],
      },

Anything Else?

No response

References

No response

Help Wanted

• I'm interested in contributing a fix myself

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