cdktf: synth --hcl fails to render object correctly

[elruwen]

Expected Behavior

I got a little cdktf example program:

import {Construct} from "constructs";
import {App, TerraformStack} from "cdktf";
import {KubernetesProvider} from "@cdktf/provider-kubernetes/lib/provider";
import {Manifest} from "@cdktf/provider-kubernetes/lib/manifest";

class MyStack extends TerraformStack {
    constructor(scope: Construct, id: string) {
        super(scope, id);

        new KubernetesProvider(this, "k8sprovider", {})

        new Manifest(this, "knative-service", {
            manifest: {
                apiVersion: "serving.knative.dev/v1",
                kind: "Service",
                metadata: {
                    name: "ruwen-app",
                    namespace: "ruwen-ns",
                    labels: {
                        "networking.knative.dev/visibility": "cluster-local",
                        "app": "ruwen-app"
                    }
                },
            }
        })
    }
}

const app = new App();
new MyStack(app, "cdktf");
app.synth();

When running synth with json, the generated terraform code looks correct. I would expect the --hcl version also is able to render metadata as a nested structure.

Actual Behavior

Json result:

{
  "//": {
    "metadata": {
      "backend": "local",
      "stackName": "cdktf",
      "version": "0.20.4"
    },
    "outputs": {
    }
  },
  "provider": {
    "kubernetes": [
      {
      }
    ]
  },
  "resource": {
    "kubernetes_manifest": {
      "knative-service": {
        "//": {
          "metadata": {
            "path": "cdktf/knative-service",
            "uniqueId": "knative-service"
          }
        },
        "manifest": {
          "apiVersion": "serving.knative.dev/v1",
          "kind": "Service",
          "metadata": {
            "labels": {
              "app": "ruwen-app",
              "networking.knative.dev/visibility": "cluster-local"
            },
            "name": "ruwen-app",
            "namespace": "ruwen-ns"
          }
        }
      }
    }
  },
  "terraform": {
    "backend": {
      "local": {
        "path": "/home/ruwen/src/local/cdktf/terraform.cdktf.tfstate"
      }
    },
    "required_providers": {
      "kubernetes": {
        "source": "kubernetes",
        "version": "2.25.2"
      }
    }
  }
}

HCL version - spot the [Object object] rendering

terraform {
  required_providers {
    kubernetes = {
      version = "2.25.2"
      source  = "kubernetes"
    }
  }
  backend "local" {
    path = "/home/ruwen/src/local/cdktf/terraform.cdktf.tfstate"
  }


}

provider "kubernetes" {
}
resource "kubernetes_manifest" "knative-service" {
  manifest = {
    apiVersion = "serving.knative.dev/v1"
    kind       = "Service"
    metadata   = [object Object]
  }
}

Steps to Reproduce

Example file:

import {Construct} from "constructs";
import {App, TerraformStack} from "cdktf";
import {KubernetesProvider} from "@cdktf/provider-kubernetes/lib/provider";
import {Manifest} from "@cdktf/provider-kubernetes/lib/manifest";

class MyStack extends TerraformStack {
    constructor(scope: Construct, id: string) {
        super(scope, id);

        new KubernetesProvider(this, "k8sprovider", {})

        new Manifest(this, "knative-service", {
            manifest: {
                apiVersion: "serving.knative.dev/v1",
                kind: "Service",
                metadata: {
                    name: "ruwen-app",
                    namespace: "ruwen-ns",
                    labels: {
                        "networking.knative.dev/visibility": "cluster-local",
                        "app": "ruwen-app"
                    }
                },
            }
        })
    }
}

const app = new App();
new MyStack(app, "cdktf");
app.synth();

Run cdktf synth --hcl

Versions

cdktf debug
language: typescript
cdktf-cli: 0.20.4
node: v18.15.0
cdktf: 0.20.4
constructs: 10.3.0
jsii: null
terraform: 1.7.2
arch: x64
os: linux 6.1.0-17-amd64
providers
@cdktf/provider-aws (PREBUILT)
terraform provider version: 5.33.0
prebuilt provider version: 19.2.0
cdktf version: ^0.20.0
@cdktf/provider-kubernetes (PREBUILT)
terraform provider version: 2.25.2
prebuilt provider version: 11.0.0
cdktf version: ^0.20.0
@cdktf/provider-local (PREBUILT)
terraform provider version: 2.4.1
prebuilt provider version: 10.0.0
cdktf version: ^0.20.0

Providers

┌───────────────┬──────────────────┬─────────┬────────────┬────────────────────────────┬─────────────────┐
│ Provider Name │ Provider Version │ CDKTF │ Constraint │ Package Name │ Package Version │
├───────────────┼──────────────────┼─────────┼────────────┼────────────────────────────┼─────────────────┤
│ aws │ 5.33.0 │ ^0.20.0 │ │ @cdktf/provider-aws │ 19.2.0 │
├───────────────┼──────────────────┼─────────┼────────────┼────────────────────────────┼─────────────────┤
│ kubernetes │ 2.25.2 │ ^0.20.0 │ │ @cdktf/provider-kubernetes │ 11.0.0 │
├───────────────┼──────────────────┼─────────┼────────────┼────────────────────────────┼─────────────────┤
│ local │ 2.4.1 │ ^0.20.0 │ │ @cdktf/provider-local │ 10.0.0 │
└───────────────┴──────────────────┴─────────┴────────────┴────────────────────────────┴─────────────────┘

Gist

No response

Possible Solutions

No response

Workarounds

Don't use hcl

Anything Else?

I think the manifest resource is a special one, since it allows inside manifest anything.

References

No response

Help Wanted

• I'm interested in contributing a fix myself

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