inconsistent behaviour for resources that can have repeated blocks defined with HCL2

[crivetechie]

Hello, we are having some issues writing policies for resource that may contain repeated blocks.

It looks like the behaviour of conftest is to produce an object when there's a single block and an array if the block is repeated.

See the example below definining two kubernetes_deployment resources, the first using a single container block and the second using 2 containers blocks

resource "kubernetes_deployment" "example-single-block" {
  spec {
    template {
      spec {
        container {
          name = "one"
        }
      }
    }
  }
}

resource "kubernetes_deployment" "example-multiple-blocks" {
  spec {
    template {
      spec {
        container {
          name = "one"
        }
        container {
          name = "two"
        }
      }
    }
  }
}

the above is parsed as

"resource": {
    "kubernetes_deployment": {
      "example-multiple-blocks": {
        "spec": {
          "template": {
            "spec": {
              "container": [
                {
                  "name": "one"
                },
                {
                  "name": "two"
                }
              ]
            }
          }
        }
      },
      "example-single-block": {
        "spec": {
          "template": {
            "spec": {
              "container": {
                "name": "one"
              }
            }
          }
        }
      }
    }

as you can see spec.template.spec.container in example-multiple-blocks is an array, it is an object in example-single-block

Accoriding to #266 I was expecting this to be resolved but it isn't, looks like conftest is using version 0.3.1 of hcl2json lib which doesn't include the fix.
I am wondering if there was a decision to lock to [email protected] to avoid introducing breaking changes and if there's any plan for upgrading to latest version. Thank you!

[jalseth]

@crivetechie We don't lock dependencies, but we typically only bump them if there is a reported issue. Can you confirm if updating this dependency solves your problem?

[crivetechie]

@jalseth updating the dependency solves the problem, however it introducing a list of changes that will break existing policies.

I've opened a PR in my fork to demonstrate the impact of upgrading to latest version: https://github.com/crivetechie/conftest/pull/1/files

[jalseth]

I think we should bump if the new version is more accurate according to the Terraform JSON syntax specification [1]. I haven't had time to review the spec in detail, but if you can confirm that the new output is aligned with the spec, feel free to open a PR to bump the dep.

[1] https://developer.hashicorp.com/terraform/language/syntax/json