Larger diff than expected generated when changing helm_release 'set' 'value'

[adcharre]

Terraform, Provider, Kubernetes and Helm Versions

Terraform version: v1.2.4
Provider version: v2.6.0
Kubernetes version: v1.23.6
Helm version: version.BuildInfo{Version:"v3.9.0", GitCommit:"7ceeda6c585217a19a1131663d8cd1f7d641b2a7", GitTreeState:"clean", GoVersion:"go1.17.5"}

Affected Resource(s)

• helm_release

Terraform Configuration Files

terraform {
  required_version = ">= 1.0.0"
  required_providers {
    kubernetes = {
      source  = "hashicorp/kubernetes"
      version = ">= 2.8.0"
    }
    helm = {
      source  = "hashicorp/helm"
      version = ">= 2.4.1"
    }
  }
}

provider "kubernetes" {
  config_path = "~/.kube/config"
}

provider "helm" {
  kubernetes {
    config_path = "~/.kube/config"
  }
}

variable "memory" {
  type = string
}

resource "helm_release" "test" {
    name = "test"
    repository = "https://coredns.github.io/helm"
    chart = "coredns"

    set {
      name = "replicaCount"
      value = "1"
    }

    set {
      name = "resources.requests.memory"
      value = var.memory
    }
}

Debug Output

NOTE: In addition to Terraform debugging, please set HELM_DEBUG=1 to enable debugging info from helm.

Terraform log and state file: https://gist.github.com/adcharre/120482e9f4d4bcb5641c49f6fb35f0f1

Panic Output

Steps to Reproduce

1. terraform apply -auto-approve -var memory=100Mi
2. terraform apply -auto-approve -var memory=120Mi
3. terraform apply -auto-approve -var memory=100Mi

Expected Behavior

On second and third apply, xxx and yyy would be a number.

helm_release.test: Refreshing state... [id=test]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # helm_release.test will be updated in-place
  ~ resource "helm_release" "test" {
        id                         = "test"
        name                       = "test"
        # (28 unchanged attributes hidden)

      - set {
          - name  = "resources.requests.memory" -> null
          - value = "xxxMi" -> null
        }
      + set {
          + name  = "resources.requests.memory"
          + value = "yyyMi"
        }
    }

Plan: 0 to add, 1 to change, 0 to destroy.
helm_release.test: Modifying... [id=test]
helm_release.test: Modifications complete after 1s [id=test]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

Actual Behavior

On second and third apply:

helm_release.test: Refreshing state... [id=test]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # helm_release.test will be updated in-place
  ~ resource "helm_release" "test" {
        id                         = "test"
        name                       = "test"
        # (27 unchanged attributes hidden)

      - set {
          - name  = "replicaCount" -> null
          - value = "1" -> null
        }
      + set {
          + name  = "replicaCount"
          + value = "1"
        }
      - set {
          - name  = "resources.requests.memory" -> null
          - value = "xxxMi" -> null
        }
      + set {
          + name  = "resources.requests.memory"
          + value = "yyyMi"
        }
    }

Plan: 0 to add, 1 to change, 0 to destroy.
helm_release.test: Modifying... [id=test]
helm_release.test: Modifications complete after 1s [id=test]

Apply complete! Resources: 0 added, 1 changed, 0 destroyed.

On the third apply the follow warning is also seen in the log:

2022-07-11T12:02:27.741+0100 [WARN]  Provider "registry.terraform.io/hashicorp/helm" produced an unexpected new value for helm_release.test during refresh.
      - .set: planned set element cty.ObjectVal(map[string]cty.Value{"name":cty.StringVal("replicaCount"), "type":cty.NullVal(cty.String), "value":cty.StringVal("1")}) does not correlate with any element in actual

This looks like it might therefore be related to #711
Examining the state file it is clear that the "type" value for the "replicaCount" is now set to null.

Important Factoids

References

• 'Provider produced inconsistent final plan' error after apply  #711

Community Note

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[peay]

I am also hitting this. I would argue that the expected behaviour should be

      ~ set {
           name  = "resources.requests.memory"
          ~ value = "xxxMi" -> "yyyMi"
        }

instead of still having a deletion and an addition for that changed value (i.e., when a single value is updated, I believe it should show as "update in-place")

edit: this issue might be a duplicate of #627 and #749

[iBrandyJackson]

Closing this issue as resolved with https://github.com/hashicorp/terraform-provider-helm/releases/tag/v2.8.0 - in PR #916

[github-actions]

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