Failed to update scaling policy: ValidationException: Target group

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Terraform CLI and Terraform AWS Provider Version

Terraform 12.0.6

provider.aws: version = "~> 3.21"
provider.local: version = "~> 2.0"
provider.template: version = "~> 2.2"
provider.tls: version = "~> 3.0"

Affected Resource(s)

aws_ecs_service

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

# Copy-paste your Terraform configurations here - for large Terraform configs,
# please use a service like Dropbox and share a link to the ZIP file. For
# security, you can also encrypt the files using our GPG public key: https://keybase.io/hashicorp

Debug Output

  # module.ecs_cluster.aws_ecs_service.portal must be replaced
+/- resource "aws_ecs_service" "web" {
        cluster                            = "arn:aws:ecs:ap-northeast-1:****:cluster/name_of_cluster"
        deployment_maximum_percent         = 150
        deployment_minimum_healthy_percent = 50
      ~ desired_count                      = 2 -> 3
        enable_ecs_managed_tags            = false
        health_check_grace_period_seconds  = 60
      ~ iam_role                           = "aws-service-role" -> (known after apply)
      ~ id                                 = "arn:aws:ecs:ap-northeast-1:****:service/name_of_cluster/name_of_service" -> (known after apply)
      + launch_type                        = (known after apply)
        name                               = "name_of_service"
      + platform_version                   = (known after apply)
      - propagate_tags                     = "NONE" -> null
        scheduling_strategy                = "REPLICA"
      - tags                               = {} -> null
      ~ task_definition                    = "name_of_task:28" -> (known after apply)
        wait_for_steady_state              = false
      - capacity_provider_strategy {
          - base              = 0 -> null
          - capacity_provider = "name_of_auto_scaling_group" -> null
          - weight            = 1 -> null
        }
      - deployment_controller {
          - type = "ECS" -> null
        }
      + load_balancer { # forces replacement
          + container_name   = "name_of_container"
          + container_port   = 8080
          + target_group_arn = "arn:aws:elasticloadbalancing:ap-northeast-1:****:targetgroup/name_of_target_group/****"
        }
      - load_balancer { # forces replacement
          - container_name   = "name_of_container" -> null
          - container_port   = 8080 -> null
          - target_group_arn = "arn:aws:elasticloadbalancing:ap-northeast-1:***:targetgroup/name_of_target_group/****" -> null
        }
        ordered_placement_strategy {
            field = "attribute:ecs.availability-zone"
            type  = "spread"
        }
        ordered_placement_strategy {
            field = "instanceId"
            type  = "spread"
        }
        placement_constraints {
            type = "distinctInstance"
        }
    }

Panic Output

Error: InvalidParameterException: Creation of service was not idempotent. "name_of_ecs_service"

Error: Failed to update scaling policy: ValidationException: Target group target_group_name is not attached to resource name_of_ecs_service

Expected Behavior

Terraform should update ecs service object in aws with terraform apply

Actual Behavior

Terraform trying to create new ecs service before delete but still failing terraform apply

Steps to Reproduce

terraform apply

hashicorp / terraform-provider-aws

Failed to update scaling policy: ValidationException: Target group #16888