aws_batch_job_definition with empty env var generates unexpected diff on each tf apply (guaranteed reproduction😉)

[Veetaha]

Terraform Core Version

1.3.0

AWS Provider Version

4.31.0

Affected Resource(s)

• aws_batch_job_definition

Expected Behavior

There is no diff generated when doing tf apply if there were no changes to the resource at all.

Actual Behavior

tf apply generates a diff:

$ tf apply
aws_batch_job_definition.blackjack: Refreshing state... [id=arn:aws:batch:us-east-2:{REDACTED_ACCOUNT_ID}:job-definition/blackjack:3]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # aws_batch_job_definition.blackjack must be replaced
-/+ resource "aws_batch_job_definition" "blackjack" {
      ~ arn                   = "arn:aws:batch:us-east-2:{REDACTED_ACCOUNT_ID}:job-definition/blackjack:3" -> (known after apply)
      ~ container_properties  = jsonencode(
          ~ {
              - command                      = [] -> null
              ~ environment                  = [
                  + {
                      + name  = "FOO"
                      + value = ""
                    },
                    {
                        name  = "BAR"
                        value = "filled"
                    },
                ]
              - fargatePlatformConfiguration = {
                  - platformVersion = "LATEST"
                } -> null
              - mountPoints                  = [] -> null
              - secrets                      = [] -> null
              - ulimits                      = [] -> null
              - volumes                      = [] -> null
                # (4 unchanged elements hidden)
            } # forces replacement
        )
      ~ id                    = "arn:aws:batch:us-east-2:{REDACTED_ACCOUNT_ID}:job-definition/blackjack:3" -> (known after apply)
        name                  = "blackjack"
      - parameters            = {} -> null
      ~ revision              = 3 -> (known after apply)
        tags                  = {
            "elastio:resource" = "true"
        }
        # (4 unchanged attributes hidden)
    }

Plan: 1 to add, 0 to change, 1 to destroy.

Terraform Configuration Files

resource "aws_batch_job_definition" "blackjack" {
  name                  = "blackjack"
  type                  = "container"
  platform_capabilities = ["FARGATE"]
  container_properties  = <<JOB_DEFINITION
  {
    "image": "public.ecr.aws/elastio-dev/elastio-bg-job:0.19.21-amd64",
    "environment": [
        { "name": "FOO", "value": "" },
        { "name": "BAR", "value": "filled" }
    ],
    "jobRoleArn": "{REDACTED}",
    "executionRoleArn": "{REDACTED},
    "resourceRequirements": [
      { "type": "VCPU", "value": "4" },
      { "type": "MEMORY", "value": "12288" }
    ]
  }
  JOB_DEFINITION

  tags = {
    "elastio:resource" = "true"
  }
}

Steps to Reproduce

1. Copy-paste the terraform configuration file above to main.tf
2. Insert valid job role arn and execution role arn in places for redacted fields.
3. tf init
4. tf apply -auto-approve
5. tf apply, here you will see that there is a diff

Debug Output

I wouldn't like to share the TF_LOG=debug, since it may contain sensitive information. The problem is easily reproducible, so it's not very important.

[github-actions]

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[github-actions]

This functionality has been released in v4.58.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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