Terraform: aws_lambda_function.vpc_config always detects a change when empty

[rochdev]

Terraform Version

0.8.2

Affected Resource(s)

aws_lambda_function

Terraform Configuration Files

# Only relevant parts shown

variable "subnet_ids" {
  default = []
}

variable "security_group_ids" {
  default = []
}

resource "aws_lambda_function" "lambda" {
  vpc_config {
    subnet_ids         = ["${var.subnet_ids}"]
    security_group_ids = ["${var.security_group_ids}"]
  }
}

Expected Behavior

Right after applying, terraform plan should not detect any change since there aren't any.

Actual Behavior

Right after applying, terraform plan detects a change in vpc_config. If you apply the change, terraform plan will still detect the same change over and over again.

Relevant part of the output:

-/+ module.auth.authorizer.authorizer_lambda.aws_lambda_function.lambda
    vpc_config.#:        "0" => "1" (forces new resource)
    vpc_config.0.vpc_id: "" => "<computed>"

Steps to Reproduce

1. terraform plan
2. terraform apply
3. repeat

References

Seem to be related:

• https://github.com/hashicorp/terraform/pull/6157
• https://github.com/hashicorp/terraform/pull/6191

[pgieser]

We've been seeing this behavior since 0.7.13.

[pgieser]

Anything happening here?

[danielwhite]

This is still happening in 0.9.4.

[hilaryhacksel]

This is still happening in 0.11.3. Any updates here?

[hashibot[bot]]

I'm going to lock this issue because it has been closed for _30 days_ ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.