Security Groups with name or name_prefix starting with "terraform-" get recreated every time

[crubier]

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Terraform CLI and Terraform AWS Provider Version

• terraform v1.12 and up
• terraform-provider-aws v2.50 and up

Affected Resource(s)

• aws_security_group
• potentially any other resource that uses the name / name_prefix API pattern

Terraform Configuration Files

Minimum reproduction:

resource "aws_security_group" "foobar" {
  count       = 1
  name_prefix = "terraform-baz"
  description = "Security group."
  vpc_id      = var.vpc_id
}

This is used for example in terraform-aws-eks in two places:

• https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/workers.tf#L316
• https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/cluster.tf#L80

Debug Output

Panic Output

Expected Behavior

• First apply: Create the security group
• Subsequent apply: Nothing to change

Actual Behavior

• First apply: Create the security group
• Subsequent apply: Recreate the security group

+/- resource "aws_security_group" "foobar" {
    ...
     + name_prefix            = "terraform-baz" # forces replacement
  }

Steps to Reproduce

1. terraform apply

Important Factoids

References

• This is very related to this comment. Same cause, different effect SecurityGroup: Unintentional destroy/creation of same resource with long names #14898 (comment)

• This is caused by this line of the current project

  terraform-provider-aws/aws/internal/naming/naming.go

  Line 58 in e208508

  if HasResourceUniqueIdPrefix(name) {

• The prefix is defined there https://github.com/hashicorp/terraform-plugin-sdk/blob/651b26a663d34daed50d135ddd25e170ff6c6aae/helper/resource/id.go#L10

• Big boss told me to open this issue :-) https://twitter.com/mitchellh/status/1347375993057464322?s=20

[bflad]

Thank you for reporting this issue, @crubier, as this is certainly unexpected behavior. Please note that the naming package is currently only in use in two resources right now with this functionality, so these resources should be the only ones affected at the moment:

• aws_cloudwatch_event_rule
• aws_security_group

The fix in this case should be fairly straightforward and I will try to get that submitted along with covering testing (and contributing guide documentation) later today.

[bflad]

Pull request submitted here: #17030

[ghost]

This has been released in version 3.27.0 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 for triage. Thanks!

[ghost]

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 feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!