[Bug]: unexpected plan diff on aws_lb_listener when upgrading from 5.34.0 to 5.35.0

[jrobison-sb]

Terraform Core Version

v1.6.6

AWS Provider Version

5.35.0

Affected Resource(s)

• aws_lb_listener

Expected Behavior

I should be able to upgrade from provider 5.34.0 to provider 5.35.0 without any unexpected plan diffs on my existing resources.

Actual Behavior

I get unexpected plan diffs on aws_lb_listener resources when upgrading from provider 5.34.0 to provider 5.35.0.

Relevant Error/Panic Output Snippet

No response

Terraform Configuration Files

resource "aws_lb_listener" "http" {
  load_balancer_arn = aws_lb.foo.arn
  port              = "80"
  protocol          = "HTTP"

  default_action {
    target_group_arn = aws_lb_target_group.foo.arn

    type = "redirect"

    redirect {
      port        = "443"
      protocol    = "HTTPS"
      status_code = "HTTP_301"
    }
  }

  tags = {
    Name       = "http"
  }
}

Steps to Reproduce

1. Use provider 5.34.0 and create the aws_lb_listener resource seen in the provided HCL.
2. Run a terraform plan after creating the aws_lb_listener and see that there are no diffs in the plan.
3. Upgrade to provider 5.35.0
4. Run another terraform plan and see diffs like this:

  # module.production_application.aws_lb_listener.http will be updated in-place
~ resource "aws_lb_listener" "http" {
        id                = "arn:aws:elasticloadbalancing:us-east-1:1234567890:listener/app/production-containers/516ae9a008e4e100/6cabefb4163ad035"
        tags              = {
            "Name"       = "http"
        }
        # (5 unchanged attributes hidden)

      ~ default_action {
          + target_group_arn = "arn:aws:elasticloadbalancing:us-east-1:1234567890:targetgroup/tf-20181027131523749800000002/52249f311b1188f3"
            # (2 unchanged attributes hidden)

            # (1 unchanged block hidden)
        }

      - timeouts {}
    }

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

#35583

Would you like to implement a fix?

No

[github-actions]

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[jrobison-sb]

@gdavison thanks for looking at this. Since your PR mentioned "invalid attributes", I went back and checked if my attributes seen in the HCL above were actually valid, which they aren't.

resource "aws_lb_listener" "http" {
  load_balancer_arn = aws_lb.foo.arn
  port              = "80"
  protocol          = "HTTP"

  default_action {
    target_group_arn = aws_lb_target_group.foo.arn # NOT VALID BECAUSE I"M DOING A REDIRECT

    type = "redirect"

    redirect {
      port        = "443"
      protocol    = "HTTPS"
      status_code = "HTTP_301"
    }
  }

  tags = {
    Name       = "http"
  }
}

I was able to fix my HCL and remove the invalid attributes. So I personally no longer need the PR linked here, though I also have no objection to that PR if you still think it adds value.

I'll let you decide if this ticket should stay open or not. Feel free to close it if you like.

Thanks again for your attention to this and for helping me clean up my code a bit.

[github-actions]

This functionality has been released in v5.36.0 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]

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.