resource count can't reference resource variable: <splat resource>

[mengesb]

It seems reasonable that I could do "${length(aws_eip.<name>.*.id)}" to return the count of elastic IP resources. This produces an error currently. I can successfully use this interpolation for outputs, but I cannot use it for other resource interpolations.

Further testing actually shows i might not be able to perform a length() operation on any splat... which is awful. Pretty darn sure this worked in 0.7.x series

Terraform Version

0.8.1

Affected Resource(s)

• aws_*
• count meta-variable?
• length() interpolation ?

Terraform Configuration Files

resource "aws_eip" "nat-eips" {
  count = "3"
  vpc = true
}
resource "aws_instance" "instances" {
  count = "${length(aws_eip.nat-eips.*.id)}"
}

Debug Output

2016/12/16 10:47:42 [INFO] Terraform version: 0.8.1
2016/12/16 10:47:42 [INFO] CLI args: []string{"/usr/local/Cellar/terraform/0.8.1/bin/terraform", "plan"}
2016/12/16 10:47:42 [DEBUG] Detected home directory from env var: /Users/user
2016/12/16 10:47:42 [DEBUG] Detected home directory from env var: /Users/user
2016/12/16 10:47:42 [DEBUG] Attempting to open CLI config file: /Users/user/.terraformrc
2016/12/16 10:47:42 [DEBUG] File doesn't exist, but doesn't need to. Ignoring.
2016/12/16 10:47:42 [DEBUG] Detected home directory from env var: /Users/user
module root: 1 error(s) occurred:

2016/12/16 10:47:42 [DEBUG] plugin: waiting for all plugin processes to complete...
* aws_instance.instance: resource count can't reference resource variable: aws_eip.chef-nat-eip.*.id

Panic Output

N/A

Expected Behavior

I should be able to use length() interpolation on the aws_eip resource in other count metavars of resources

Actual Behavior

terraform plan and terraform apply fails to run with the error:

* aws_instance.instance: resource count can't reference resource variable: aws_eip.chef-nat-eip.*.id

Steps to Reproduce

Please list the steps required to reproduce the issue, for example:

1. terraform plan

Important Factoids

N/A

References

[mitchellh]

Sorry, but this doesn't work and hasn't ever worked in recent memory. I tried versions 0.8.1, 0.7.13, 0.7.0, and 0.6.0 (whew!). The error message has gotten better over time, but the functionality has never worked.

There is a mega issue here at #3888 that we're hoping we can resolve with 0.9. I'll close as a dup of that.

[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 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.