Cannot index into a list returned by a function in interpolation expressions

[wr0ngway]

Hi there,

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Terraform Version

Terraform v0.7.8

Affected Resource(s)

• core

Terraform Configuration Files

variable "small_list" {
  type = "list"
  default = [{x = "y"}]
}

variable "filler_list" {
  type = "list"
  default = [{}, {}, {}, {}]
}

output "out2" {
  value = "${concat(var.small_list, var.filler_list)[0]}"
  // also fails
  // value = "${list("1", "2")[0]}"
}

Debug Output

N/A

Panic Output

N/A

Expected Behavior

I should be able to get an item from a dynamically generated list

Actual Behavior

Error loading Terraform: Error loading config: Error loading /Users/mconway/workspace/terraform-test/lists/main.tf: Error reading config for output out2: parse error: syntax error

Steps to Reproduce

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

1. terraform apply

Important Factoids

Nope, pretty simple example

References

N/A

[apparentlymart]

This is one of the things #11704 aimed to address. Although that wasn't able to land in its current state it is still something I plan to address in future, though likely to be considered as part of a more holistic plan to fix some wrinkles in the design of Terraform's interpolation language.

[apparentlymart]

Hi again @wr0ngway!

That "holistic plan" I mentioned has now resulted in a new implementation of the configuration language in master, ready to be included in the forthcoming v0.12.0 release.

I tested the configuration you gave with the v0.12.0-alpha2 prerelease build, and it seems to indeed be working as expected:

$ terraform apply

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Outputs:

out2 = {}

Thanks for reporting this, and sorry for not keeping this issue updated.

[wr0ngway]

Cool, thanks!

[ghost]

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