apparentlymart
commented
4 years ago Hi @mkielar! Sorry for this odd behavior, and thanks for the straightforward reproduction case.
I think you've hit the same underlying bug as hashicorp/terraform#24699 here. I believe this is actually an interaction between two different bugs:
- The HCL interpreter's handling of
...fails with this error when it's given an argument whose type is not decidable yet. The normal cause of that is when it's a resource output whose type will not be decided until the apply step, but that doesn't apply in your case and so that brings us to the other bug... - ...for some reason I've not yet determined, the
concatfunction seems to be indicating that it cannot predict its result type, and thus triggering the above described behavior.
The first of the bugs above applies to both this one and hashicorp/terraform#24699. The second one is unique to this particular issue, though fixing the first one would make the second one less important because it would change from being an error to just producing incomplete type information that could cause downstream validation to be skipped.
I think the fix over in HCL would be to add a new case to the switch statement that returns this error for if expandVal.Type() is cty.DynamicPseudoType, which is what it would return if the type isn't known yet. In that case, the function should immediately return cty.DynamicVal, diags and not attempt to execute the function yet. That will then allow the initial validation to succeed, so that later on the function call can be attempted again with full type information and produce the actual result.
ghost
Terraform Version
Terraform Configuration Files
Debug Output
Crash Output
Expected Behavior
cidrsubnetsshould return a list of 9 subnets.Actual Behavior
Calling
terraform validateorterraform applyends up with error message like this:Steps to Reproduce
terraform validateterraform applyalso fails.Additional Context
I'm converting a
listof strings into alistof numbers. Then, I'mconcatenating three lists of numbers, so that they make a biggerlistof numbers. Then I'm passing the longlistof numbers asnumbitstocidrsubnetsand expanding it, ascidrsubnetsdoes not accept the list by itself.If I don't expand it - i.e. i use:
i get following error with
terraform apply:So it sees it's a tuple, but then refuses to do the expansion. Also, I fund this terraform module: https://github.com/hashicorp/terraform-cidr-subnets/blob/master/main.tf where it follows similar approach, but with variables instead of locals. I tried it, and then it passes validation correctly. Looks like terraform fails to infer type of a local value in some cases (expansion) but it can infer it in other cases (when I don'd attempt expansion it says it's a tuple).
References