Terraform 0.13 validate crashes on Custom Validation Rules when error_message contains an accent

[xsaamiir]

Terraform Version

Terraform v0.13.0-beta1

Terraform Configuration Files

variable "email_address" {
  type    = string
  default = "Application <[email protected]>"
  validation {
    condition     = can(regex(".{4,20} <[email protected]>", var.email_address))
    error_message = "A sentence with an accent é."
  }
}

Debug Output

https://gist.github.com/sharkyze/b3db1dd702518f2ad7d067b1a469f3f8

Crash Output

https://gist.github.com/sharkyze/b3db1dd702518f2ad7d067b1a469f3f8

Expected Behavior

Not to crash

Actual Behavior

Terraform crashes

Steps to Reproduce

$ mkdir tf-crash && cd tf-crash
$ cat <<END >main.tf
variable "email_address" {
  type    = string
  default = "Application <[email protected]>"
  validation {
    condition     = can(regex(".{4,20} <[email protected]>", var.email_address))
    error_message = "A sentence with an accent é."
  }
}
END
$ terraform validate

Additional Context

References

The error comes from the following line due to the accent:

terraform/configs/named_values.go

Line 402 in ff4ea04

last := runes[len(s)-1]

I was able to fix this bug by making the following changes: https://github.com/hashicorp/terraform/compare/master...sharkyze:configs/fix-looksLikeSentences-index-out-of-range?expand=0.

I would be happy to send a PR if you are ok with the changes

[danieldreier]

Thanks @sharkyze! I really, really appreciate you testing out 0.13!

I have reproduced this issue on 0.13 beta 1.

[ghost]

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