terraform_deprecated_index.md

terraform_deprecated_index

Disallow legacy dot index syntax.

This rule is enabled by "recommended" preset.

Example

locals {
  list  = ["a", "b", "c"]
  value = list.0 
}

$ tflint
1 issue(s) found:

Warning: List items should be accessed using square brackets (terraform_deprecated_index)

  on example.tf line 3:
   3:   value = list.0

Reference: https://github.com/terraform-linters/tflint-ruleset-terraform/blob/v0.1.0/docs/rules/terraform_deprecated_index.md

locals {
  list  = [{a = "b"}, {a = "c"}]
  value = list.*.a 
}

$ tflint
1 issue(s) found:

Warning: List items should be accessed using square brackets (terraform_deprecated_index)

  on example.tf line 3:
   3:   value = list.*.a

Reference: https://github.com/terraform-linters/tflint-ruleset-terraform/blob/v0.1.0/docs/rules/terraform_deprecated_index.md

Why

Terraform supports traditional square brackets for accessing list items by index or using the splat operator (*). However, for backward compatibility, Terraform continues to support accessing list items with the dot syntax normally used for attributes. While Terraform does not print warnings for this syntax, it is no longer documented and its use is discouraged.

• Legacy Splat Expressions

How To Fix

Switch to the square bracket syntax when accessing items in list, including resources that use count.

Example:

locals {
  list  = [{a = "b}, {a = "c"}]
  value = list.*.a
}

Change this to:

locals {
  list  = [{a = "b}, {a = "c"}]
  value = list[*].a
}