Check attributes order and separation

[janschumann]

My client would like to ensure the order and separation of attributes and blocks for specific resources for the sake of readability.

Examples

1. Variable attribute order

good

variable "example" {
  description = "description"
  type = string
  default = "default"
}

bad

variable "example" {
  type = string
  default = "default"
  description = "description"
}

2. Variable attribute separation

good

variable "example" {
  description = "description"
  type = string
  default = "default"
}

bad

variable "example" {
  description = "description"

  type = string

  default = "default"
}

3. Variable validation rule separation

good

variable "example" {
  description = "description"
  type = string
  default = "default"

  validation {
    error_message = "message"
    condition     = var.example
  }

  validation {
    error_message = "message2"
    condition     = var.example
  }
}

bad

variable "example" {
  description = "description"
  type = string
  default = "default"
  validation {
    error_message = "message"
    condition     = var.example
  }
  validation {
    error_message = "message2"
    condition     = var.example
  }
}

While writing a ruleset to report those kind of issues, I stumbled upon the following:

• The hcl.Range of a validation block always contains the same line as Start and End attribute, so that a check if there is an empty line between validation blocks is not possible. (As a workaround, I expand the validation block attributes and add +1 to the last attribute to find the end of the validation block)

• Empty lines between attributes are not reported
  Consider the following variable definition:

variable "example" {
  description = "description"

  type  = string
}

My check uses the hcl.Range.Start of the first attribute and the hcl.Range.End of the last attribute to emit the issue:

tflint 
1 issue(s) found:

Error: No empty line is expected between attributes (terraform_variable_attribute_separation)

  on variables.tf line 2:
   2:   description = "The name of this content rewrite policy."
   4:   type  = string

As you can see, the empty line (3) is ignored.

And as a result, no fixFunc func(f Fixer) error can be used to remove the empty line.

Wouldn't it be great to accomplish such a ruleset with a fix?

Here is the repo I am testing with: https://github.com/schumann-it/tflint-ruleset-terraform-ext

I would be happy if someone could share their thoughts!