Inconsistent behaviour for Provider version numbers when root module only calls modules.

[rquadling]

Describe the bug

We have multiple repos for different microservices and all of them use pre-commit with terraform-docs setup as:

  - repo: https://github.com/antonbabenko/pre-commit-terraform
    rev: v1.83.5
    hooks:
      - id: terraform_fmt
      - id: terraform_validate
      - id: terraform_docs
        args:
          - --hook-config=--path-to-file=README.md
          - --hook-config=--add-to-existing-file=true
          - --hook-config=--create-file-if-not-exist=true

No special options regarding the overriding of terraform-docs.

Our provider setups are per project, and will include different providers, but all will be AWS at v5:

terraform {
  required_version = ">= 1.3.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5"
    }
  }
}

The lock file is also present and always has a single version for the provider:

provider "registry.terraform.io/hashicorp/aws" {
  version     = "5.27.0"
  constraints = "~> 5.0"
  hashes = [
    ...
  ]
}

But, depending upon the repo, the output in the README is different.

This project is TF and AWS only with root tf files managing resources.

## Requirements

| Name | Version |
|------|---------|
| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.3.0 |
| <a name="requirement_aws"></a> [aws](#requirement\_aws) | ~> 5 |

## Providers

| Name | Version |
|------|---------|
| <a name="provider_aws"></a> [aws](#provider\_aws) | 5.27.0 |

This project is uses the same providers, but all in modules. Nothing is in the root module.

## Requirements

| Name | Version |
|------|---------|
| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.3.0 |
| <a name="requirement_aws"></a> [aws](#requirement\_aws) | ~> 5 |

## Providers

No providers.

I've tried with and without --lockfile=true (both on the terraform-docs command line and via pre-commit's - --arg=--lockfile=true).

How can we reproduce it?

Several files are needed. Hopefully enough here to make sense.

.terraform-version (used by tfenv if you are using that - not required otherwise)

1.6.3

.terraform.lock.hcl (I'm not sure how much of the content of this file is required, but here it is)

# This file is maintained automatically by "terraform init".
# Manual edits may be lost in future updates.

provider "registry.terraform.io/hashicorp/aws" {
  version     = "5.27.0"
  constraints = "~> 5.0"
  hashes = [
    "h1:7tlujJ/5W0N3haoGhaoZ4fQ6mTXO5JHSQq7gKvwJ9SY=",
    "h1:NM9c2aiYhbCGX4CcBqNEgAqzMKeY3SQvy+l1lB3GygI=",
    "h1:t67hg2gITLxCfO3sewnrqwExFEnM5VVBhnANKLMWy/w=",
    "zh:096b4f356a8518d601334cb1765c1d317494aefbdd6de089420fc68a3facedf0",
    "zh:0c46222baa052b72f077dfed4f9d06b4c71b8d9fdf0b6c4ab2a8b46a41baeb7a",
    "zh:1339deb2384dfef8b7252fbd76784c512cd74f83bb8337cba96776107a1d904c",
    "zh:18c47662a6d9c8f96b6d7cbf6fca739526123fc83f4b2bcee68e7f8774d4078c",
    "zh:2a323401ca7c752749c9b8dbc2a3f587eebfa49344fde704ae9e692bfdd3b9ee",
    "zh:36f6f9b94bc04dcba5e16038cfbedae24fcb035e5a546cf81c8f7632d9dbc3ca",
    "zh:411d884b8f71be03fedcfcb82ead85871647e3dbf38f7264ce3b3aa84be6ead5",
    "zh:47b185810dec758ca7cdeb5d30baaf8119c346753378e72285d152962ec43855",
    "zh:48b896c8c1aa46f536f398d1b87ec6b5141aa569924ee17f5ee5a928effcd554",
    "zh:6560e1ae0f6a3bf55b2d1d8267d766611c38387a17da19bde66f89412dbf6261",
    "zh:9b12af85486a96aedd8d7984b0ff811a4b42e3d88dad1a3fb4c0b580d04fa425",
    "zh:aa518bd94f94a2e38f2d6ffc25da08fc4fd2b2f38d77becd3c1503720c304584",
    "zh:d8d90bb74c87c8e368ec66f3d214828ab4c24bb70e764bc888207a4ed5783550",
    "zh:da3c76e28342e1af7e06ea3d31a8e76cc6bf0070877beaf58c088008f61c48f9",
    "zh:f403fa79a3d612be7ed4fca9d3df6fb30bc7de890ecbafe7881f38bf9b07c382",
  ]
}

.pre-commit-config.yaml

repos:
  - repo: https://github.com/antonbabenko/pre-commit-terraform
    rev: v1.83.5
    hooks:
      - id: terraform_fmt
      - id: terraform_validate
        exclude: modules
      - id: terraform_docs
        args:
          - --hook-config=--path-to-file=README.md
          - --hook-config=--add-to-existing-file=true
          - --hook-config=--create-file-if-not-exist=true

make_error.tf

terraform {
  required_version = ">= 1.3.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5"
    }
  }
}

provider "aws" {
  region = "eu-west-1"
}

module "readme_error_maker" {
  source = "./modules/readme_error_maker"
}

output "user" {
  description = "User"
  value       = module.readme_error_maker.user
}

modules/readme_error_maker/main.tf

terraform {
  required_version = ">= 1.3.0"
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5"
    }
  }
}

data "aws_caller_identity" "current" {}

output "user" {
  description = "The current user's ARN"
  value       = data.aws_caller_identity.current.arn
}

Once all those are in place, run pre-commit run --all

$ pre-commit run --all
Terraform fmt............................................................Passed
Terraform validate.......................................................Passed
Terraform docs...........................................................Passed

And the following README.md's are created:

README.md

# readme_error

<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
## Requirements

| Name | Version |
|------|---------|
| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.3.0 |
| <a name="requirement_aws"></a> [aws](#requirement\_aws) | ~> 5 |

## Providers

No providers.

## Modules

| Name | Source | Version |
|------|--------|---------|
| <a name="module_readme_error_maker"></a> [readme\_error\_maker](#module\_readme\_error\_maker) | ./modules/readme_error_maker | n/a |

## Resources

No resources.

## Inputs

No inputs.

## Outputs

| Name | Description |
|------|-------------|
| <a name="output_user"></a> [user](#output\_user) | User |
<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

and modules/readme_error_maker/README.md

# readme_error_maker

<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
## Requirements

| Name | Version |
|------|---------|
| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.3.0 |
| <a name="requirement_aws"></a> [aws](#requirement\_aws) | ~> 5 |

## Providers

| Name | Version |
|------|---------|
| <a name="provider_aws"></a> [aws](#provider\_aws) | ~> 5 |

## Modules

No modules.

## Resources

| Name | Type |
|------|------|
| [aws_caller_identity.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) | data source |

## Inputs

No inputs.

## Outputs

| Name | Description |
|------|-------------|
| <a name="output_user"></a> [user](#output\_user) | The current user's ARN |
<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

If I remove both README.mds, and run terraform-docs markdown table . --recursive --output-file README.md instead:

$ terraform-docs markdown table . --recursive --output-file README.md
README.md updated successfully
modules/readme_error_maker/README.md updated successfully

then the only difference is the block markers are now <-- BEGIN_TF_DOCS --> / <-- END_TF_DOCS --> and no heading line. The rest of the content is the same.

Environment information

$ terraform-docs --version
terraform-docs version v0.16.0 darwin/amd64

$ go version
go version go1.18.4 darwin/amd64

All on MacOS. NOTE: I'm not compiling my own version of terraform-docs.

[rquadling]

OOI, adding a single output in the root module tf (make_error.tf)

data "aws_caller_identity" "current" {}

output "account" {
  description = "The account ID"
  value       = data.aws_caller_identity.current.account_id
}

"solves" the problem with

## Providers

| Name | Version |
|------|---------|
| <a name="provider_aws"></a> [aws](#provider\_aws) | 5.27.0 |

now being present in the root README.md.