tfvars --output-file terraform.tfvars inserts comments which make output file invalid

[jonathanperret]

Describe the bug

When running terraform-docs tfvars --output-file terraform.tfvars to generate a variables file, terraform-docs inserts a <!-- BEGIN_TF_DOCS --> comment at the start of the output file (regardless of whether the output is requested in JSON or HCL), and a <!-- END_TF_DOCS --> line at the end, which make the variables file invalid.

I'd expect terraform-docs tfvars --output-file terraform.tfvars to generate the expected content without inserting comments before and after it.

How can we reproduce it?

• Enter an empty directory.
• Run terraform-docs tfvars --output-file terraform.tfvars hcl ., or terraform-docs tfvars --output-file terraform.tfvars.json json .. The output says terraform.tfvars[.json] updated successfully.
• Open the resulting terraform.tfvars[.json] file and observe that it contains HTML comments making it syntactically invalid.

Suggested workaround

Adding --output-mode replace --output-template '{{ .Content }}' to the command line correctly generates a well-formed variables file.

Environment information

• terraform-docs version: terraform-docs version v0.16.0 1f686b1 darwin/arm64
• OS : macOS 13.5.2