terraform required_version prevents s3 remote backend initialization

[gevgev]

we have the following files in the folder:

backend.tf 
main.tf
vars.tf

The content for the backend.tf:

terraform {
    backend "s3" {
        bucket 		= "BUCKET_NAME"
        key 		= "KEY_PATH/s3.json"
        region 		= "us-east-1"

        lock 		= "true"
        encrypt		= "true"
        lock_table 	= "terraform_state_lock"
        acl		= "bucket-owner-full-control"
    }
}

The content for the main.tf (can be anything - important is the terraform required_version):

terraform {
  required_version = ">= 0.9.1"
}

resource "aws_s3_bucket" "terraform_state" {
  bucket = "${var.bucket_name}"

  versioning {
    enabled = true
  }

  lifecycle {
    prevent_destroy = true
  }
}

With these files above terraform init -backend=true still initializes to local state:

$ ./terraform init -backend=true /PATH_TO_PROJECT/s3
Initializing configuration from: "/PATH_TO_PROJECT/s3"...

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your environment. If you forget, other
commands will detect it and remind you to do so if necessary.

If we remove terraform required_version from main.tf, then we get the project backend properly configured to s3.

main.tf content (no terraform required_version):

resource "aws_s3_bucket" "terraform_state" {
  bucket = "${var.bucket_name}"

  versioning {
    enabled = true
  }

  lifecycle {
    prevent_destroy = true
  }
}

Execution output:

./terraform init -backend=true /PATH_TO_PROJECT/s3
Initializing configuration from: "PATH_TO_PROJECT/s3"...
Initializing the backend...


Successfully configured the backend "s3"! Terraform will automatically
use this backend unless the backend configuration changes.

Terraform has been successfully initialized!

You may now begin working with Terraform. Try running "terraform plan" to see
any changes that are required for your infrastructure. All Terraform commands
should now work.

If you ever set or change modules or backend configuration for Terraform,
rerun this command to reinitialize your environment. If you forget, other
commands will detect it and remind you to do so if necessary.

[mitchellh]

Notes: this is a bug in Terraform merge logic in config/append.go

[ghost]

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