Warn user if AWS IAM policy starts not with opening brace

[VladRassokhin]

Terraform Version

0.9.5

Affected Resource(s)

• aws_iam_role_policy
  And probably all other resources related to IAM policies

Terraform Configuration Files

resource "aws_iam_role_policy" "ec2_monitoring_lambda_basic_execution" {
  depends_on = [
    "aws_lambda_function.enable_ec2_monitoring"]
  role = "${aws_iam_role.enable_ec2_monitoring.id}"
  policy = <<EOF
  {
      "Version": "2012-10-17",
      "Statement": [
          {
              "Effect": "Allow",
              "Action": ["logs:CreateLogGroup"],
              "Resource": ["arn:aws:logs:${var.aws_region}:${data.aws_caller_identity.current.account_id}:*"]
          }
      ]
  }
  EOF
}

Note that << heredoc used, <<- fixes problem as leading indentation removed.

Actual Behavior

Error putting IAM role policy terraform-00548fa690bb6d77afd48870ec: MalformedPolicyDocument: The policy failed legacy parsing
        status code: 400,

Caused by leading spaces before opening brace ({) in policy definition

Expected Behavior

Validation should fail for such policies or Terraform should silently remove leading spaces
As validation, Terraform could do simple json validation of policies.

Steps to Reproduce

1. terraform apply

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.