Unresolvable data references can cause a merged tag set to be null #205
Description
It looks like using merge() can produce an empty map if any of its elements have a direct reference that can't be resolved at scan time. For example, given the following Terraform file:
# main.tf
data "aws_region" "current" {}
variable "tags" {
type = map(string)
default = {
VarTag1 = data.aws_region.current.name
}
}
locals {
tags = {
LocalTag1 = data.aws_region.current.name
}
}
resource "aws_s3_bucket" "ok1" {
bucket = "ok1"
tags = merge(
var.tags,
local.tags
)
}
resource "aws_s3_bucket" "ok2" {
bucket = "ok2"
tags = {
"ResourceTag1" = data.aws_region.current.name
}
}
resource "aws_s3_bucket" "bug1" {
bucket = "bug1"
tags = merge(
var.tags,
local.tags,
{
"ResourceTag1" = data.aws_region.current.name
}
)
}There are 3 buckets with tag definitions that refer to data.aws_region.current.name, which tfparse resolves to a null/empty value. The ok1 and ok2 buckets end up with tags that have null/empty values, but the bug1 bucket produces an entirely null set of tags.
Results of a tfparse.load_from_path() for this sample module
{
"aws_region": [
{
"__tfmeta": {
"filename": "main.tf",
"label": "aws_region",
"line_end": 1,
"line_start": 1,
"path": "data.aws_region.current",
"type": "data"
},
"id": "6b85d52d-5153-48bc-849e-2b8db532fb52"
}
],
"aws_s3_bucket": [
{
"__tfmeta": {
"filename": "main.tf",
"label": "aws_s3_bucket",
"line_end": 43,
"line_start": 33,
"path": "aws_s3_bucket.bug1",
"type": "resource"
},
"bucket": "bug1",
"id": "adb04e60-9d00-46a0-b876-a79be0925e40",
"tags": null
},
{
"__tfmeta": {
"filename": "main.tf",
"label": "aws_s3_bucket",
"line_end": 23,
"line_start": 16,
"path": "aws_s3_bucket.ok1",
"type": "resource"
},
"bucket": "ok1",
"id": "a0de7f46-546a-46b3-89a1-02a5906111f6",
"tags": {
"LocalTag1": null,
"VarTag1": null
}
},
{
"__tfmeta": {
"filename": "main.tf",
"label": "aws_s3_bucket",
"line_end": 31,
"line_start": 25,
"path": "aws_s3_bucket.ok2",
"type": "resource"
},
"bucket": "ok2",
"id": "8581a2e6-8016-4f4b-8885-0d56bb973d85",
"tags": {
"ResourceTag1": null
}
}
],
"locals": [
{
"__tfmeta": {
"filename": "main.tf",
"line_end": 14,
"line_start": 10,
"path": "locals"
},
"id": "6ac38550-c83e-4fa4-bc8c-04cc0303a257",
"tags": {
"LocalTag1": null
}
}
],
"variable": [
{
"__tfmeta": {
"filename": "main.tf",
"label": "tags",
"line_end": 8,
"line_start": 3,
"path": "variable.tags"
},
"default": {
"VarTag1": null
},
"id": "8ca4495d-36da-4dfc-bad0-cd78ff373fb7",
"type": null
}
]
}