fix handling default nulls in data objects

Author: kevcube

main.tf

@@ -361,7 +361,7 @@ resource "aws_cloudfront_monitoring_subscription" "this" {
 data "aws_cloudfront_cache_policy" "this" {
   for_each = toset([
     for v in concat([var.default_cache_behavior], var.ordered_cache_behavior) :
-    v.cache_policy_name if can(v.cache_policy_name)
+    v.cache_policy_name if can(v.cache_policy_name) && v.cache_policy_name != null
   ])
 
   name = each.key
@@ -370,7 +370,7 @@ data "aws_cloudfront_cache_policy" "this" {
 data "aws_cloudfront_origin_request_policy" "this" {
   for_each = toset([
     for v in concat([var.default_cache_behavior], var.ordered_cache_behavior) :
-    v.origin_request_policy_name if can(v.origin_request_policy_name)
+    v.origin_request_policy_name if can(v.origin_request_policy_name) && v.origin_request_policy_name != null
   ])
 
   name = each.key
@@ -379,7 +379,7 @@ data "aws_cloudfront_origin_request_policy" "this" {
 data "aws_cloudfront_response_headers_policy" "this" {
   for_each = toset([
     for v in concat([var.default_cache_behavior], var.ordered_cache_behavior) :
-    v.response_headers_policy_name if can(v.response_headers_policy_name)
+    v.response_headers_policy_name if can(v.response_headers_policy_name) && v.response_headers_policy_name != null
   ])
 
   name = each.key