fix

vpc-transit-gateway-association/README.md

@@ -31,6 +31,7 @@ This sets up the necessary transit gateway configuration for attaching a VPC wit
 | <a name="provider_aws.network_account"></a> [aws.network\_account](#provider\_aws.network\_account) | >= 3.66.0 |
 | <a name="provider_aws.peer"></a> [aws.peer](#provider\_aws.peer) | >= 3.66.0 |
 | <a name="provider_aws.self"></a> [aws.self](#provider\_aws.self) | >= 3.66.0 |
+| <a name="provider_null"></a> [null](#provider\_null) | >= 3.0 |
 
 ## Modules
 
@@ -50,6 +51,7 @@ This sets up the necessary transit gateway configuration for attaching a VPC wit
 | [aws_ec2_transit_gateway_route_table_propagation.vpc_self_own_rt](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ec2_transit_gateway_route_table_propagation) | resource |
 | [aws_ec2_transit_gateway_vpc_attachment.vpc_attachment](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ec2_transit_gateway_vpc_attachment) | resource |
 | [aws_route.gateway_ipv4](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/route) | resource |
+| [null_resource.vpc_attachment_exists](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource) | resource |
 | [aws_arn.current](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/arn) | data source |
 | [aws_arn.network_account](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/arn) | data source |
 | [aws_availability_zone.zone](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zone) | data source |

vpc-transit-gateway-association/routing.tf

@@ -37,6 +37,13 @@ data "aws_ec2_managed_prefix_list" "tgw_ipv4" {
   id       = each.key
 }
 
+resource "null_resource" "vpc_attachment_exists" {
+  triggers = {
+    vpc_attachment = one(aws_ec2_transit_gateway_vpc_attachment.vpc_attachment[*].id)
+  }
+}
+
+
 # pick the first prefix list found, either NAME or NAME.ipv4
 resource "aws_route" "gateway_ipv4" {
   for_each = var.transit_gateway_routing_type == "self" ? module.routing_attachment_ipv4[0].private_route_table_ids : {}
@@ -46,5 +53,5 @@ resource "aws_route" "gateway_ipv4" {
   destination_prefix_list_id = one([for k, v in data.aws_ec2_managed_prefix_list.tgw_ipv4 : k if v.address_family == "IPv4"])
   transit_gateway_id         = data.aws_ec2_transit_gateway.gateway_self.id
 
-  depends_on = [aws_ec2_transit_gateway_vpc_attachment.vpc_attachment]
+  depends_on = [null_resource.vpc_attachment_exists]
 }