Update main.tf

Author: nsimmonds

main.tf

@@ -25,7 +25,7 @@ resource "aws_lambda_function" "this" {
 
   lifecycle {
     precondition {
-      condition     = var.create_role && var.lambda_role != []
+      condition     = !var.create_role || var.create_role && var.lambda_role == ""
       error_message = "The 'create_role' and 'lambda_role' variables should not be used together. When creating a role, use 'role_name' to set the name."
       # The lambda_role variable should only be used to attach a pre-existing role, and will do nothing
       #    if create_role is true.