allow one service_name entry for the name of current stack

Author: HarshadVilekar

terraform/modules/validators/stack_validators.tf

@@ -1,18 +1,20 @@
 # Copyright (c) 2023, Oracle and/or its affiliates.
 # Licensed under the Universal Permissive License v1.0 as shown at https://oss.oracle.com/licenses/upl.
+# This validation is applicable only for resource manager stacks. Not applicable for terraform CLI mode.
 
-# list all stacks in all states (active, deleted etc)
+# list all stacks in any state (active, deleted etc)
 data "oci_resourcemanager_stacks" "all_stacks_in_the_compartment" {
   compartment_id = var.compartment_id
 }
 
+# collect id of each stack
 locals {
   stack_list = data.oci_resourcemanager_stacks.all_stacks_in_the_compartment.stacks
   num_stacks = length(local.stack_list)
   stack_ids = [for stack in local.stack_list : { id = stack.id }]
 }
 
-# get details of each stack
+# get details of each stack from the list of stack_ids
 data "oci_resourcemanager_stack" "all_stacks" {
   count = local.num_stacks
   #Required
@@ -21,8 +23,10 @@ data "oci_resourcemanager_stack" "all_stacks" {
 
 locals {
   stack_variables = [for stack in data.oci_resourcemanager_stack.all_stacks : { variables = stack.variables }]
-  service_names_used_by_existing_stacks = [for stack_variables in local.stack_variables : lookup(stack_variables.variables, "service_name", "?service_name_attribute_not_found?")]
-  service_name_already_exists = contains(local.service_names_used_by_existing_stacks, var.service_name) ? true : false
-  service_name_already_exists_msg      = "WLSC-ERROR: The stack with the service_name [${var.service_name}] already exisits in the stack compartment. Try again with a different service name."
+  service_names_used_by_existing_stacks = [for stack_variables in local.stack_variables : lookup(stack_variables.variables, "service_name", "?_not_found_?")]
+  duplicate_service_names_list = [for service_name in local.service_names_used_by_existing_stacks : service_name if service_name == var.service_name]
+  # There will be always one entry for the name of the current stack. Set duplicate to true if there are more than one entries.
+  service_name_already_exists = length(local.duplicate_service_names_list) > 1 ? true : false
+  service_name_already_exists_msg      = "WLSC-ERROR: Another stack with the service_name [${var.service_name}] already exisits in the stack compartment. Try again with a different service name."
   validate_service_name_is_not_already_used = local.service_name_already_exists ? local.validators_msg_map[local.service_name_already_exists_msg] : null
 }