Simplify conflicting restore_to_point_in_time attributes

main.tf

@@ -7,19 +7,6 @@ locals {
   is_regional_cluster      = var.cluster_type == "regional"
   is_serverless            = var.engine_mode == "serverless"
   ignore_admin_credentials = var.replication_source_identifier != "" || var.snapshot_identifier != null
-
-  # Only set one of `use_latest_restorable_time` and `restore_to_time` since they conflict.
-  # For backwards compatibility, `use_latest_restorable_time` defaults to true if both of these values are null.
-  restore_to_point_in_time_configuration = [for config in var.restore_to_point_in_time : {
-    source_cluster_identifier = config.source_cluster_identifier
-    restore_type              = config.restore_type
-    use_latest_restorable_time = (
-      config.use_latest_restorable_time == null && config.restore_to_time == null ?
-      true :
-      coalesce(config.use_latest_restorable_time, true)
-    )
-    restore_to_time = config.restore_to_time
-  }]
 }
 
 data "aws_partition" "current" {
@@ -163,11 +150,13 @@ resource "aws_rds_cluster" "primary" {
   }
 
   dynamic "restore_to_point_in_time" {
-    for_each = local.restore_to_point_in_time_configuration
+    for_each = var.restore_to_point_in_time
     content {
-      source_cluster_identifier  = restore_to_point_in_time.value.source_cluster_identifier
-      restore_type               = restore_to_point_in_time.value.restore_type
-      use_latest_restorable_time = restore_to_point_in_time.value.use_latest_restorable_time
+      source_cluster_identifier = restore_to_point_in_time.value.source_cluster_identifier
+      restore_type              = restore_to_point_in_time.value.restore_type
+      # use_latest_restorable_time and restore_to_time are mutually exclusive.
+      # If restore_to_time is given, then we ignore use_latest_restorable_time
+      use_latest_restorable_time = restore_to_point_in_time.value.restore_to_time != null ? null : restore_to_point_in_time.value.use_latest_restorable_time
       restore_to_time            = restore_to_point_in_time.value.restore_to_time
     }
   }

variables.tf

@@ -199,7 +199,7 @@ variable "restore_to_point_in_time" {
   type = list(object({
     source_cluster_identifier  = string
     restore_type               = optional(string, "copy-on-write")
-    use_latest_restorable_time = optional(bool, null)
+    use_latest_restorable_time = optional(bool, true)
     restore_to_time            = optional(string, null)
   }))
   default     = []