Don't apply archival storageclass rule unless necessary

terraform/aws/buckets.tf

@@ -17,15 +17,21 @@ resource "aws_s3_bucket_lifecycle_configuration" "user_bucket_expiry" {
     }
   }
 
-  rule {
-    id     = "archival-storageclass"
-    status = each.value.delete_after != null ? "Enabled" : "Disabled"
+  dynamic "rule" {
+    # Only set up this rule if it will be enabled. Prevents unnecessary
+    # churn in terraform
+    for_each = each.value.archival_storageclass_after != null ? [1] : []
 
-    transition {
-      # Transition this to much cheaper object storage after a few days
-      days = each.value.archival_storageclass_after
-      # Glacier Instant is fast enough while also being pretty cheap
-      storage_class = "GLACIER_IR"
+    content {
+      id     = "archival-storageclass"
+      status = "Enabled"
+
+      transition {
+        # Transition this to much cheaper object storage after a few days
+        days = each.value.archival_storageclass_after
+        # Glacier Instant is fast enough while also being pretty cheap
+        storage_class = "GLACIER_IR"
+      }
     }
   }
 }