f - remove extra string allocations

Author: jkczyz

lightning/src/util/persist.rs

@@ -752,10 +752,10 @@ where
 	) -> chain::ChannelMonitorUpdateStatus {
 		const LEGACY_CLOSED_CHANNEL_UPDATE_ID: u64 = u64::MAX;
 		if let Some(update) = update {
-			let monitor_key = monitor_name.to_string();
 			let persist_update = update.update_id != LEGACY_CLOSED_CHANNEL_UPDATE_ID
 				&& update.update_id % self.maximum_pending_updates != 0;
 			if persist_update {
+				let monitor_key = monitor_name.to_string();
 				let update_name = UpdateName::from(update.update_id);
 				match self.kv_store.write(
 					CHANNEL_MONITOR_UPDATE_PERSISTENCE_PRIMARY_NAMESPACE,
@@ -781,6 +781,7 @@ where
 				// the new one in order to determine the cleanup range.
 				let maybe_old_monitor = match monitor.get_latest_update_id() {
 					LEGACY_CLOSED_CHANNEL_UPDATE_ID => {
+						let monitor_key = monitor_name.to_string();
 						self.read_monitor(&monitor_name, &monitor_key).ok()
 					},
 					_ => None,