Assert query's and route's final_value_msat are equal

Author: tnull

lightning/src/ln/outbound_payment.rs

@@ -875,7 +875,7 @@ impl OutboundPayments {
 			}
 		}
 
-		let route = router.find_route_with_id(
+		let mut route = router.find_route_with_id(
 			&node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 			Some(&first_hops.iter().collect::<Vec<_>>()), inflight_htlcs(),
 			payment_hash, payment_id,
@@ -885,6 +885,14 @@ impl OutboundPayments {
 			RetryableSendFailure::RouteNotFound
 		})?;
 
+		if let Some(route_route_params) = route.route_params.as_mut() {
+			if route_route_params.final_value_msat != route_params.final_value_msat {
+				debug_assert!(false,
+					"Routers are expected to return a route which includes the requested final_value_msat");
+				route_route_params.final_value_msat = route_params.final_value_msat;
+			}
+		}
+
 		let onion_session_privs = self.add_new_pending_payment(payment_hash,
 			recipient_onion.clone(), payment_id, keysend_preimage, &route, Some(retry_strategy),
 			Some(route_params.payment_params.clone()), entropy_source, best_block_height)
@@ -926,7 +934,7 @@ impl OutboundPayments {
 			}
 		}
 
-		let route = match router.find_route_with_id(
+		let mut route = match router.find_route_with_id(
 			&node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 			Some(&first_hops.iter().collect::<Vec<_>>()), inflight_htlcs(),
 			payment_hash, payment_id,
@@ -938,6 +946,15 @@ impl OutboundPayments {
 				return
 			}
 		};
+
+		if let Some(route_route_params) = route.route_params.as_mut() {
+			if route_route_params.final_value_msat != route_params.final_value_msat {
+				debug_assert!(false,
+					"Routers are expected to return a route which includes the requested final_value_msat");
+				route_route_params.final_value_msat = route_params.final_value_msat;
+			}
+		}
+
 		for path in route.paths.iter() {
 			if path.hops.len() == 0 {
 				log_error!(logger, "Unusable path in route (path.hops.len() must be at least 1");

lightning/src/util/test_utils.rs

@@ -124,6 +124,7 @@ impl<'a> Router for TestRouter<'a> {
 		if let Some((find_route_query, find_route_res)) = self.next_routes.lock().unwrap().pop_front() {
 			assert_eq!(find_route_query, *params);
 			if let Ok(ref route) = find_route_res {
+				assert_eq!(route.route_params.as_ref().unwrap().final_value_msat, find_route_query.final_value_msat);
 				let scorer = self.scorer.read().unwrap();
 				let scorer = ScorerAccountingForInFlightHtlcs::new(scorer, &inflight_htlcs);
 				for path in &route.paths {