On initial send retries, avoid previously failed scids

Previously, we could have tried the same failed channels over and over until
retries are exhausted.

Author: valentinewallace

lightning/src/ln/outbound_payment.rs

@@ -732,8 +732,8 @@ impl OutboundPayments {
 
 	fn handle_pay_route_err<R: Deref, NS: Deref, ES: Deref, IH, SP, L: Deref>(
 		&self, err: PaymentSendFailure, payment_id: PaymentId, payment_hash: PaymentHash, route: Route,
-		route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>, inflight_htlcs: &IH,
-		entropy_source: &ES, node_signer: &NS, best_block_height: u32, logger: &L,
+		mut route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
+		inflight_htlcs: &IH, entropy_source: &ES, node_signer: &NS, best_block_height: u32, logger: &L,
 		pending_events: &Mutex<Vec<events::Event>>, send_payment_along_path: &SP,
 	)
 	where
@@ -747,11 +747,11 @@ impl OutboundPayments {
 	{
 		match err {
 			PaymentSendFailure::AllFailedResendSafe(errs) => {
-				Self::push_payment_path_failed_evs(payment_id, payment_hash, route.paths, errs.into_iter().map(|e| Err(e)), pending_events);
+				Self::push_payment_path_failed_evs(payment_id, payment_hash, Some(&mut route_params), route.paths, errs.into_iter().map(|e| Err(e)), pending_events);
 				self.retry_payment_internal(payment_id, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, logger, pending_events, send_payment_along_path);
 			},
 			PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, .. } => {
-				Self::push_payment_path_failed_evs(payment_id, payment_hash, route.paths, results.into_iter(), pending_events);
+				Self::push_payment_path_failed_evs(payment_id, payment_hash, None, route.paths, results.into_iter(), pending_events);
 				// Some paths were sent, even if we failed to send the full MPP value our recipient may
 				// misbehave and claim the funds, at which point we have to consider the payment sent, so
 				// return `Ok()` here, ignoring any retry errors.
@@ -763,7 +763,7 @@ impl OutboundPayments {
 				// initial HTLC-Add messages yet.
 			},
 			PaymentSendFailure::PathParameterError(results) => {
-				Self::push_payment_path_failed_evs(payment_id, payment_hash, route.paths, results.into_iter(), pending_events);
+				Self::push_payment_path_failed_evs(payment_id, payment_hash, None, route.paths, results.into_iter(), pending_events);
 				self.abandon_payment(payment_id, pending_events);
 			},
 			PaymentSendFailure::ParameterError(e) => {
@@ -775,7 +775,8 @@ impl OutboundPayments {
 	}
 
 	fn push_payment_path_failed_evs<I: ExactSizeIterator + Iterator<Item = Result<(), APIError>>>(
-		payment_id: PaymentId, payment_hash: PaymentHash, paths: Vec<Vec<RouteHop>>, path_results: I,
+		payment_id: PaymentId, payment_hash: PaymentHash,
+		mut route_params: Option<&mut RouteParameters>, paths: Vec<Vec<RouteHop>>, path_results: I,
 		pending_events: &Mutex<Vec<events::Event>>
 	) {
 		let mut events = pending_events.lock().unwrap();
@@ -785,7 +786,11 @@ impl OutboundPayments {
 				let failed_scid = if let APIError::InvalidRoute { .. } = e {
 					None
 				} else {
-					Some(path[0].short_channel_id)
+					let scid = path[0].short_channel_id;
+					if let Some(ref mut params) = route_params {
+						params.payment_params.previously_failed_channels.push(scid);
+					}
+					Some(scid)
 				};
 				events.push(events::Event::PaymentPathFailed {
 					payment_id: Some(payment_id),

lightning/src/ln/payment_tests.rs

@@ -2196,9 +2196,11 @@ fn immediate_retry_on_failure() {
 	route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
 	route.paths[0][0].fee_msat = 50_000_000;
 	route.paths[1][0].fee_msat = 50_000_001;
+	let mut pay_params = route_params.payment_params.clone();
+	pay_params.previously_failed_channels.push(chans[0].short_channel_id.unwrap());
 	nodes[0].router.expect_find_route(RouteParameters {
-			payment_params: route_params.payment_params.clone(),
-			final_value_msat: amt_msat, final_cltv_expiry_delta: TEST_FINAL_CLTV
+			payment_params: pay_params, final_value_msat: amt_msat,
+			final_cltv_expiry_delta: TEST_FINAL_CLTV
 		}, Ok(route.clone()));
 
 	nodes[0].node.send_payment_with_retry(payment_hash, &Some(payment_secret), PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();