[rust-lightning] / lightning / src / ln / payment_tests.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

//! Tests that test the payment retry logic in ChannelManager, including various edge-cases around
//! serialization ordering between ChannelManager/ChannelMonitors and ensuring we can still retry
//! payments thereafter.

use crate::chain::{ChannelMonitorUpdateStatus, Confirm, Listen, Watch};
use crate::chain::channelmonitor::{ANTI_REORG_DELAY, HTLC_FAIL_BACK_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
use crate::sign::EntropySource;
use crate::chain::transaction::OutPoint;
use crate::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PathFailure, PaymentFailureReason};
use crate::ln::channel::EXPIRE_PREV_CONFIG_TICKS;
use crate::ln::channelmanager::{BREAKDOWN_TIMEOUT, ChannelManager, MPP_TIMEOUT_TICKS, MIN_CLTV_EXPIRY_DELTA, PaymentId, PaymentSendFailure, IDEMPOTENCY_TIMEOUT_TICKS, RecentPaymentDetails, RecipientOnionFields, HTLCForwardInfo, PendingHTLCRouting, PendingAddHTLCInfo};
use crate::ln::features::Bolt11InvoiceFeatures;
use crate::ln::{msgs, PaymentSecret, PaymentPreimage};
use crate::ln::msgs::ChannelMessageHandler;
use crate::ln::outbound_payment::Retry;
use crate::routing::gossip::{EffectiveCapacity, RoutingFees};
use crate::routing::router::{get_route, Path, PaymentParameters, Route, Router, RouteHint, RouteHintHop, RouteHop, RouteParameters, find_route};
use crate::routing::scoring::ChannelUsage;
use crate::util::test_utils;
use crate::util::errors::APIError;
use crate::util::ser::Writeable;
use crate::util::string::UntrustedString;

use bitcoin::network::constants::Network;

use crate::prelude::*;

use crate::ln::functional_test_utils::*;
use crate::routing::gossip::NodeId;
#[cfg(feature = "std")]
use {
        crate::util::time::tests::SinceEpoch,
        std::time::{SystemTime, Instant, Duration}
};

#[test]
fn mpp_failure() {
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        let chan_1_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
        let chan_2_id = create_announced_chan_between_nodes(&nodes, 0, 2).0.contents.short_channel_id;
        let chan_3_id = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents.short_channel_id;
        let chan_4_id = create_announced_chan_between_nodes(&nodes, 2, 3).0.contents.short_channel_id;

        let (mut route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[3], 100000);
        let path = route.paths[0].clone();
        route.paths.push(path);
        route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
        route.paths[0].hops[0].short_channel_id = chan_1_id;
        route.paths[0].hops[1].short_channel_id = chan_3_id;
        route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
        route.paths[1].hops[0].short_channel_id = chan_2_id;
        route.paths[1].hops[1].short_channel_id = chan_4_id;
        send_along_route_with_secret(&nodes[0], route, &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], 200_000, payment_hash, payment_secret);
        fail_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_hash);
}

#[test]
fn mpp_retry() {
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        let (chan_1_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 0, 1);
        let (chan_2_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 0, 2);
        let (chan_3_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 1, 3);
        let (chan_4_update, _, chan_4_id, _) = create_announced_chan_between_nodes(&nodes, 3, 2);
        // Rebalance
        send_payment(&nodes[3], &vec!(&nodes[2])[..], 1_500_000);

        let amt_msat = 1_000_000;
        let (mut route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[3], amt_msat);
        let path = route.paths[0].clone();
        route.paths.push(path);
        route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
        route.paths[0].hops[0].short_channel_id = chan_1_update.contents.short_channel_id;
        route.paths[0].hops[1].short_channel_id = chan_3_update.contents.short_channel_id;
        route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
        route.paths[1].hops[0].short_channel_id = chan_2_update.contents.short_channel_id;
        route.paths[1].hops[1].short_channel_id = chan_4_update.contents.short_channel_id;

        // Initiate the MPP payment.
        let payment_id = PaymentId(payment_hash.0);
        let mut route_params = RouteParameters {
                payment_params: route.payment_params.clone().unwrap(),
                final_value_msat: amt_msat,
        };

        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                payment_id, route_params.clone(), Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 2); // one monitor per path
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 2);

        // Pass half of the payment along the success path.
        let success_path_msgs = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
        pass_along_path(&nodes[0], &[&nodes[1], &nodes[3]], 2_000_000, payment_hash, Some(payment_secret), success_path_msgs, false, None);

        // Add the HTLC along the first hop.
        let fail_path_msgs_1 = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
        let (update_add, commitment_signed) = match fail_path_msgs_1 {
                MessageSendEvent::UpdateHTLCs { node_id: _, updates: msgs::CommitmentUpdate { ref update_add_htlcs, ref update_fulfill_htlcs, ref update_fail_htlcs, ref update_fail_malformed_htlcs, ref update_fee, ref commitment_signed } } => {
                        assert_eq!(update_add_htlcs.len(), 1);
                        assert!(update_fail_htlcs.is_empty());
                        assert!(update_fulfill_htlcs.is_empty());
                        assert!(update_fail_malformed_htlcs.is_empty());
                        assert!(update_fee.is_none());
                        (update_add_htlcs[0].clone(), commitment_signed.clone())
                },
                _ => panic!("Unexpected event"),
        };
        nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
        commitment_signed_dance!(nodes[2], nodes[0], commitment_signed, false);

        // Attempt to forward the payment and complete the 2nd path's failure.
        expect_pending_htlcs_forwardable!(&nodes[2]);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[2], vec![HTLCDestination::NextHopChannel { node_id: Some(nodes[3].node.get_our_node_id()), channel_id: chan_4_id }]);
        let htlc_updates = get_htlc_update_msgs!(nodes[2], nodes[0].node.get_our_node_id());
        assert!(htlc_updates.update_add_htlcs.is_empty());
        assert_eq!(htlc_updates.update_fail_htlcs.len(), 1);
        assert!(htlc_updates.update_fulfill_htlcs.is_empty());
        assert!(htlc_updates.update_fail_malformed_htlcs.is_empty());
        check_added_monitors!(nodes[2], 1);
        nodes[0].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &htlc_updates.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[0], nodes[2], htlc_updates.commitment_signed, false);
        let mut events = nodes[0].node.get_and_clear_pending_events();
        match events[1] {
                Event::PendingHTLCsForwardable { .. } => {},
                _ => panic!("Unexpected event")
        }
        events.remove(1);
        expect_payment_failed_conditions_event(events, payment_hash, false, PaymentFailedConditions::new().mpp_parts_remain());

        // Rebalance the channel so the second half of the payment can succeed.
        send_payment(&nodes[3], &vec!(&nodes[2])[..], 1_500_000);

        // Retry the second half of the payment and make sure it succeeds.
        route.paths.remove(0);
        route_params.final_value_msat = 1_000_000;
        route_params.payment_params.previously_failed_channels.push(chan_4_update.contents.short_channel_id);
        nodes[0].router.expect_find_route(route_params, Ok(route));
        nodes[0].node.process_pending_htlc_forwards();
        check_added_monitors!(nodes[0], 1);
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        pass_along_path(&nodes[0], &[&nodes[2], &nodes[3]], 2_000_000, payment_hash, Some(payment_secret), events.pop().unwrap(), true, None);
        claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_preimage);
}

fn do_mpp_receive_timeout(send_partial_mpp: bool) {
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        let (chan_1_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 0, 1);
        let (chan_2_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 0, 2);
        let (chan_3_update, _, chan_3_id, _) = create_announced_chan_between_nodes(&nodes, 1, 3);
        let (chan_4_update, _, _, _) = create_announced_chan_between_nodes(&nodes, 2, 3);

        let (mut route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[3], 100_000);
        let path = route.paths[0].clone();
        route.paths.push(path);
        route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
        route.paths[0].hops[0].short_channel_id = chan_1_update.contents.short_channel_id;
        route.paths[0].hops[1].short_channel_id = chan_3_update.contents.short_channel_id;
        route.paths[1].hops[0].pubkey = nodes[2].node.get_our_node_id();
        route.paths[1].hops[0].short_channel_id = chan_2_update.contents.short_channel_id;
        route.paths[1].hops[1].short_channel_id = chan_4_update.contents.short_channel_id;

        // Initiate the MPP payment.
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 2); // one monitor per path
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 2);

        // Pass half of the payment along the first path.
        let node_1_msgs = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
        pass_along_path(&nodes[0], &[&nodes[1], &nodes[3]], 200_000, payment_hash, Some(payment_secret), node_1_msgs, false, None);

        if send_partial_mpp {
                // Time out the partial MPP
                for _ in 0..MPP_TIMEOUT_TICKS {
                        nodes[3].node.timer_tick_occurred();
                }

                // Failed HTLC from node 3 -> 1
                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[3], vec![HTLCDestination::FailedPayment { payment_hash }]);
                let htlc_fail_updates_3_1 = get_htlc_update_msgs!(nodes[3], nodes[1].node.get_our_node_id());
                assert_eq!(htlc_fail_updates_3_1.update_fail_htlcs.len(), 1);
                nodes[1].node.handle_update_fail_htlc(&nodes[3].node.get_our_node_id(), &htlc_fail_updates_3_1.update_fail_htlcs[0]);
                check_added_monitors!(nodes[3], 1);
                commitment_signed_dance!(nodes[1], nodes[3], htlc_fail_updates_3_1.commitment_signed, false);

                // Failed HTLC from node 1 -> 0
                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::NextHopChannel { node_id: Some(nodes[3].node.get_our_node_id()), channel_id: chan_3_id }]);
                let htlc_fail_updates_1_0 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                assert_eq!(htlc_fail_updates_1_0.update_fail_htlcs.len(), 1);
                nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &htlc_fail_updates_1_0.update_fail_htlcs[0]);
                check_added_monitors!(nodes[1], 1);
                commitment_signed_dance!(nodes[0], nodes[1], htlc_fail_updates_1_0.commitment_signed, false);

                expect_payment_failed_conditions(&nodes[0], payment_hash, false, PaymentFailedConditions::new().mpp_parts_remain().expected_htlc_error_data(23, &[][..]));
        } else {
                // Pass half of the payment along the second path.
                let node_2_msgs = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
                pass_along_path(&nodes[0], &[&nodes[2], &nodes[3]], 200_000, payment_hash, Some(payment_secret), node_2_msgs, true, None);

                // Even after MPP_TIMEOUT_TICKS we should not timeout the MPP if we have all the parts
                for _ in 0..MPP_TIMEOUT_TICKS {
                        nodes[3].node.timer_tick_occurred();
                }

                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_preimage);
        }
}

#[test]
fn mpp_receive_timeout() {
        do_mpp_receive_timeout(true);
        do_mpp_receive_timeout(false);
}

#[test]
fn test_mpp_keysend() {
        let mut mpp_keysend_config = test_default_channel_config();
        mpp_keysend_config.accept_mpp_keysend = true;
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, Some(mpp_keysend_config)]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes(&nodes, 0, 2);
        create_announced_chan_between_nodes(&nodes, 1, 3);
        create_announced_chan_between_nodes(&nodes, 2, 3);
        let network_graph = nodes[0].network_graph.clone();

        let payer_pubkey = nodes[0].node.get_our_node_id();
        let payee_pubkey = nodes[3].node.get_our_node_id();
        let recv_value = 15_000_000;
        let route_params = RouteParameters {
                payment_params: PaymentParameters::for_keysend(payee_pubkey, 40, true),
                final_value_msat: recv_value,
        };
        let scorer = test_utils::TestScorer::new();
        let random_seed_bytes = chanmon_cfgs[0].keys_manager.get_secure_random_bytes();
        let route = find_route(&payer_pubkey, &route_params, &network_graph, None, nodes[0].logger,
                &scorer, &(), &random_seed_bytes).unwrap();

        let payment_preimage = PaymentPreimage([42; 32]);
        let payment_secret = PaymentSecret(payment_preimage.0);
        let payment_hash = nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage),
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_preimage.0)).unwrap();
        check_added_monitors!(nodes[0], 2);

        let expected_route: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 2);

        let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
        pass_along_path(&nodes[0], expected_route[0], recv_value, payment_hash.clone(),
                Some(payment_secret), ev.clone(), false, Some(payment_preimage));

        let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
        pass_along_path(&nodes[0], expected_route[1], recv_value, payment_hash.clone(),
                Some(payment_secret), ev.clone(), true, Some(payment_preimage));
        claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
}

#[test]
fn test_reject_mpp_keysend_htlc() {
        // This test enforces that we reject MPP keysend HTLCs if our config states we don't support
        // MPP keysend. When receiving a payment, if we don't support MPP keysend we'll reject the
        // payment if it's keysend and has a payment secret, never reaching our payment validation
        // logic. To check that we enforce rejecting MPP keysends in our payment logic, here we send
        // keysend payments without payment secrets, then modify them by adding payment secrets in the
        // final node in between receiving the HTLCs and actually processing them.
        let mut reject_mpp_keysend_cfg = test_default_channel_config();
        reject_mpp_keysend_cfg.accept_mpp_keysend = false;

        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, Some(reject_mpp_keysend_cfg)]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);
        let chan_1_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
        let chan_2_id = create_announced_chan_between_nodes(&nodes, 0, 2).0.contents.short_channel_id;
        let chan_3_id = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents.short_channel_id;
        let (update_a, _, chan_4_channel_id, _) = create_announced_chan_between_nodes(&nodes, 2, 3);
        let chan_4_id = update_a.contents.short_channel_id;
        let amount = 40_000;
        let (mut route, payment_hash, payment_preimage, _) = get_route_and_payment_hash!(nodes[0], nodes[3], amount);

        // Pay along nodes[1]
        route.paths[0].hops[0].pubkey = nodes[1].node.get_our_node_id();
        route.paths[0].hops[0].short_channel_id = chan_1_id;
        route.paths[0].hops[1].short_channel_id = chan_3_id;

        let payment_id_0 = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes());
        nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage), RecipientOnionFields::spontaneous_empty(), payment_id_0).unwrap();
        check_added_monitors!(nodes[0], 1);

        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let update_add_0 = update_0.update_add_htlcs[0].clone();
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add_0);
        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);
        expect_pending_htlcs_forwardable!(nodes[1]);

        check_added_monitors!(&nodes[1], 1);
        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[3].node.get_our_node_id());
        let update_add_1 = update_1.update_add_htlcs[0].clone();
        nodes[3].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &update_add_1);
        commitment_signed_dance!(nodes[3], nodes[1], update_1.commitment_signed, false, true);

        assert!(nodes[3].node.get_and_clear_pending_msg_events().is_empty());
        for (_, pending_forwards) in nodes[3].node.forward_htlcs.lock().unwrap().iter_mut() {
                for f in pending_forwards.iter_mut() {
                        match f {
                                &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo { ref mut forward_info, .. }) => {
                                        match forward_info.routing {
                                                PendingHTLCRouting::ReceiveKeysend { ref mut payment_data, .. } => {
                                                        *payment_data = Some(msgs::FinalOnionHopData {
                                                                payment_secret: PaymentSecret([42; 32]),
                                                                total_msat: amount * 2,
                                                        });
                                                },
                                                _ => panic!("Expected PendingHTLCRouting::ReceiveKeysend"),
                                        }
                                },
                                _ => {},
                        }
                }
        }
        expect_pending_htlcs_forwardable!(nodes[3]);

        // Pay along nodes[2]
        route.paths[0].hops[0].pubkey = nodes[2].node.get_our_node_id();
        route.paths[0].hops[0].short_channel_id = chan_2_id;
        route.paths[0].hops[1].short_channel_id = chan_4_id;

        let payment_id_1 = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes());
        nodes[0].node.send_spontaneous_payment(&route, Some(payment_preimage), RecipientOnionFields::spontaneous_empty(), payment_id_1).unwrap();
        check_added_monitors!(nodes[0], 1);

        let update_2 = get_htlc_update_msgs!(nodes[0], nodes[2].node.get_our_node_id());
        let update_add_2 = update_2.update_add_htlcs[0].clone();
        nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add_2);
        commitment_signed_dance!(nodes[2], nodes[0], &update_2.commitment_signed, false, true);
        expect_pending_htlcs_forwardable!(nodes[2]);

        check_added_monitors!(&nodes[2], 1);
        let update_3 = get_htlc_update_msgs!(nodes[2], nodes[3].node.get_our_node_id());
        let update_add_3 = update_3.update_add_htlcs[0].clone();
        nodes[3].node.handle_update_add_htlc(&nodes[2].node.get_our_node_id(), &update_add_3);
        commitment_signed_dance!(nodes[3], nodes[2], update_3.commitment_signed, false, true);

        assert!(nodes[3].node.get_and_clear_pending_msg_events().is_empty());
        for (_, pending_forwards) in nodes[3].node.forward_htlcs.lock().unwrap().iter_mut() {
                for f in pending_forwards.iter_mut() {
                        match f {
                                &mut HTLCForwardInfo::AddHTLC(PendingAddHTLCInfo { ref mut forward_info, .. }) => {
                                        match forward_info.routing {
                                                PendingHTLCRouting::ReceiveKeysend { ref mut payment_data, .. } => {
                                                        *payment_data = Some(msgs::FinalOnionHopData {
                                                                payment_secret: PaymentSecret([42; 32]),
                                                                total_msat: amount * 2,
                                                        });
                                                },
                                                _ => panic!("Expected PendingHTLCRouting::ReceiveKeysend"),
                                        }
                                },
                                _ => {},
                        }
                }
        }
        expect_pending_htlcs_forwardable!(nodes[3]);
        check_added_monitors!(nodes[3], 1);

        // Fail back along nodes[2]
        let update_fail_0 = get_htlc_update_msgs!(&nodes[3], &nodes[2].node.get_our_node_id());
        nodes[2].node.handle_update_fail_htlc(&nodes[3].node.get_our_node_id(), &update_fail_0.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[2], nodes[3], update_fail_0.commitment_signed, false);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[2], vec![HTLCDestination::NextHopChannel { node_id: Some(nodes[3].node.get_our_node_id()), channel_id: chan_4_channel_id }]);
        check_added_monitors!(nodes[2], 1);

        let update_fail_1 = get_htlc_update_msgs!(nodes[2], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &update_fail_1.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[0], nodes[2], update_fail_1.commitment_signed, false);

        expect_payment_failed_conditions(&nodes[0], payment_hash, true, PaymentFailedConditions::new());
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[3], vec![HTLCDestination::FailedPayment { payment_hash }]);
}


#[test]
fn no_pending_leak_on_initial_send_failure() {
        // In an earlier version of our payment tracking, we'd have a retry entry even when the initial
        // HTLC for payment failed to send due to local channel errors (e.g. peer disconnected). In this
        // case, the user wouldn't have a PaymentId to retry the payment with, but we'd think we have a
        // pending payment forever and never time it out.
        // Here we test exactly that - retrying a payment when a peer was disconnected on the first
        // try, and then check that no pending payment is being tracked.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);

        let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);

        nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());

        unwrap_send_err!(nodes[0].node.send_payment_with_route(&route, payment_hash,
                        RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
                ), true, APIError::ChannelUnavailable { ref err },
                assert_eq!(err, "Peer for first hop currently disconnected"));

        assert!(!nodes[0].node.has_pending_payments());
}

fn do_retry_with_no_persist(confirm_before_reload: bool) {
        // If we send a pending payment and `send_payment` returns success, we should always either
        // return a payment failure event or a payment success event, and on failure the payment should
        // be retryable.
        //
        // In order to do so when the ChannelManager isn't immediately persisted (which is normal - its
        // always persisted asynchronously), the ChannelManager has to reload some payment data from
        // ChannelMonitor(s) in some cases. This tests that reloading.
        //
        // `confirm_before_reload` confirms the channel-closing commitment transaction on-chain prior
        // to reloading the ChannelManager, increasing test coverage in ChannelMonitor HTLC tracking
        // which has separate codepaths for "commitment transaction already confirmed" and not.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let persister: test_utils::TestPersister;
        let new_chain_monitor: test_utils::TestChainMonitor;
        let nodes_0_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;
        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let chan_id = create_announced_chan_between_nodes(&nodes, 0, 1).2;
        let (_, _, chan_id_2, _) = create_announced_chan_between_nodes(&nodes, 1, 2);

        // Serialize the ChannelManager prior to sending payments
        let nodes_0_serialized = nodes[0].node.encode();

        // Send two payments - one which will get to nodes[2] and will be claimed, one which we'll time
        // out and retry.
        let amt_msat = 1_000_000;
        let (route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], amt_msat);
        let (payment_preimage_1, payment_hash_1, _, payment_id_1) = send_along_route(&nodes[0], route.clone(), &[&nodes[1], &nodes[2]], 1_000_000);
        let route_params = RouteParameters {
                payment_params: route.payment_params.clone().unwrap(),
                final_value_msat: amt_msat,
        };
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 1);

        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        let payment_event = SendEvent::from_event(events.pop().unwrap());
        assert_eq!(payment_event.node_id, nodes[1].node.get_our_node_id());

        // We relay the payment to nodes[1] while its disconnected from nodes[2], causing the payment
        // to be returned immediately to nodes[0], without having nodes[2] fail the inbound payment
        // which would prevent retry.
        nodes[1].node.peer_disconnected(&nodes[2].node.get_our_node_id());
        nodes[2].node.peer_disconnected(&nodes[1].node.get_our_node_id());

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false, true);
        // nodes[1] now immediately fails the HTLC as the next-hop channel is disconnected
        let _ = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        reconnect_nodes(ReconnectArgs::new(&nodes[1], &nodes[2]));

        let as_commitment_tx = get_local_commitment_txn!(nodes[0], chan_id)[0].clone();
        if confirm_before_reload {
                mine_transaction(&nodes[0], &as_commitment_tx);
                nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().clear();
        }

        // The ChannelMonitor should always be the latest version, as we're required to persist it
        // during the `commitment_signed_dance!()`.
        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        reload_node!(nodes[0], test_default_channel_config(), &nodes_0_serialized, &[&chan_0_monitor_serialized], persister, new_chain_monitor, nodes_0_deserialized);

        // On reload, the ChannelManager should realize it is stale compared to the ChannelMonitor and
        // force-close the channel.
        check_closed_event!(nodes[0], 1, ClosureReason::OutdatedChannelManager);
        assert!(nodes[0].node.list_channels().is_empty());
        assert!(nodes[0].node.has_pending_payments());
        nodes[0].node.timer_tick_occurred();
        if !confirm_before_reload {
                let as_broadcasted_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                assert_eq!(as_broadcasted_txn.len(), 1);
                assert_eq!(as_broadcasted_txn[0].txid(), as_commitment_tx.txid());
        } else {
                assert!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty());
        }
        check_added_monitors!(nodes[0], 1);

        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());
        nodes[0].node.peer_connected(&nodes[1].node.get_our_node_id(), &msgs::Init {
                features: nodes[1].node.init_features(), networks: None, remote_network_address: None
        }, true).unwrap();
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());

        // Now nodes[1] should send a channel reestablish, which nodes[0] will respond to with an
        // error, as the channel has hit the chain.
        nodes[1].node.peer_connected(&nodes[0].node.get_our_node_id(), &msgs::Init {
                features: nodes[0].node.init_features(), networks: None, remote_network_address: None
        }, false).unwrap();
        let bs_reestablish = get_chan_reestablish_msgs!(nodes[1], nodes[0]).pop().unwrap();
        nodes[0].node.handle_channel_reestablish(&nodes[1].node.get_our_node_id(), &bs_reestablish);
        let as_err = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(as_err.len(), 1);
        match as_err[0] {
                MessageSendEvent::HandleError { node_id, action: msgs::ErrorAction::SendErrorMessage { ref msg } } => {
                        assert_eq!(node_id, nodes[1].node.get_our_node_id());
                        nodes[1].node.handle_error(&nodes[0].node.get_our_node_id(), msg);
                        check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id())) });
                        check_added_monitors!(nodes[1], 1);
                        assert_eq!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1);
                },
                _ => panic!("Unexpected event"),
        }
        check_closed_broadcast!(nodes[1], false);

        // Now claim the first payment, which should allow nodes[1] to claim the payment on-chain when
        // we close in a moment.
        nodes[2].node.claim_funds(payment_preimage_1);
        check_added_monitors!(nodes[2], 1);
        expect_payment_claimed!(nodes[2], payment_hash_1, 1_000_000);

        let htlc_fulfill_updates = get_htlc_update_msgs!(nodes[2], nodes[1].node.get_our_node_id());
        nodes[1].node.handle_update_fulfill_htlc(&nodes[2].node.get_our_node_id(), &htlc_fulfill_updates.update_fulfill_htlcs[0]);
        check_added_monitors!(nodes[1], 1);
        commitment_signed_dance!(nodes[1], nodes[2], htlc_fulfill_updates.commitment_signed, false);
        expect_payment_forwarded!(nodes[1], nodes[0], nodes[2], None, false, false);

        if confirm_before_reload {
                let best_block = nodes[0].blocks.lock().unwrap().last().unwrap().clone();
                nodes[0].node.best_block_updated(&best_block.0.header, best_block.1);
        }

        // Create a new channel on which to retry the payment before we fail the payment via the
        // HTLC-Timeout transaction. This avoids ChannelManager timing out the payment due to us
        // connecting several blocks while creating the channel (implying time has passed).
        create_announced_chan_between_nodes(&nodes, 0, 1);
        assert_eq!(nodes[0].node.list_usable_channels().len(), 1);

        mine_transaction(&nodes[1], &as_commitment_tx);
        let bs_htlc_claim_txn = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(bs_htlc_claim_txn.len(), 1);
        check_spends!(bs_htlc_claim_txn[0], as_commitment_tx);

        if !confirm_before_reload {
                mine_transaction(&nodes[0], &as_commitment_tx);
        }
        mine_transaction(&nodes[0], &bs_htlc_claim_txn[0]);
        expect_payment_sent!(nodes[0], payment_preimage_1);
        connect_blocks(&nodes[0], TEST_FINAL_CLTV*4 + 20);
        let (first_htlc_timeout_tx, second_htlc_timeout_tx) = {
                let mut txn = nodes[0].tx_broadcaster.unique_txn_broadcast();
                assert_eq!(txn.len(), 2);
                (txn.remove(0), txn.remove(0))
        };
        check_spends!(first_htlc_timeout_tx, as_commitment_tx);
        check_spends!(second_htlc_timeout_tx, as_commitment_tx);
        if first_htlc_timeout_tx.input[0].previous_output == bs_htlc_claim_txn[0].input[0].previous_output {
                confirm_transaction(&nodes[0], &second_htlc_timeout_tx);
        } else {
                confirm_transaction(&nodes[0], &first_htlc_timeout_tx);
        }
        nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().clear();
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, PaymentFailedConditions::new());

        // Finally, retry the payment (which was reloaded from the ChannelMonitor when nodes[0] was
        // reloaded) via a route over the new channel, which work without issue and eventually be
        // received and claimed at the recipient just like any other payment.
        let (mut new_route, _, _, _) = get_route_and_payment_hash!(nodes[0], nodes[2], 1_000_000);

        // Update the fee on the middle hop to ensure PaymentSent events have the correct (retried) fee
        // and not the original fee. We also update node[1]'s relevant config as
        // do_claim_payment_along_route expects us to never overpay.
        {
                let per_peer_state = nodes[1].node.per_peer_state.read().unwrap();
                let mut peer_state = per_peer_state.get(&nodes[2].node.get_our_node_id())
                        .unwrap().lock().unwrap();
                let mut channel = peer_state.channel_by_id.get_mut(&chan_id_2).unwrap();
                let mut new_config = channel.context.config();
                new_config.forwarding_fee_base_msat += 100_000;
                channel.context.update_config(&new_config);
                new_route.paths[0].hops[0].fee_msat += 100_000;
        }

        // Force expiration of the channel's previous config.
        for _ in 0..EXPIRE_PREV_CONFIG_TICKS {
                nodes[1].node.timer_tick_occurred();
        }

        assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash, // Shouldn't be allowed to retry a fulfilled payment
                RecipientOnionFields::secret_only(payment_secret), payment_id_1).is_err());
        nodes[0].node.send_payment_with_route(&new_route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        pass_along_path(&nodes[0], &[&nodes[1], &nodes[2]], 1_000_000, payment_hash, Some(payment_secret), events.pop().unwrap(), true, None);
        do_claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
        expect_payment_sent!(nodes[0], payment_preimage, Some(new_route.paths[0].hops[0].fee_msat));
}

#[test]
fn retry_with_no_persist() {
        do_retry_with_no_persist(true);
        do_retry_with_no_persist(false);
}

fn do_test_completed_payment_not_retryable_on_reload(use_dust: bool) {
        // Test that an off-chain completed payment is not retryable on restart. This was previously
        // broken for dust payments, but we test for both dust and non-dust payments.
        //
        // `use_dust` switches to using a dust HTLC, which results in the HTLC not having an on-chain
        // output at all.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);

        let mut manually_accept_config = test_default_channel_config();
        manually_accept_config.manually_accept_inbound_channels = true;

        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, Some(manually_accept_config), None]);

        let first_persister: test_utils::TestPersister;
        let first_new_chain_monitor: test_utils::TestChainMonitor;
        let first_nodes_0_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;
        let second_persister: test_utils::TestPersister;
        let second_new_chain_monitor: test_utils::TestChainMonitor;
        let second_nodes_0_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;
        let third_persister: test_utils::TestPersister;
        let third_new_chain_monitor: test_utils::TestChainMonitor;
        let third_nodes_0_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;

        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        // Because we set nodes[1] to manually accept channels, just open a 0-conf channel.
        let (funding_tx, chan_id) = open_zero_conf_channel(&nodes[0], &nodes[1], None);
        confirm_transaction(&nodes[0], &funding_tx);
        confirm_transaction(&nodes[1], &funding_tx);
        // Ignore the announcement_signatures messages
        nodes[0].node.get_and_clear_pending_msg_events();
        nodes[1].node.get_and_clear_pending_msg_events();
        let chan_id_2 = create_announced_chan_between_nodes(&nodes, 1, 2).2;

        // Serialize the ChannelManager prior to sending payments
        let mut nodes_0_serialized = nodes[0].node.encode();

        let route = get_route_and_payment_hash!(nodes[0], nodes[2], if use_dust { 1_000 } else { 1_000_000 }).0;
        let (payment_preimage, payment_hash, payment_secret, payment_id) = send_along_route(&nodes[0], route, &[&nodes[1], &nodes[2]], if use_dust { 1_000 } else { 1_000_000 });

        // The ChannelMonitor should always be the latest version, as we're required to persist it
        // during the `commitment_signed_dance!()`.
        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();

        reload_node!(nodes[0], test_default_channel_config(), nodes_0_serialized, &[&chan_0_monitor_serialized], first_persister, first_new_chain_monitor, first_nodes_0_deserialized);
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());

        // On reload, the ChannelManager should realize it is stale compared to the ChannelMonitor and
        // force-close the channel.
        check_closed_event!(nodes[0], 1, ClosureReason::OutdatedChannelManager);
        nodes[0].node.timer_tick_occurred();
        assert!(nodes[0].node.list_channels().is_empty());
        assert!(nodes[0].node.has_pending_payments());
        assert_eq!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.peer_connected(&nodes[1].node.get_our_node_id(), &msgs::Init {
                features: nodes[1].node.init_features(), networks: None, remote_network_address: None
        }, true).unwrap();
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());

        // Now nodes[1] should send a channel reestablish, which nodes[0] will respond to with an
        // error, as the channel has hit the chain.
        nodes[1].node.peer_connected(&nodes[0].node.get_our_node_id(), &msgs::Init {
                features: nodes[0].node.init_features(), networks: None, remote_network_address: None
        }, false).unwrap();
        let bs_reestablish = get_chan_reestablish_msgs!(nodes[1], nodes[0]).pop().unwrap();
        nodes[0].node.handle_channel_reestablish(&nodes[1].node.get_our_node_id(), &bs_reestablish);
        let as_err = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(as_err.len(), 1);
        let bs_commitment_tx;
        match as_err[0] {
                MessageSendEvent::HandleError { node_id, action: msgs::ErrorAction::SendErrorMessage { ref msg } } => {
                        assert_eq!(node_id, nodes[1].node.get_our_node_id());
                        nodes[1].node.handle_error(&nodes[0].node.get_our_node_id(), msg);
                        check_closed_event!(nodes[1], 1, ClosureReason::CounterpartyForceClosed { peer_msg: UntrustedString(format!("Got a message for a channel from the wrong node! No such channel for the passed counterparty_node_id {}", &nodes[1].node.get_our_node_id())) });
                        check_added_monitors!(nodes[1], 1);
                        bs_commitment_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                },
                _ => panic!("Unexpected event"),
        }
        check_closed_broadcast!(nodes[1], false);

        // Now fail back the payment from nodes[2] to nodes[1]. This doesn't really matter as the
        // previous hop channel is already on-chain, but it makes nodes[2] willing to see additional
        // incoming HTLCs with the same payment hash later.
        nodes[2].node.fail_htlc_backwards(&payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[2], [HTLCDestination::FailedPayment { payment_hash }]);
        check_added_monitors!(nodes[2], 1);

        let htlc_fulfill_updates = get_htlc_update_msgs!(nodes[2], nodes[1].node.get_our_node_id());
        nodes[1].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &htlc_fulfill_updates.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[1], nodes[2], htlc_fulfill_updates.commitment_signed, false);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1],
                [HTLCDestination::NextHopChannel { node_id: Some(nodes[2].node.get_our_node_id()), channel_id: chan_id_2 }]);

        // Connect the HTLC-Timeout transaction, timing out the HTLC on both nodes (but not confirming
        // the HTLC-Timeout transaction beyond 1 conf). For dust HTLCs, the HTLC is considered resolved
        // after the commitment transaction, so always connect the commitment transaction.
        mine_transaction(&nodes[0], &bs_commitment_tx[0]);
        mine_transaction(&nodes[1], &bs_commitment_tx[0]);
        if !use_dust {
                connect_blocks(&nodes[0], TEST_FINAL_CLTV + (MIN_CLTV_EXPIRY_DELTA as u32));
                connect_blocks(&nodes[1], TEST_FINAL_CLTV + (MIN_CLTV_EXPIRY_DELTA as u32));
                let as_htlc_timeout = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                check_spends!(as_htlc_timeout[0], bs_commitment_tx[0]);
                assert_eq!(as_htlc_timeout.len(), 1);

                mine_transaction(&nodes[0], &as_htlc_timeout[0]);
                // nodes[0] may rebroadcast (or RBF-bump) its HTLC-Timeout, so wipe the announced set.
                nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().clear();
                mine_transaction(&nodes[1], &as_htlc_timeout[0]);
        }

        // Create a new channel on which to retry the payment before we fail the payment via the
        // HTLC-Timeout transaction. This avoids ChannelManager timing out the payment due to us
        // connecting several blocks while creating the channel (implying time has passed).
        // We do this with a zero-conf channel to avoid connecting blocks as a side-effect.
        let (_, chan_id_3) = open_zero_conf_channel(&nodes[0], &nodes[1], None);
        assert_eq!(nodes[0].node.list_usable_channels().len(), 1);

        // If we attempt to retry prior to the HTLC-Timeout (or commitment transaction, for dust HTLCs)
        // confirming, we will fail as it's considered still-pending...
        let (new_route, _, _, _) = get_route_and_payment_hash!(nodes[0], nodes[2], if use_dust { 1_000 } else { 1_000_000 });
        match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());

        // After ANTI_REORG_DELAY confirmations, the HTLC should be failed and we can try the payment
        // again. We serialize the node first as we'll then test retrying the HTLC after a restart
        // (which should also still work).
        connect_blocks(&nodes[0], ANTI_REORG_DELAY - 1);
        connect_blocks(&nodes[1], ANTI_REORG_DELAY - 1);
        expect_payment_failed_conditions(&nodes[0], payment_hash, false, PaymentFailedConditions::new());

        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        let chan_1_monitor_serialized = get_monitor!(nodes[0], chan_id_3).encode();
        nodes_0_serialized = nodes[0].node.encode();

        // After the payment failed, we're free to send it again.
        assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), payment_id).is_ok());
        assert!(!nodes[0].node.get_and_clear_pending_msg_events().is_empty());

        reload_node!(nodes[0], test_default_channel_config(), nodes_0_serialized, &[&chan_0_monitor_serialized, &chan_1_monitor_serialized], second_persister, second_new_chain_monitor, second_nodes_0_deserialized);
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());

        nodes[0].node.test_process_background_events();
        check_added_monitors(&nodes[0], 1);

        let mut reconnect_args = ReconnectArgs::new(&nodes[0], &nodes[1]);
        reconnect_args.send_channel_ready = (true, true);
        reconnect_nodes(reconnect_args);

        // Now resend the payment, delivering the HTLC and actually claiming it this time. This ensures
        // the payment is not (spuriously) listed as still pending.
        assert!(nodes[0].node.send_payment_with_route(&new_route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), payment_id).is_ok());
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], if use_dust { 1_000 } else { 1_000_000 }, payment_hash, payment_secret);
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);

        match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());

        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        let chan_1_monitor_serialized = get_monitor!(nodes[0], chan_id_3).encode();
        nodes_0_serialized = nodes[0].node.encode();

        // Check that after reload we can send the payment again (though we shouldn't, since it was
        // claimed previously).
        reload_node!(nodes[0], test_default_channel_config(), nodes_0_serialized, &[&chan_0_monitor_serialized, &chan_1_monitor_serialized], third_persister, third_new_chain_monitor, third_nodes_0_deserialized);
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());

        nodes[0].node.test_process_background_events();
        check_added_monitors(&nodes[0], 1);

        reconnect_nodes(ReconnectArgs::new(&nodes[0], &nodes[1]));

        match nodes[0].node.send_payment_with_route(&new_route, payment_hash, RecipientOnionFields::secret_only(payment_secret), payment_id) {
                Err(PaymentSendFailure::DuplicatePayment) => {},
                _ => panic!("Unexpected error")
        }
        assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());
}

#[test]
fn test_completed_payment_not_retryable_on_reload() {
        do_test_completed_payment_not_retryable_on_reload(true);
        do_test_completed_payment_not_retryable_on_reload(false);
}


fn do_test_dup_htlc_onchain_fails_on_reload(persist_manager_post_event: bool, confirm_commitment_tx: bool, payment_timeout: bool) {
        // When a Channel is closed, any outbound HTLCs which were relayed through it are simply
        // dropped when the Channel is. From there, the ChannelManager relies on the ChannelMonitor
        // having a copy of the relevant fail-/claim-back data and processes the HTLC fail/claim when
        // the ChannelMonitor tells it to.
        //
        // If, due to an on-chain event, an HTLC is failed/claimed, we should avoid providing the
        // ChannelManager the HTLC event until after the monitor is re-persisted. This should prevent a
        // duplicate HTLC fail/claim (e.g. via a PaymentPathFailed event).
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let persister: test_utils::TestPersister;
        let new_chain_monitor: test_utils::TestChainMonitor;
        let nodes_0_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let (_, _, chan_id, funding_tx) = create_announced_chan_between_nodes(&nodes, 0, 1);

        // Route a payment, but force-close the channel before the HTLC fulfill message arrives at
        // nodes[0].
        let (payment_preimage, payment_hash, _) = route_payment(&nodes[0], &[&nodes[1]], 10_000_000);
        nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id()).unwrap();
        check_closed_broadcast!(nodes[0], true);
        check_added_monitors!(nodes[0], 1);
        check_closed_event!(nodes[0], 1, ClosureReason::HolderForceClosed);

        nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
        nodes[1].node.peer_disconnected(&nodes[0].node.get_our_node_id());

        // Connect blocks until the CLTV timeout is up so that we get an HTLC-Timeout transaction
        connect_blocks(&nodes[0], TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1);
        let node_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(node_txn.len(), 3);
        assert_eq!(node_txn[0].txid(), node_txn[1].txid());
        check_spends!(node_txn[1], funding_tx);
        check_spends!(node_txn[2], node_txn[1]);
        let timeout_txn = vec![node_txn[2].clone()];

        nodes[1].node.claim_funds(payment_preimage);
        check_added_monitors!(nodes[1], 1);
        expect_payment_claimed!(nodes[1], payment_hash, 10_000_000);

        connect_block(&nodes[1], &create_dummy_block(nodes[1].best_block_hash(), 42, vec![node_txn[1].clone()]));
        check_closed_broadcast!(nodes[1], true);
        check_added_monitors!(nodes[1], 1);
        check_closed_event!(nodes[1], 1, ClosureReason::CommitmentTxConfirmed);
        let claim_txn = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(claim_txn.len(), 1);
        check_spends!(claim_txn[0], node_txn[1]);

        connect_block(&nodes[0], &create_dummy_block(nodes[0].best_block_hash(), 42, vec![node_txn[1].clone()]));

        if confirm_commitment_tx {
                connect_blocks(&nodes[0], BREAKDOWN_TIMEOUT as u32 - 1);
        }

        let claim_block = create_dummy_block(nodes[0].best_block_hash(), 42, if payment_timeout { timeout_txn } else { vec![claim_txn[0].clone()] });

        if payment_timeout {
                assert!(confirm_commitment_tx); // Otherwise we're spending below our CSV!
                connect_block(&nodes[0], &claim_block);
                connect_blocks(&nodes[0], ANTI_REORG_DELAY - 2);
        }

        // Now connect the HTLC claim transaction with the ChainMonitor-generated ChannelMonitor update
        // returning InProgress. This should cause the claim event to never make its way to the
        // ChannelManager.
        chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clear();
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);

        if payment_timeout {
                connect_blocks(&nodes[0], 1);
        } else {
                connect_block(&nodes[0], &claim_block);
        }

        let funding_txo = OutPoint { txid: funding_tx.txid(), index: 0 };
        let mon_updates: Vec<_> = chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap()
                .get_mut(&funding_txo).unwrap().drain().collect();
        // If we are using chain::Confirm instead of chain::Listen, we will get the same update twice.
        // If we're testing connection idempotency we may get substantially more.
        assert!(mon_updates.len() >= 1);
        assert!(nodes[0].chain_monitor.release_pending_monitor_events().is_empty());
        assert!(nodes[0].node.get_and_clear_pending_events().is_empty());

        // If we persist the ChannelManager here, we should get the PaymentSent event after
        // deserialization.
        let mut chan_manager_serialized = Vec::new();
        if !persist_manager_post_event {
                chan_manager_serialized = nodes[0].node.encode();
        }

        // Now persist the ChannelMonitor and inform the ChainMonitor that we're done, generating the
        // payment sent event.
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        for update in mon_updates {
                nodes[0].chain_monitor.chain_monitor.channel_monitor_updated(funding_txo, update).unwrap();
        }
        if payment_timeout {
                expect_payment_failed!(nodes[0], payment_hash, false);
        } else {
                expect_payment_sent!(nodes[0], payment_preimage);
        }

        // If we persist the ChannelManager after we get the PaymentSent event, we shouldn't get it
        // twice.
        if persist_manager_post_event {
                chan_manager_serialized = nodes[0].node.encode();
        }

        // Now reload nodes[0]...
        reload_node!(nodes[0], &chan_manager_serialized, &[&chan_0_monitor_serialized], persister, new_chain_monitor, nodes_0_deserialized);

        if persist_manager_post_event {
                assert!(nodes[0].node.get_and_clear_pending_events().is_empty());
        } else if payment_timeout {
                expect_payment_failed!(nodes[0], payment_hash, false);
        } else {
                expect_payment_sent!(nodes[0], payment_preimage);
        }

        // Note that if we re-connect the block which exposed nodes[0] to the payment preimage (but
        // which the current ChannelMonitor has not seen), the ChannelManager's de-duplication of
        // payment events should kick in, leaving us with no pending events here.
        let height = nodes[0].blocks.lock().unwrap().len() as u32 - 1;
        nodes[0].chain_monitor.chain_monitor.block_connected(&claim_block, height);
        assert!(nodes[0].node.get_and_clear_pending_events().is_empty());
        check_added_monitors(&nodes[0], 1);
}

#[test]
fn test_dup_htlc_onchain_fails_on_reload() {
        do_test_dup_htlc_onchain_fails_on_reload(true, true, true);
        do_test_dup_htlc_onchain_fails_on_reload(true, true, false);
        do_test_dup_htlc_onchain_fails_on_reload(true, false, false);
        do_test_dup_htlc_onchain_fails_on_reload(false, true, true);
        do_test_dup_htlc_onchain_fails_on_reload(false, true, false);
        do_test_dup_htlc_onchain_fails_on_reload(false, false, false);
}

#[test]
fn test_fulfill_restart_failure() {
        // When we receive an update_fulfill_htlc message, we immediately consider the HTLC fully
        // fulfilled. At this point, the peer can reconnect and decide to either fulfill the HTLC
        // again, or fail it, giving us free money.
        //
        // Of course probably they won't fail it and give us free money, but because we have code to
        // handle it, we should test the logic for it anyway. We do that here.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let persister: test_utils::TestPersister;
        let new_chain_monitor: test_utils::TestChainMonitor;
        let nodes_1_deserialized: ChannelManager<&test_utils::TestChainMonitor, &test_utils::TestBroadcaster, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestKeysInterface, &test_utils::TestFeeEstimator, &test_utils::TestRouter, &test_utils::TestLogger>;
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let chan_id = create_announced_chan_between_nodes(&nodes, 0, 1).2;
        let (payment_preimage, payment_hash, _) = route_payment(&nodes[0], &[&nodes[1]], 100_000);

        // The simplest way to get a failure after a fulfill is to reload nodes[1] from a state
        // pre-fulfill, which we do by serializing it here.
        let chan_manager_serialized = nodes[1].node.encode();
        let chan_0_monitor_serialized = get_monitor!(nodes[1], chan_id).encode();

        nodes[1].node.claim_funds(payment_preimage);
        check_added_monitors!(nodes[1], 1);
        expect_payment_claimed!(nodes[1], payment_hash, 100_000);

        let htlc_fulfill_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &htlc_fulfill_updates.update_fulfill_htlcs[0]);
        expect_payment_sent_without_paths!(nodes[0], payment_preimage);

        // Now reload nodes[1]...
        reload_node!(nodes[1], &chan_manager_serialized, &[&chan_0_monitor_serialized], persister, new_chain_monitor, nodes_1_deserialized);

        nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id());
        reconnect_nodes(ReconnectArgs::new(&nodes[0], &nodes[1]));

        nodes[1].node.fail_htlc_backwards(&payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
        check_added_monitors!(nodes[1], 1);
        let htlc_fail_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &htlc_fail_updates.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[0], nodes[1], htlc_fail_updates.commitment_signed, false);
        // nodes[0] shouldn't generate any events here, while it just got a payment failure completion
        // it had already considered the payment fulfilled, and now they just got free money.
        assert!(nodes[0].node.get_and_clear_pending_events().is_empty());
}

#[test]
fn get_ldk_payment_preimage() {
        // Ensure that `ChannelManager::get_payment_preimage` can successfully be used to claim a payment.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);
        create_announced_chan_between_nodes(&nodes, 0, 1);

        let amt_msat = 60_000;
        let expiry_secs = 60 * 60;
        let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment(Some(amt_msat), expiry_secs, None).unwrap();

        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_bolt11_features(nodes[1].node.invoice_features()).unwrap();
        let scorer = test_utils::TestScorer::new();
        let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
        let random_seed_bytes = keys_manager.get_secure_random_bytes();
        let route = get_route(
                &nodes[0].node.get_our_node_id(), &payment_params, &nodes[0].network_graph.read_only(),
                Some(&nodes[0].node.list_usable_channels().iter().collect::<Vec<_>>()),
                amt_msat, nodes[0].logger, &scorer, &(), &random_seed_bytes).unwrap();
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        check_added_monitors!(nodes[0], 1);

        // Make sure to use `get_payment_preimage`
        let payment_preimage = nodes[1].node.get_payment_preimage(payment_hash, payment_secret).unwrap();
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        pass_along_path(&nodes[0], &[&nodes[1]], amt_msat, payment_hash, Some(payment_secret), events.pop().unwrap(), true, Some(payment_preimage));
        claim_payment_along_route(&nodes[0], &[&[&nodes[1]]], false, payment_preimage);
}

#[test]
fn sent_probe_is_probe_of_sending_node() {
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes(&nodes, 1, 2);

        // First check we refuse to build a single-hop probe
        let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[1], 100_000);
        assert!(nodes[0].node.send_probe(route.paths[0].clone()).is_err());

        // Then build an actual two-hop probing path
        let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], 100_000);

        match nodes[0].node.send_probe(route.paths[0].clone()) {
                Ok((payment_hash, payment_id)) => {
                        assert!(nodes[0].node.payment_is_probe(&payment_hash, &payment_id));
                        assert!(!nodes[1].node.payment_is_probe(&payment_hash, &payment_id));
                        assert!(!nodes[2].node.payment_is_probe(&payment_hash, &payment_id));
                },
                _ => panic!(),
        }

        get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        check_added_monitors!(nodes[0], 1);
}

#[test]
fn successful_probe_yields_event() {
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes(&nodes, 1, 2);

        let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], 100_000);

        let (payment_hash, payment_id) = nodes[0].node.send_probe(route.paths[0].clone()).unwrap();

        // node[0] -- update_add_htlcs -> node[1]
        check_added_monitors!(nodes[0], 1);
        let updates = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let probe_event = SendEvent::from_commitment_update(nodes[1].node.get_our_node_id(), updates);
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &probe_event.msgs[0]);
        check_added_monitors!(nodes[1], 0);
        commitment_signed_dance!(nodes[1], nodes[0], probe_event.commitment_msg, false);
        expect_pending_htlcs_forwardable!(nodes[1]);

        // node[1] -- update_add_htlcs -> node[2]
        check_added_monitors!(nodes[1], 1);
        let updates = get_htlc_update_msgs!(nodes[1], nodes[2].node.get_our_node_id());
        let probe_event = SendEvent::from_commitment_update(nodes[1].node.get_our_node_id(), updates);
        nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &probe_event.msgs[0]);
        check_added_monitors!(nodes[2], 0);
        commitment_signed_dance!(nodes[2], nodes[1], probe_event.commitment_msg, true, true);

        // node[1] <- update_fail_htlcs -- node[2]
        let updates = get_htlc_update_msgs!(nodes[2], nodes[1].node.get_our_node_id());
        nodes[1].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
        check_added_monitors!(nodes[1], 0);
        commitment_signed_dance!(nodes[1], nodes[2], updates.commitment_signed, true);

        // node[0] <- update_fail_htlcs -- node[1]
        let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
        check_added_monitors!(nodes[0], 0);
        commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, false);

        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events.drain(..).next().unwrap() {
                crate::events::Event::ProbeSuccessful { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
                        assert_eq!(payment_id, ev_pid);
                        assert_eq!(payment_hash, ev_ph);
                },
                _ => panic!(),
        };
        assert!(!nodes[0].node.has_pending_payments());
}

#[test]
fn failed_probe_yields_event() {
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 100000, 90000000);

        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), 42);

        let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 9_998_000);

        let (payment_hash, payment_id) = nodes[0].node.send_probe(route.paths[0].clone()).unwrap();

        // node[0] -- update_add_htlcs -> node[1]
        check_added_monitors!(nodes[0], 1);
        let updates = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let probe_event = SendEvent::from_commitment_update(nodes[1].node.get_our_node_id(), updates);
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &probe_event.msgs[0]);
        check_added_monitors!(nodes[1], 0);
        commitment_signed_dance!(nodes[1], nodes[0], probe_event.commitment_msg, false);
        expect_pending_htlcs_forwardable!(nodes[1]);

        // node[0] <- update_fail_htlcs -- node[1]
        check_added_monitors!(nodes[1], 1);
        let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        // Skip the PendingHTLCsForwardable event
        let _events = nodes[1].node.get_and_clear_pending_events();
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
        check_added_monitors!(nodes[0], 0);
        commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, false);

        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events.drain(..).next().unwrap() {
                crate::events::Event::ProbeFailed { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
                        assert_eq!(payment_id, ev_pid);
                        assert_eq!(payment_hash, ev_ph);
                },
                _ => panic!(),
        };
        assert!(!nodes[0].node.has_pending_payments());
}

#[test]
fn onchain_failed_probe_yields_event() {
        // Tests that an attempt to probe over a channel that is eventaully closed results in a failure
        // event.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let chan_id = create_announced_chan_between_nodes(&nodes, 0, 1).2;
        create_announced_chan_between_nodes(&nodes, 1, 2);

        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), 42);

        // Send a dust HTLC, which will be treated as if it timed out once the channel hits the chain.
        let (route, _, _, _) = get_route_and_payment_hash!(&nodes[0], nodes[2], &payment_params, 1_000);
        let (payment_hash, payment_id) = nodes[0].node.send_probe(route.paths[0].clone()).unwrap();

        // node[0] -- update_add_htlcs -> node[1]
        check_added_monitors!(nodes[0], 1);
        let updates = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
        let probe_event = SendEvent::from_commitment_update(nodes[1].node.get_our_node_id(), updates);
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &probe_event.msgs[0]);
        check_added_monitors!(nodes[1], 0);
        commitment_signed_dance!(nodes[1], nodes[0], probe_event.commitment_msg, false);
        expect_pending_htlcs_forwardable!(nodes[1]);

        check_added_monitors!(nodes[1], 1);
        let _ = get_htlc_update_msgs!(nodes[1], nodes[2].node.get_our_node_id());

        // Don't bother forwarding the HTLC onwards and just confirm the force-close transaction on
        // Node A, which after 6 confirmations should result in a probe failure event.
        let bs_txn = get_local_commitment_txn!(nodes[1], chan_id);
        confirm_transaction(&nodes[0], &bs_txn[0]);
        check_closed_broadcast!(&nodes[0], true);
        check_added_monitors!(nodes[0], 1);

        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 2);
        let mut found_probe_failed = false;
        for event in events.drain(..) {
                match event {
                        Event::ProbeFailed { payment_id: ev_pid, payment_hash: ev_ph, .. } => {
                                assert_eq!(payment_id, ev_pid);
                                assert_eq!(payment_hash, ev_ph);
                                found_probe_failed = true;
                        },
                        Event::ChannelClosed { .. } => {},
                        _ => panic!(),
                }
        }
        assert!(found_probe_failed);
        assert!(!nodes[0].node.has_pending_payments());
}

#[test]
fn claimed_send_payment_idempotent() {
        // Tests that `send_payment` (and friends) are (reasonably) idempotent.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1).2;

        let (route, second_payment_hash, second_payment_preimage, second_payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);
        let (first_payment_preimage, _, _, payment_id) = send_along_route(&nodes[0], route.clone(), &[&nodes[1]], 100_000);

        macro_rules! check_send_rejected {
                () => {
                        // If we try to resend a new payment with a different payment_hash but with the same
                        // payment_id, it should be rejected.
                        let send_result = nodes[0].node.send_payment_with_route(&route, second_payment_hash,
                                RecipientOnionFields::secret_only(second_payment_secret), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
                        }

                        // Further, if we try to send a spontaneous payment with the same payment_id it should
                        // also be rejected.
                        let send_result = nodes[0].node.send_spontaneous_payment(
                                &route, None, RecipientOnionFields::spontaneous_empty(), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
                        }
                }
        }

        check_send_rejected!();

        // Claim the payment backwards, but note that the PaymentSent event is still pending and has
        // not been seen by the user. At this point, from the user perspective nothing has changed, so
        // we must remain just as idempotent as we were before.
        do_claim_payment_along_route(&nodes[0], &[&[&nodes[1]]], false, first_payment_preimage);

        for _ in 0..=IDEMPOTENCY_TIMEOUT_TICKS {
                nodes[0].node.timer_tick_occurred();
        }

        check_send_rejected!();

        // Once the user sees and handles the `PaymentSent` event, we expect them to no longer call
        // `send_payment`, and our idempotency guarantees are off - they should have atomically marked
        // the payment complete. However, they could have called `send_payment` while the event was
        // being processed, leading to a race in our idempotency guarantees. Thus, even immediately
        // after the event is handled a duplicate payment should sitll be rejected.
        expect_payment_sent!(&nodes[0], first_payment_preimage, Some(0));
        check_send_rejected!();

        // If relatively little time has passed, a duplicate payment should still fail.
        nodes[0].node.timer_tick_occurred();
        check_send_rejected!();

        // However, after some time has passed (at least more than the one timer tick above), a
        // duplicate payment should go through, as ChannelManager should no longer have any remaining
        // references to the old payment data.
        for _ in 0..IDEMPOTENCY_TIMEOUT_TICKS {
                nodes[0].node.timer_tick_occurred();
        }

        nodes[0].node.send_payment_with_route(&route, second_payment_hash,
                RecipientOnionFields::secret_only(second_payment_secret), payment_id).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1]]], 100_000, second_payment_hash, second_payment_secret);
        claim_payment(&nodes[0], &[&nodes[1]], second_payment_preimage);
}

#[test]
fn abandoned_send_payment_idempotent() {
        // Tests that `send_payment` (and friends) allow duplicate PaymentIds immediately after
        // abandon_payment.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1).2;

        let (route, second_payment_hash, second_payment_preimage, second_payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);
        let (_, first_payment_hash, _, payment_id) = send_along_route(&nodes[0], route.clone(), &[&nodes[1]], 100_000);

        macro_rules! check_send_rejected {
                () => {
                        // If we try to resend a new payment with a different payment_hash but with the same
                        // payment_id, it should be rejected.
                        let send_result = nodes[0].node.send_payment_with_route(&route, second_payment_hash,
                                RecipientOnionFields::secret_only(second_payment_secret), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
                        }

                        // Further, if we try to send a spontaneous payment with the same payment_id it should
                        // also be rejected.
                        let send_result = nodes[0].node.send_spontaneous_payment(
                                &route, None, RecipientOnionFields::spontaneous_empty(), payment_id);
                        match send_result {
                                Err(PaymentSendFailure::DuplicatePayment) => {},
                                _ => panic!("Unexpected send result: {:?}", send_result),
                        }
                }
        }

        check_send_rejected!();

        nodes[1].node.fail_htlc_backwards(&first_payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], [HTLCDestination::FailedPayment { payment_hash: first_payment_hash }]);

        // Until we abandon the payment upon path failure, no matter how many timer ticks pass, we still cannot reuse the
        // PaymentId.
        for _ in 0..=IDEMPOTENCY_TIMEOUT_TICKS {
                nodes[0].node.timer_tick_occurred();
        }
        check_send_rejected!();

        pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, first_payment_hash, PaymentFailureReason::RecipientRejected);

        // However, we can reuse the PaymentId immediately after we `abandon_payment` upon passing the
        // failed payment back.
        nodes[0].node.send_payment_with_route(&route, second_payment_hash,
                RecipientOnionFields::secret_only(second_payment_secret), payment_id).unwrap();
        check_added_monitors!(nodes[0], 1);
        pass_along_route(&nodes[0], &[&[&nodes[1]]], 100_000, second_payment_hash, second_payment_secret);
        claim_payment(&nodes[0], &[&nodes[1]], second_payment_preimage);
}

#[derive(PartialEq)]
enum InterceptTest {
        Forward,
        Fail,
        Timeout,
}

#[test]
fn test_trivial_inflight_htlc_tracking(){
        // In this test, we test three scenarios:
        // (1) Sending + claiming a payment successfully should return `None` when querying InFlightHtlcs
        // (2) Sending a payment without claiming it should return the payment's value (500000) when querying InFlightHtlcs
        // (3) After we claim the payment sent in (2), InFlightHtlcs should return `None` for the query.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let (_, _, chan_1_id, _) = create_announced_chan_between_nodes(&nodes, 0, 1);
        let (_, _, chan_2_id, _) = create_announced_chan_between_nodes(&nodes, 1, 2);

        // Send and claim the payment. Inflight HTLCs should be empty.
        let payment_hash = send_payment(&nodes[0], &[&nodes[1], &nodes[2]], 500000).1;
        let inflight_htlcs = node_chanmgrs[0].compute_inflight_htlcs();
        {
                let mut node_0_per_peer_lock;
                let mut node_0_peer_state_lock;
                let channel_1 =  get_channel_ref!(&nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, chan_1_id);

                let chan_1_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[0].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
                        channel_1.context.get_short_channel_id().unwrap()
                );
                assert_eq!(chan_1_used_liquidity, None);
        }
        {
                let mut node_1_per_peer_lock;
                let mut node_1_peer_state_lock;
                let channel_2 =  get_channel_ref!(&nodes[1], nodes[2], node_1_per_peer_lock, node_1_peer_state_lock, chan_2_id);

                let chan_2_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[2].node.get_our_node_id()),
                        channel_2.context.get_short_channel_id().unwrap()
                );

                assert_eq!(chan_2_used_liquidity, None);
        }
        let pending_payments = nodes[0].node.list_recent_payments();
        assert_eq!(pending_payments.len(), 1);
        assert_eq!(pending_payments[0], RecentPaymentDetails::Fulfilled { payment_hash: Some(payment_hash) });

        // Remove fulfilled payment
        for _ in 0..=IDEMPOTENCY_TIMEOUT_TICKS {
                nodes[0].node.timer_tick_occurred();
        }

        // Send the payment, but do not claim it. Our inflight HTLCs should contain the pending payment.
        let (payment_preimage, payment_hash,  _) = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 500000);
        let inflight_htlcs = node_chanmgrs[0].compute_inflight_htlcs();
        {
                let mut node_0_per_peer_lock;
                let mut node_0_peer_state_lock;
                let channel_1 =  get_channel_ref!(&nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, chan_1_id);

                let chan_1_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[0].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
                        channel_1.context.get_short_channel_id().unwrap()
                );
                // First hop accounts for expected 1000 msat fee
                assert_eq!(chan_1_used_liquidity, Some(501000));
        }
        {
                let mut node_1_per_peer_lock;
                let mut node_1_peer_state_lock;
                let channel_2 =  get_channel_ref!(&nodes[1], nodes[2], node_1_per_peer_lock, node_1_peer_state_lock, chan_2_id);

                let chan_2_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[2].node.get_our_node_id()),
                        channel_2.context.get_short_channel_id().unwrap()
                );

                assert_eq!(chan_2_used_liquidity, Some(500000));
        }
        let pending_payments = nodes[0].node.list_recent_payments();
        assert_eq!(pending_payments.len(), 1);
        assert_eq!(pending_payments[0], RecentPaymentDetails::Pending { payment_hash, total_msat: 500000 });

        // Now, let's claim the payment. This should result in the used liquidity to return `None`.
        claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage);

        // Remove fulfilled payment
        for _ in 0..=IDEMPOTENCY_TIMEOUT_TICKS {
                nodes[0].node.timer_tick_occurred();
        }

        let inflight_htlcs = node_chanmgrs[0].compute_inflight_htlcs();
        {
                let mut node_0_per_peer_lock;
                let mut node_0_peer_state_lock;
                let channel_1 =  get_channel_ref!(&nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, chan_1_id);

                let chan_1_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[0].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
                        channel_1.context.get_short_channel_id().unwrap()
                );
                assert_eq!(chan_1_used_liquidity, None);
        }
        {
                let mut node_1_per_peer_lock;
                let mut node_1_peer_state_lock;
                let channel_2 =  get_channel_ref!(&nodes[1], nodes[2], node_1_per_peer_lock, node_1_peer_state_lock, chan_2_id);

                let chan_2_used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[2].node.get_our_node_id()),
                        channel_2.context.get_short_channel_id().unwrap()
                );
                assert_eq!(chan_2_used_liquidity, None);
        }

        let pending_payments = nodes[0].node.list_recent_payments();
        assert_eq!(pending_payments.len(), 0);
}

#[test]
fn test_holding_cell_inflight_htlcs() {
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);
        let channel_id = create_announced_chan_between_nodes(&nodes, 0, 1).2;

        let (route, payment_hash_1, _, payment_secret_1) = get_route_and_payment_hash!(nodes[0], nodes[1], 1000000);
        let (_, payment_hash_2, payment_secret_2) = get_payment_preimage_hash!(nodes[1]);

        // Queue up two payments - one will be delivered right away, one immediately goes into the
        // holding cell as nodes[0] is AwaitingRAA.
        {
                nodes[0].node.send_payment_with_route(&route, payment_hash_1,
                        RecipientOnionFields::secret_only(payment_secret_1), PaymentId(payment_hash_1.0)).unwrap();
                check_added_monitors!(nodes[0], 1);
                nodes[0].node.send_payment_with_route(&route, payment_hash_2,
                        RecipientOnionFields::secret_only(payment_secret_2), PaymentId(payment_hash_2.0)).unwrap();
                check_added_monitors!(nodes[0], 0);
        }

        let inflight_htlcs = node_chanmgrs[0].compute_inflight_htlcs();

        {
                let mut node_0_per_peer_lock;
                let mut node_0_peer_state_lock;
                let channel =  get_channel_ref!(&nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, channel_id);

                let used_liquidity = inflight_htlcs.used_liquidity_msat(
                        &NodeId::from_pubkey(&nodes[0].node.get_our_node_id()) ,
                        &NodeId::from_pubkey(&nodes[1].node.get_our_node_id()),
                        channel.context.get_short_channel_id().unwrap()
                );

                assert_eq!(used_liquidity, Some(2000000));
        }

        // Clear pending events so test doesn't throw a "Had excess message on node..." error
        nodes[0].node.get_and_clear_pending_msg_events();
}

#[test]
fn intercepted_payment() {
        // Test that detecting an intercept scid on payment forward will signal LDK to generate an
        // intercept event, which the LSP can then use to either (a) open a JIT channel to forward the
        // payment or (b) fail the payment.
        do_test_intercepted_payment(InterceptTest::Forward);
        do_test_intercepted_payment(InterceptTest::Fail);
        // Make sure that intercepted payments will be automatically failed back if too many blocks pass.
        do_test_intercepted_payment(InterceptTest::Timeout);
}

fn do_test_intercepted_payment(test: InterceptTest) {
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);

        let mut zero_conf_chan_config = test_default_channel_config();
        zero_conf_chan_config.manually_accept_inbound_channels = true;
        let mut intercept_forwards_config = test_default_channel_config();
        intercept_forwards_config.accept_intercept_htlcs = true;
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, Some(intercept_forwards_config), Some(zero_conf_chan_config)]);

        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        let scorer = test_utils::TestScorer::new();
        let random_seed_bytes = chanmon_cfgs[0].keys_manager.get_secure_random_bytes();

        let _ = create_announced_chan_between_nodes(&nodes, 0, 1).2;

        let amt_msat = 100_000;
        let intercept_scid = nodes[1].node.get_intercept_scid();
        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_route_hints(vec![
                        RouteHint(vec![RouteHintHop {
                                src_node_id: nodes[1].node.get_our_node_id(),
                                short_channel_id: intercept_scid,
                                fees: RoutingFees {
                                        base_msat: 1000,
                                        proportional_millionths: 0,
                                },
                                cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
                                htlc_minimum_msat: None,
                                htlc_maximum_msat: None,
                        }])
                ]).unwrap()
                .with_bolt11_features(nodes[2].node.invoice_features()).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };
        let route = get_route(
                &nodes[0].node.get_our_node_id(), &route_params.payment_params,
                &nodes[0].network_graph.read_only(), None, route_params.final_value_msat,
                nodes[0].logger, &scorer, &(), &random_seed_bytes,
        ).unwrap();

        let (payment_hash, payment_secret) = nodes[2].node.create_inbound_payment(Some(amt_msat), 60 * 60, None).unwrap();
        nodes[0].node.send_payment_with_route(&route, payment_hash,
                RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)).unwrap();
        let payment_event = {
                {
                        let mut added_monitors = nodes[0].chain_monitor.added_monitors.lock().unwrap();
                        assert_eq!(added_monitors.len(), 1);
                        added_monitors.clear();
                }
                let mut events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(events.len(), 1);
                SendEvent::from_event(events.remove(0))
        };
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], &payment_event.commitment_msg, false, true);

        // Check that we generate the PaymentIntercepted event when an intercept forward is detected.
        let events = nodes[1].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        let (intercept_id, expected_outbound_amount_msat) = match events[0] {
                crate::events::Event::HTLCIntercepted {
                        intercept_id, expected_outbound_amount_msat, payment_hash: pmt_hash, inbound_amount_msat, requested_next_hop_scid: short_channel_id
                } => {
                        assert_eq!(pmt_hash, payment_hash);
                        assert_eq!(inbound_amount_msat, route.get_total_amount() + route.get_total_fees());
                        assert_eq!(short_channel_id, intercept_scid);
                        (intercept_id, expected_outbound_amount_msat)
                },
                _ => panic!()
        };

        // Check for unknown channel id error.
        let unknown_chan_id_err = nodes[1].node.forward_intercepted_htlc(intercept_id, &[42; 32], nodes[2].node.get_our_node_id(), expected_outbound_amount_msat).unwrap_err();
        assert_eq!(unknown_chan_id_err , APIError::ChannelUnavailable  {
                err: format!("Funded channel with id {} not found for the passed counterparty node_id {}. Channel may still be opening.",
                        log_bytes!([42; 32]), nodes[2].node.get_our_node_id()) });

        if test == InterceptTest::Fail {
                // Ensure we can fail the intercepted payment back.
                nodes[1].node.fail_intercepted_htlc(intercept_id).unwrap();
                expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1], vec![HTLCDestination::UnknownNextHop { requested_forward_scid: intercept_scid }]);
                nodes[1].node.process_pending_htlc_forwards();
                let update_fail = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                check_added_monitors!(&nodes[1], 1);
                assert!(update_fail.update_fail_htlcs.len() == 1);
                let fail_msg = update_fail.update_fail_htlcs[0].clone();
                nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
                commitment_signed_dance!(nodes[0], nodes[1], update_fail.commitment_signed, false);

                // Ensure the payment fails with the expected error.
                let fail_conditions = PaymentFailedConditions::new()
                        .blamed_scid(intercept_scid)
                        .blamed_chan_closed(true)
                        .expected_htlc_error_data(0x4000 | 10, &[]);
                expect_payment_failed_conditions(&nodes[0], payment_hash, false, fail_conditions);
        } else if test == InterceptTest::Forward {
                // Check that we'll fail as expected when sending to a channel that isn't in `ChannelReady` yet.
                let temp_chan_id = nodes[1].node.create_channel(nodes[2].node.get_our_node_id(), 100_000, 0, 42, None).unwrap();
                let unusable_chan_err = nodes[1].node.forward_intercepted_htlc(intercept_id, &temp_chan_id, nodes[2].node.get_our_node_id(), expected_outbound_amount_msat).unwrap_err();
                assert_eq!(unusable_chan_err , APIError::ChannelUnavailable {
                        err: format!("Funded channel with id {} not found for the passed counterparty node_id {}. Channel may still be opening.",
                                log_bytes!(temp_chan_id), nodes[2].node.get_our_node_id()) });
                assert_eq!(nodes[1].node.get_and_clear_pending_msg_events().len(), 1);

                // Open the just-in-time channel so the payment can then be forwarded.
                let (_, channel_id) = open_zero_conf_channel(&nodes[1], &nodes[2], None);

                // Finally, forward the intercepted payment through and claim it.
                nodes[1].node.forward_intercepted_htlc(intercept_id, &channel_id, nodes[2].node.get_our_node_id(), expected_outbound_amount_msat).unwrap();
                expect_pending_htlcs_forwardable!(nodes[1]);

                let payment_event = {
                        {
                                let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
                                assert_eq!(added_monitors.len(), 1);
                                added_monitors.clear();
                        }
                        let mut events = nodes[1].node.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        SendEvent::from_event(events.remove(0))
                };
                nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &payment_event.msgs[0]);
                commitment_signed_dance!(nodes[2], nodes[1], &payment_event.commitment_msg, false, true);
                expect_pending_htlcs_forwardable!(nodes[2]);

                let payment_preimage = nodes[2].node.get_payment_preimage(payment_hash, payment_secret).unwrap();
                expect_payment_claimable!(&nodes[2], payment_hash, payment_secret, amt_msat, Some(payment_preimage), nodes[2].node.get_our_node_id());
                do_claim_payment_along_route(&nodes[0], &vec!(&vec!(&nodes[1], &nodes[2])[..]), false, payment_preimage);
                let events = nodes[0].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 2);
                match events[0] {
                        Event::PaymentSent { payment_preimage: ref ev_preimage, payment_hash: ref ev_hash, ref fee_paid_msat, .. } => {
                                assert_eq!(payment_preimage, *ev_preimage);
                                assert_eq!(payment_hash, *ev_hash);
                                assert_eq!(fee_paid_msat, &Some(1000));
                        },
                        _ => panic!("Unexpected event")
                }
                match events[1] {
                        Event::PaymentPathSuccessful { payment_hash: hash, .. } => {
                                assert_eq!(hash, Some(payment_hash));
                        },
                        _ => panic!("Unexpected event")
                }
        } else if test == InterceptTest::Timeout {
                let mut block = create_dummy_block(nodes[0].best_block_hash(), 42, Vec::new());
                connect_block(&nodes[0], &block);
                connect_block(&nodes[1], &block);
                for _ in 0..TEST_FINAL_CLTV {
                        block.header.prev_blockhash = block.block_hash();
                        connect_block(&nodes[0], &block);
                        connect_block(&nodes[1], &block);
                }
                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::InvalidForward { requested_forward_scid: intercept_scid }]);
                check_added_monitors!(nodes[1], 1);
                let htlc_timeout_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                assert!(htlc_timeout_updates.update_add_htlcs.is_empty());
                assert_eq!(htlc_timeout_updates.update_fail_htlcs.len(), 1);
                assert!(htlc_timeout_updates.update_fail_malformed_htlcs.is_empty());
                assert!(htlc_timeout_updates.update_fee.is_none());

                nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &htlc_timeout_updates.update_fail_htlcs[0]);
                commitment_signed_dance!(nodes[0], nodes[1], htlc_timeout_updates.commitment_signed, false);
                expect_payment_failed!(nodes[0], payment_hash, false, 0x2000 | 2, []);

                // Check for unknown intercept id error.
                let (_, channel_id) = open_zero_conf_channel(&nodes[1], &nodes[2], None);
                let unknown_intercept_id_err = nodes[1].node.forward_intercepted_htlc(intercept_id, &channel_id, nodes[2].node.get_our_node_id(), expected_outbound_amount_msat).unwrap_err();
                assert_eq!(unknown_intercept_id_err , APIError::APIMisuseError { err: format!("Payment with intercept id {} not found", log_bytes!(intercept_id.0)) });
                let unknown_intercept_id_err = nodes[1].node.fail_intercepted_htlc(intercept_id).unwrap_err();
                assert_eq!(unknown_intercept_id_err , APIError::APIMisuseError { err: format!("Payment with intercept id {} not found", log_bytes!(intercept_id.0)) });
        }
}

#[test]
fn accept_underpaying_htlcs_config() {
        do_accept_underpaying_htlcs_config(1);
        do_accept_underpaying_htlcs_config(2);
        do_accept_underpaying_htlcs_config(3);
}

fn do_accept_underpaying_htlcs_config(num_mpp_parts: usize) {
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let mut intercept_forwards_config = test_default_channel_config();
        intercept_forwards_config.accept_intercept_htlcs = true;
        let mut underpay_config = test_default_channel_config();
        underpay_config.channel_config.accept_underpaying_htlcs = true;
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, Some(intercept_forwards_config), Some(underpay_config)]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let mut chan_ids = Vec::new();
        for _ in 0..num_mpp_parts {
                let _ = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000, 0);
                let channel_id = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 2, 2_000_000, 0).0.channel_id;
                chan_ids.push(channel_id);
        }

        // Send the initial payment.
        let amt_msat = 900_000;
        let skimmed_fee_msat = 20;
        let mut route_hints = Vec::new();
        for _ in 0..num_mpp_parts {
                route_hints.push(RouteHint(vec![RouteHintHop {
                        src_node_id: nodes[1].node.get_our_node_id(),
                        short_channel_id: nodes[1].node.get_intercept_scid(),
                        fees: RoutingFees {
                                base_msat: 1000,
                                proportional_millionths: 0,
                        },
                        cltv_expiry_delta: MIN_CLTV_EXPIRY_DELTA,
                        htlc_minimum_msat: None,
                        htlc_maximum_msat: Some(amt_msat / num_mpp_parts as u64 + 5),
                }]));
        }
        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_route_hints(route_hints).unwrap()
                .with_bolt11_features(nodes[2].node.invoice_features()).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };
        let (payment_hash, payment_secret) = nodes[2].node.create_inbound_payment(Some(amt_msat), 60 * 60, None).unwrap();
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
        check_added_monitors!(nodes[0], num_mpp_parts); // one monitor per path
        let mut events: Vec<SendEvent> = nodes[0].node.get_and_clear_pending_msg_events().into_iter().map(|e| SendEvent::from_event(e)).collect();
        assert_eq!(events.len(), num_mpp_parts);

        // Forward the intercepted payments.
        for (idx, ev) in events.into_iter().enumerate() {
                nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &ev.msgs[0]);
                do_commitment_signed_dance(&nodes[1], &nodes[0], &ev.commitment_msg, false, true);

                let events = nodes[1].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 1);
                let (intercept_id, expected_outbound_amt_msat) = match events[0] {
                        crate::events::Event::HTLCIntercepted {
                                intercept_id, expected_outbound_amount_msat, payment_hash: pmt_hash, ..
                        } => {
                                assert_eq!(pmt_hash, payment_hash);
                                (intercept_id, expected_outbound_amount_msat)
                        },
                        _ => panic!()
                };
                nodes[1].node.forward_intercepted_htlc(intercept_id, &chan_ids[idx],
                        nodes[2].node.get_our_node_id(), expected_outbound_amt_msat - skimmed_fee_msat).unwrap();
                expect_pending_htlcs_forwardable!(nodes[1]);
                let payment_event = {
                        {
                                let mut added_monitors = nodes[1].chain_monitor.added_monitors.lock().unwrap();
                                assert_eq!(added_monitors.len(), 1);
                                added_monitors.clear();
                        }
                        let mut events = nodes[1].node.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        SendEvent::from_event(events.remove(0))
                };
                nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &payment_event.msgs[0]);
                do_commitment_signed_dance(&nodes[2], &nodes[1], &payment_event.commitment_msg, false, true);
                if idx == num_mpp_parts - 1 {
                        expect_pending_htlcs_forwardable!(nodes[2]);
                }
        }

        // Claim the payment and check that the skimmed fee is as expected.
        let payment_preimage = nodes[2].node.get_payment_preimage(payment_hash, payment_secret).unwrap();
        let events = nodes[2].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events[0] {
                crate::events::Event::PaymentClaimable {
                        ref payment_hash, ref purpose, amount_msat, counterparty_skimmed_fee_msat, receiver_node_id, ..
                } => {
                        assert_eq!(payment_hash, payment_hash);
                        assert_eq!(amt_msat - skimmed_fee_msat * num_mpp_parts as u64, amount_msat);
                        assert_eq!(skimmed_fee_msat * num_mpp_parts as u64, counterparty_skimmed_fee_msat);
                        assert_eq!(nodes[2].node.get_our_node_id(), receiver_node_id.unwrap());
                        match purpose {
                                crate::events::PaymentPurpose::InvoicePayment { payment_preimage: ev_payment_preimage,
                                        payment_secret: ev_payment_secret, .. } =>
                                {
                                        assert_eq!(payment_preimage, ev_payment_preimage.unwrap());
                                        assert_eq!(payment_secret, *ev_payment_secret);
                                },
                                _ => panic!(),
                        }
                },
                _ => panic!("Unexpected event"),
        }
        let mut expected_paths_vecs = Vec::new();
        let mut expected_paths = Vec::new();
        for _ in 0..num_mpp_parts { expected_paths_vecs.push(vec!(&nodes[1], &nodes[2])); }
        for i in 0..num_mpp_parts { expected_paths.push(&expected_paths_vecs[i][..]); }
        let total_fee_msat = do_claim_payment_along_route_with_extra_penultimate_hop_fees(
                &nodes[0], &expected_paths[..], &vec![skimmed_fee_msat as u32; num_mpp_parts][..], false,
                payment_preimage);
        // The sender doesn't know that the penultimate hop took an extra fee.
        expect_payment_sent(&nodes[0], payment_preimage,
                Some(Some(total_fee_msat - skimmed_fee_msat * num_mpp_parts as u64)), true);
}

#[derive(PartialEq)]
enum AutoRetry {
        Success,
        Spontaneous,
        FailAttempts,
        FailTimeout,
        FailOnRestart,
        FailOnRetry,
}

#[test]
fn automatic_retries() {
        do_automatic_retries(AutoRetry::Success);
        do_automatic_retries(AutoRetry::Spontaneous);
        do_automatic_retries(AutoRetry::FailAttempts);
        do_automatic_retries(AutoRetry::FailTimeout);
        do_automatic_retries(AutoRetry::FailOnRestart);
        do_automatic_retries(AutoRetry::FailOnRetry);
}
fn do_automatic_retries(test: AutoRetry) {
        // Test basic automatic payment retries in ChannelManager. See individual `test` variant comments
        // below.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);

        let persister;
        let new_chain_monitor;
        let node_0_deserialized;

        let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
        let channel_id_1 = create_announced_chan_between_nodes(&nodes, 0, 1).2;
        let channel_id_2 = create_announced_chan_between_nodes(&nodes, 2, 1).2;

        // Marshall data to send the payment
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let amt_msat = 1000;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };
        let (_, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], amt_msat);

        macro_rules! pass_failed_attempt_with_retry_along_path {
                ($failing_channel_id: expr, $expect_pending_htlcs_forwardable: expr) => {
                        // Send a payment attempt that fails due to lack of liquidity on the second hop
                        check_added_monitors!(nodes[0], 1);
                        let update_0 = get_htlc_update_msgs!(nodes[0], nodes[1].node.get_our_node_id());
                        let mut update_add = update_0.update_add_htlcs[0].clone();
                        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &update_add);
                        commitment_signed_dance!(nodes[1], nodes[0], &update_0.commitment_signed, false, true);
                        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
                        nodes[1].node.process_pending_htlc_forwards();
                        expect_pending_htlcs_forwardable_and_htlc_handling_failed_ignore!(nodes[1],
                                vec![HTLCDestination::NextHopChannel {
                                        node_id: Some(nodes[2].node.get_our_node_id()),
                                        channel_id: $failing_channel_id,
                                }]);
                        nodes[1].node.process_pending_htlc_forwards();
                        let update_1 = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                        check_added_monitors!(&nodes[1], 1);
                        assert!(update_1.update_fail_htlcs.len() == 1);
                        let fail_msg = update_1.update_fail_htlcs[0].clone();
                        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_msg);
                        commitment_signed_dance!(nodes[0], nodes[1], update_1.commitment_signed, false);

                        // Ensure the attempt fails and a new PendingHTLCsForwardable event is generated for the retry
                        let mut events = nodes[0].node.get_and_clear_pending_events();
                        assert_eq!(events.len(), 2);
                        match events[0] {
                                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
                                        assert_eq!(payment_hash, ev_payment_hash);
                                        assert_eq!(payment_failed_permanently, false);
                                },
                                _ => panic!("Unexpected event"),
                        }
                        if $expect_pending_htlcs_forwardable {
                                match events[1] {
                                        Event::PendingHTLCsForwardable { .. } => {},
                                        _ => panic!("Unexpected event"),
                                }
                        } else {
                                match events[1] {
                                        Event::PaymentFailed { payment_hash: ev_payment_hash, .. } => {
                                                assert_eq!(payment_hash, ev_payment_hash);
                                        },
                                        _ => panic!("Unexpected event"),
                                }
                        }
                }
        }

        if test == AutoRetry::Success {
                // Test that we can succeed on the first retry.
                nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                        PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                // Open a new channel with liquidity on the second hop so we can find a route for the retry
                // attempt, since the initial second hop channel will be excluded from pathfinding
                create_announced_chan_between_nodes(&nodes, 1, 2);

                // We retry payments in `process_pending_htlc_forwards`
                nodes[0].node.process_pending_htlc_forwards();
                check_added_monitors!(nodes[0], 1);
                let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(msg_events.len(), 1);
                pass_along_path(&nodes[0], &[&nodes[1], &nodes[2]], amt_msat, payment_hash, Some(payment_secret), msg_events.pop().unwrap(), true, None);
                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
        } else if test == AutoRetry::Spontaneous {
                nodes[0].node.send_spontaneous_payment_with_retry(Some(payment_preimage),
                        RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params,
                        Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                // Open a new channel with liquidity on the second hop so we can find a route for the retry
                // attempt, since the initial second hop channel will be excluded from pathfinding
                create_announced_chan_between_nodes(&nodes, 1, 2);

                // We retry payments in `process_pending_htlc_forwards`
                nodes[0].node.process_pending_htlc_forwards();
                check_added_monitors!(nodes[0], 1);
                let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(msg_events.len(), 1);
                pass_along_path(&nodes[0], &[&nodes[1], &nodes[2]], amt_msat, payment_hash, None, msg_events.pop().unwrap(), true, Some(payment_preimage));
                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
        } else if test == AutoRetry::FailAttempts {
                // Ensure ChannelManager will not retry a payment if it has run out of payment attempts.
                nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                        PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                // Open a new channel with no liquidity on the second hop so we can find a (bad) route for
                // the retry attempt, since the initial second hop channel will be excluded from pathfinding
                let channel_id_3 = create_announced_chan_between_nodes(&nodes, 2, 1).2;

                // We retry payments in `process_pending_htlc_forwards`
                nodes[0].node.process_pending_htlc_forwards();
                pass_failed_attempt_with_retry_along_path!(channel_id_3, false);

                // Ensure we won't retry a second time.
                nodes[0].node.process_pending_htlc_forwards();
                let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(msg_events.len(), 0);
        } else if test == AutoRetry::FailTimeout {
                #[cfg(not(feature = "no-std"))] {
                        // Ensure ChannelManager will not retry a payment if it times out due to Retry::Timeout.
                        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                                PaymentId(payment_hash.0), route_params, Retry::Timeout(Duration::from_secs(60))).unwrap();
                        pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                        // Advance the time so the second attempt fails due to timeout.
                        SinceEpoch::advance(Duration::from_secs(61));

                        // Make sure we don't retry again.
                        nodes[0].node.process_pending_htlc_forwards();
                        let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                        assert_eq!(msg_events.len(), 0);

                        let mut events = nodes[0].node.get_and_clear_pending_events();
                        assert_eq!(events.len(), 1);
                        match events[0] {
                                Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                        assert_eq!(payment_hash, *ev_payment_hash);
                                        assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
                                        assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                                },
                                _ => panic!("Unexpected event"),
                        }
                }
        } else if test == AutoRetry::FailOnRestart {
                // Ensure ChannelManager will not retry a payment after restart, even if there were retry
                // attempts remaining prior to restart.
                nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                        PaymentId(payment_hash.0), route_params, Retry::Attempts(2)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                // Open a new channel with no liquidity on the second hop so we can find a (bad) route for
                // the retry attempt, since the initial second hop channel will be excluded from pathfinding
                let channel_id_3 = create_announced_chan_between_nodes(&nodes, 2, 1).2;

                // Ensure the first retry attempt fails, with 1 retry attempt remaining
                nodes[0].node.process_pending_htlc_forwards();
                pass_failed_attempt_with_retry_along_path!(channel_id_3, true);

                // Restart the node and ensure that ChannelManager does not use its remaining retry attempt
                let node_encoded = nodes[0].node.encode();
                let chan_1_monitor_serialized = get_monitor!(nodes[0], channel_id_1).encode();
                reload_node!(nodes[0], node_encoded, &[&chan_1_monitor_serialized], persister, new_chain_monitor, node_0_deserialized);

                let mut events = nodes[0].node.get_and_clear_pending_events();
                expect_pending_htlcs_forwardable_from_events!(nodes[0], events, true);
                // Make sure we don't retry again.
                let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(msg_events.len(), 0);

                let mut events = nodes[0].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 1);
                match events[0] {
                        Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                assert_eq!(payment_hash, *ev_payment_hash);
                                assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
                                assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                        },
                        _ => panic!("Unexpected event"),
                }
        } else if test == AutoRetry::FailOnRetry {
                nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                        PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
                pass_failed_attempt_with_retry_along_path!(channel_id_2, true);

                // We retry payments in `process_pending_htlc_forwards`. Since our channel closed, we should
                // fail to find a route.
                nodes[0].node.process_pending_htlc_forwards();
                let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                assert_eq!(msg_events.len(), 0);

                let mut events = nodes[0].node.get_and_clear_pending_events();
                assert_eq!(events.len(), 1);
                match events[0] {
                        Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                                assert_eq!(payment_hash, *ev_payment_hash);
                                assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
                                assert_eq!(PaymentFailureReason::RouteNotFound, ev_reason.unwrap());
                        },
                        _ => panic!("Unexpected event"),
                }
        }
}

#[test]
fn auto_retry_partial_failure() {
        // Test that we'll retry appropriately on send partial failure and retry partial failure.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let chan_1_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
        let chan_2_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
        let chan_3_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;

        // Marshall data to send the payment
        let amt_msat = 20_000;
        let (_, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        // Ensure the first monitor update (for the initial send path1 over chan_1) succeeds, but the
        // second (for the initial send path2 over chan_2) fails.
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::PermanentFailure);
        // Ensure third monitor update (for the retry1's path1 over chan_1) succeeds, but the fourth (for
        // the retry1's path2 over chan_3) fails, and monitor updates succeed after that.
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::PermanentFailure);
        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);

        // Configure the initial send, retry1 and retry2's paths.
        let send_route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 2,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_2_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 2,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
        let retry_1_route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_3_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
        let retry_2_route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_id,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: amt_msat / 4,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                ],
                payment_params: Some(route_params.payment_params.clone()),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(send_route));
        let mut payment_params = route_params.payment_params.clone();
        payment_params.previously_failed_channels.push(chan_2_id);
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params, final_value_msat: amt_msat / 2,
                }, Ok(retry_1_route));
        let mut payment_params = route_params.payment_params.clone();
        payment_params.previously_failed_channels.push(chan_3_id);
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params, final_value_msat: amt_msat / 4,
                }, Ok(retry_2_route));

        // Send a payment that will partially fail on send, then partially fail on retry, then succeed.
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(3)).unwrap();
        let closed_chan_events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(closed_chan_events.len(), 4);
        match closed_chan_events[0] {
                Event::ChannelClosed { .. } => {},
                _ => panic!("Unexpected event"),
        }
        match closed_chan_events[1] {
                Event::PaymentPathFailed { .. } => {},
                _ => panic!("Unexpected event"),
        }
        match closed_chan_events[2] {
                Event::ChannelClosed { .. } => {},
                _ => panic!("Unexpected event"),
        }
        match closed_chan_events[3] {
                Event::PaymentPathFailed { .. } => {},
                _ => panic!("Unexpected event"),
        }

        // Pass the first part of the payment along the path.
        check_added_monitors!(nodes[0], 5); // three outbound channel updates succeeded, two permanently failed
        let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();

        // First message is the first update_add, remaining messages are broadcasting channel updates and
        // errors for the permfailed channels
        assert_eq!(msg_events.len(), 5);
        let mut payment_event = SendEvent::from_event(msg_events.remove(0));

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &payment_event.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
        check_added_monitors!(nodes[0], 1);
        let as_second_htlc_updates = SendEvent::from_node(&nodes[0]);

        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
        check_added_monitors!(nodes[0], 1);
        let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
        check_added_monitors!(nodes[1], 1);

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &as_second_htlc_updates.msgs[0]);
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &as_second_htlc_updates.msgs[1]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_second_htlc_updates.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let (bs_second_raa, bs_second_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_cs);
        check_added_monitors!(nodes[0], 1);
        let as_second_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
        check_added_monitors!(nodes[1], 1);

        expect_pending_htlcs_forwardable_ignore!(nodes[1]);
        nodes[1].node.process_pending_htlc_forwards();
        expect_payment_claimable!(nodes[1], payment_hash, payment_secret, amt_msat);
        nodes[1].node.claim_funds(payment_preimage);
        expect_payment_claimed!(nodes[1], payment_hash, amt_msat);
        let bs_claim_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        assert_eq!(bs_claim_update.update_fulfill_htlcs.len(), 1);

        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &bs_claim_update.update_fulfill_htlcs[0]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_claim_update.commitment_signed);
        check_added_monitors!(nodes[0], 1);
        let (as_third_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_third_raa);
        check_added_monitors!(nodes[1], 4);
        let bs_second_claim_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
        check_added_monitors!(nodes[1], 1);
        let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &bs_second_claim_update.update_fulfill_htlcs[0]);
        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &bs_second_claim_update.update_fulfill_htlcs[1]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_claim_update.commitment_signed);
        check_added_monitors!(nodes[0], 1);
        let (as_fourth_raa, as_fourth_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_fourth_raa);
        check_added_monitors!(nodes[1], 1);

        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_fourth_cs);
        check_added_monitors!(nodes[1], 1);
        let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
        check_added_monitors!(nodes[0], 1);
        expect_payment_sent!(nodes[0], payment_preimage);
}

#[test]
fn auto_retry_zero_attempts_send_error() {
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
        create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;

        // Marshall data to send the payment
        let amt_msat = 20_000;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::PermanentFailure);
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
        assert_eq!(nodes[0].node.get_and_clear_pending_msg_events().len(), 2); // channel close messages
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 3);
        if let Event::ChannelClosed { .. } = events[0] { } else { panic!(); }
        if let Event::PaymentPathFailed { .. } = events[1] { } else { panic!(); }
        if let Event::PaymentFailed { .. } = events[2] { } else { panic!(); }
        check_added_monitors!(nodes[0], 2);
}

#[test]
fn fails_paying_after_rejected_by_payee() {
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;

        // Marshall data to send the payment
        let amt_msat = 20_000;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 1);
        let mut events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(events.len(), 1);
        let mut payment_event = SendEvent::from_event(events.pop().unwrap());
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
        check_added_monitors!(nodes[1], 0);
        commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false);
        expect_pending_htlcs_forwardable!(nodes[1]);
        expect_payment_claimable!(&nodes[1], payment_hash, payment_secret, amt_msat);

        nodes[1].node.fail_htlc_backwards(&payment_hash);
        expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], [HTLCDestination::FailedPayment { payment_hash }]);
        pass_failed_payment_back(&nodes[0], &[&[&nodes[1]]], false, payment_hash, PaymentFailureReason::RecipientRejected);
}

#[test]
fn retry_multi_path_single_failed_payment() {
        // Tests that we can/will retry after a single path of an MPP payment failed immediately
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
        let nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
        create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);

        let amt_msat = 100_010_000;

        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params: payment_params.clone(),
                final_value_msat: amt_msat,
        };

        let chans = nodes[0].node.list_usable_channels();
        let mut route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[0].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 10_000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[1].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                ],
                payment_params: Some(payment_params),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        // On retry, split the payment across both channels.
        route.paths[0].hops[0].fee_msat = 50_000_001;
        route.paths[1].hops[0].fee_msat = 50_000_000;
        let mut pay_params = route.payment_params.clone().unwrap();
        pay_params.previously_failed_channels.push(chans[1].short_channel_id.unwrap());
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params: pay_params,
                        // Note that the second request here requests the amount we originally failed to send,
                        // not the amount remaining on the full payment, which should be changed.
                        final_value_msat: 100_000_001,
                }, Ok(route.clone()));

        {
                let scorer = chanmon_cfgs[0].scorer.lock().unwrap();
                // The initial send attempt, 2 paths
                scorer.expect_usage(chans[0].short_channel_id.unwrap(), ChannelUsage { amount_msat: 10_000, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });
                scorer.expect_usage(chans[1].short_channel_id.unwrap(), ChannelUsage { amount_msat: 100_000_001, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });
                // The retry, 2 paths. Ensure that the in-flight HTLC amount is factored in.
                scorer.expect_usage(chans[0].short_channel_id.unwrap(), ChannelUsage { amount_msat: 50_000_001, inflight_htlc_msat: 10_000, effective_capacity: EffectiveCapacity::Unknown });
                scorer.expect_usage(chans[1].short_channel_id.unwrap(), ChannelUsage { amount_msat: 50_000_000, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown });
        }

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events[0] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently: false,
                        failure: PathFailure::InitialSend { err: APIError::ChannelUnavailable { .. }},
                        short_channel_id: Some(expected_scid), .. } =>
                {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(expected_scid, route.paths[1].hops[0].short_channel_id);
                },
                _ => panic!("Unexpected event"),
        }
        let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(htlc_msgs.len(), 2);
        check_added_monitors!(nodes[0], 2);
}

#[test]
fn immediate_retry_on_failure() {
        // Tests that we can/will retry immediately after a failure
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
        let nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
        create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);

        let amt_msat = 100_000_001;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        let chans = nodes[0].node.list_usable_channels();
        let mut route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chans[0].short_channel_id.unwrap(),
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        // On retry, split the payment across both channels.
        route.paths.push(route.paths[0].clone());
        route.paths[0].hops[0].short_channel_id = chans[1].short_channel_id.unwrap();
        route.paths[0].hops[0].fee_msat = 50_000_000;
        route.paths[1].hops[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: pay_params, final_value_msat: amt_msat,
                }, Ok(route.clone()));

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 1);
        match events[0] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently: false,
                        failure: PathFailure::InitialSend { err: APIError::ChannelUnavailable { .. }},
                        short_channel_id: Some(expected_scid), .. } =>
                {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(expected_scid, route.paths[1].hops[0].short_channel_id);
                },
                _ => panic!("Unexpected event"),
        }
        let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(htlc_msgs.len(), 2);
        check_added_monitors!(nodes[0], 2);
}

#[test]
fn no_extra_retries_on_back_to_back_fail() {
        // In a previous release, we had a race where we may exceed the payment retry count if we
        // get two failures in a row with the second indicating that all paths had failed (this field,
        // `all_paths_failed`, has since been removed).
        // Generally, when we give up trying to retry a payment, we don't know for sure what the
        // current state of the ChannelManager event queue is. Specifically, we cannot be sure that
        // there are not multiple additional `PaymentPathFailed` or even `PaymentSent` events
        // pending which we will see later. Thus, when we previously removed the retry tracking map
        // entry after a `all_paths_failed` `PaymentPathFailed` event, we may have dropped the
        // retry entry even though more events for the same payment were still pending. This led to
        // us retrying a payment again even though we'd already given up on it.
        //
        // We now have a separate event - `PaymentFailed` which indicates no HTLCs remain and which
        // is used to remove the payment retry counter entries instead. This tests for the specific
        // excess-retry case while also testing `PaymentFailed` generation.

        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let chan_1_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0).0.contents.short_channel_id;
        let chan_2_scid = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 0).0.contents.short_channel_id;

        let amt_msat = 200_000_000;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[1], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        let mut route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 0, // nodes[1] will fail the payment as we don't pay its fee
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_2_scid,
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 0, // nodes[1] will fail the payment as we don't pay its fee
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_2_scid,
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        let mut second_payment_params = route_params.payment_params.clone();
        second_payment_params.previously_failed_channels = vec![chan_2_scid, chan_2_scid];
        // On retry, we'll only return one path
        route.paths.remove(1);
        route.paths[0].hops[1].fee_msat = amt_msat;
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params: second_payment_params,
                        final_value_msat: amt_msat,
                }, Ok(route.clone()));

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);
        assert_eq!(htlc_updates.msgs.len(), 1);

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &htlc_updates.msgs[0]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &htlc_updates.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
        check_added_monitors!(nodes[0], 1);
        let second_htlc_updates = SendEvent::from_node(&nodes[0]);

        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
        check_added_monitors!(nodes[0], 1);
        let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &second_htlc_updates.msgs[0]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &second_htlc_updates.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
        check_added_monitors!(nodes[1], 1);
        let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_fail_update.commitment_signed);
        check_added_monitors!(nodes[0], 1);
        let (as_second_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
        check_added_monitors!(nodes[1], 1);
        let bs_second_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
        check_added_monitors!(nodes[1], 1);
        let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.update_fail_htlcs[0]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.commitment_signed);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
        check_added_monitors!(nodes[0], 1);
        let (as_third_raa, as_fourth_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_third_raa);
        check_added_monitors!(nodes[1], 1);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_fourth_cs);
        check_added_monitors!(nodes[1], 1);
        let bs_fourth_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_fourth_raa);
        check_added_monitors!(nodes[0], 1);

        // At this point A has sent two HTLCs which both failed due to lack of fee. It now has two
        // pending `PaymentPathFailed` events, one with `all_paths_failed` unset, and the second
        // with it set.
        //
        // Previously, we retried payments in an event consumer, which would retry each
        // `PaymentPathFailed` individually. In that setup, we had retried the payment in response to
        // the first `PaymentPathFailed`, then seen the second `PaymentPathFailed` with
        // `all_paths_failed` set and assumed the payment was completely failed. We ultimately fixed it
        // by adding the `PaymentFailed` event.
        //
        // Because we now retry payments as a batch, we simply return a single-path route in the
        // second, batched, request, have that fail, ensure the payment was abandoned.
        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 3);
        match events[0] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(payment_failed_permanently, false);
                },
                _ => panic!("Unexpected event"),
        }
        match events[1] {
                Event::PendingHTLCsForwardable { .. } => {},
                _ => panic!("Unexpected event"),
        }
        match events[2] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(payment_failed_permanently, false);
                },
                _ => panic!("Unexpected event"),
        }

        nodes[0].node.process_pending_htlc_forwards();
        let retry_htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &retry_htlc_updates.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], &retry_htlc_updates.commitment_msg, false, true);
        let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[0], nodes[1], &bs_fail_update.commitment_signed, false, true);

        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 2);
        match events[0] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(payment_failed_permanently, false);
                },
                _ => panic!("Unexpected event"),
        }
        match events[1] {
                Event::PaymentFailed { payment_hash: ref ev_payment_hash, payment_id: ref ev_payment_id, reason: ref ev_reason } => {
                        assert_eq!(payment_hash, *ev_payment_hash);
                        assert_eq!(PaymentId(payment_hash.0), *ev_payment_id);
                        assert_eq!(PaymentFailureReason::RetriesExhausted, ev_reason.unwrap());
                },
                _ => panic!("Unexpected event"),
        }
}

#[test]
fn test_simple_partial_retry() {
        // In the first version of the in-`ChannelManager` payment retries, retries were sent for the
        // full amount of the payment, rather than only the missing amount. Here we simply test for
        // this by sending a payment with two parts, failing one, and retrying the second. Note that
        // `TestRouter` will check that the `RouteParameters` (which contain the amount) matches the
        // request.
        let chanmon_cfgs = create_chanmon_cfgs(3);
        let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
        let nodes = create_network(3, &node_cfgs, &node_chanmgrs);

        let chan_1_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0).0.contents.short_channel_id;
        let chan_2_scid = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 0).0.contents.short_channel_id;

        let amt_msat = 200_000_000;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[2], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        let mut route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 0, // nodes[1] will fail the payment as we don't pay its fee
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_2_scid,
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 100_000,
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_2_scid,
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000_000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        let mut second_payment_params = route_params.payment_params.clone();
        second_payment_params.previously_failed_channels = vec![chan_2_scid];
        // On retry, we'll only be asked for one path (or 100k sats)
        route.paths.remove(0);
        nodes[0].router.expect_find_route(RouteParameters {
                        payment_params: second_payment_params,
                        final_value_msat: amt_msat / 2,
                }, Ok(route.clone()));

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params, Retry::Attempts(1)).unwrap();
        let htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);
        assert_eq!(htlc_updates.msgs.len(), 1);

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &htlc_updates.msgs[0]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &htlc_updates.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
        check_added_monitors!(nodes[0], 1);
        let second_htlc_updates = SendEvent::from_node(&nodes[0]);

        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
        check_added_monitors!(nodes[0], 1);
        let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &second_htlc_updates.msgs[0]);
        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &second_htlc_updates.commitment_msg);
        check_added_monitors!(nodes[1], 1);
        let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
        check_added_monitors!(nodes[1], 1);
        let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
        check_added_monitors!(nodes[0], 1);

        nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_fail_update.commitment_signed);
        check_added_monitors!(nodes[0], 1);
        let (as_second_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());

        nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
        check_added_monitors!(nodes[1], 1);

        nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
        check_added_monitors!(nodes[1], 1);

        let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());

        nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
        check_added_monitors!(nodes[0], 1);

        let mut events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 2);
        match events[0] {
                Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
                        assert_eq!(payment_hash, ev_payment_hash);
                        assert_eq!(payment_failed_permanently, false);
                },
                _ => panic!("Unexpected event"),
        }
        match events[1] {
                Event::PendingHTLCsForwardable { .. } => {},
                _ => panic!("Unexpected event"),
        }

        nodes[0].node.process_pending_htlc_forwards();
        let retry_htlc_updates = SendEvent::from_node(&nodes[0]);
        check_added_monitors!(nodes[0], 1);

        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &retry_htlc_updates.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], &retry_htlc_updates.commitment_msg, false, true);

        expect_pending_htlcs_forwardable!(nodes[1]);
        check_added_monitors!(nodes[1], 1);

        let bs_forward_update = get_htlc_update_msgs!(nodes[1], nodes[2].node.get_our_node_id());
        nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &bs_forward_update.update_add_htlcs[0]);
        nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &bs_forward_update.update_add_htlcs[1]);
        commitment_signed_dance!(nodes[2], nodes[1], &bs_forward_update.commitment_signed, false);

        expect_pending_htlcs_forwardable!(nodes[2]);
        expect_payment_claimable!(nodes[2], payment_hash, payment_secret, amt_msat);
}

#[test]
#[cfg(feature = "std")]
fn test_threaded_payment_retries() {
        // In the first version of the in-`ChannelManager` payment retries, retries weren't limited to
        // a single thread and would happily let multiple threads run retries at the same time. Because
        // retries are done by first calculating the amount we need to retry, then dropping the
        // relevant lock, then actually sending, we would happily let multiple threads retry the same
        // amount at the same time, overpaying our original HTLC!
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
        let nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        // There is one mitigating guardrail when retrying payments - we can never over-pay by more
        // than 10% of the original value. Thus, we want all our retries to be below that. In order to
        // keep things simple, we route one HTLC for 0.1% of the payment over channel 1 and the rest
        // out over channel 3+4. This will let us ignore 99% of the payment value and deal with only
        // our channel.
        let chan_1_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0).0.contents.short_channel_id;
        create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 10_000_000, 0);
        let chan_3_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 10_000_000, 0).0.contents.short_channel_id;
        let chan_4_scid = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 0).0.contents.short_channel_id;

        let amt_msat = 100_000_000;
        let (_, payment_hash, _, payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[2], amt_msat);
        #[cfg(feature = "std")]
        let payment_expiry_secs = SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() + 60 * 60;
        #[cfg(not(feature = "std"))]
        let payment_expiry_secs = 60 * 60;
        let mut invoice_features = Bolt11InvoiceFeatures::empty();
        invoice_features.set_variable_length_onion_required();
        invoice_features.set_payment_secret_required();
        invoice_features.set_basic_mpp_optional();
        let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_expiry_time(payment_expiry_secs as u64)
                .with_bolt11_features(invoice_features).unwrap();
        let mut route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        let mut route = Route {
                paths: vec![
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[1].node.get_our_node_id(),
                                node_features: nodes[1].node.node_features(),
                                short_channel_id: chan_1_scid,
                                channel_features: nodes[1].node.channel_features(),
                                fee_msat: 0,
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[3].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: 42, // Set a random SCID which nodes[1] will fail as unknown
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: amt_msat / 1000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None },
                        Path { hops: vec![RouteHop {
                                pubkey: nodes[2].node.get_our_node_id(),
                                node_features: nodes[2].node.node_features(),
                                short_channel_id: chan_3_scid,
                                channel_features: nodes[2].node.channel_features(),
                                fee_msat: 100_000,
                                cltv_expiry_delta: 100,
                        }, RouteHop {
                                pubkey: nodes[3].node.get_our_node_id(),
                                node_features: nodes[3].node.node_features(),
                                short_channel_id: chan_4_scid,
                                channel_features: nodes[3].node.channel_features(),
                                fee_msat: amt_msat - amt_msat / 1000,
                                cltv_expiry_delta: 100,
                        }], blinded_tail: None }
                ],
                payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), TEST_FINAL_CLTV)),
        };
        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));

        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(0xdeadbeef)).unwrap();
        check_added_monitors!(nodes[0], 2);
        let mut send_msg_events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(send_msg_events.len(), 2);
        send_msg_events.retain(|msg|
                if let MessageSendEvent::UpdateHTLCs { node_id, .. } = msg {
                        // Drop the commitment update for nodes[2], we can just let that one sit pending
                        // forever.
                        *node_id == nodes[1].node.get_our_node_id()
                } else { panic!(); }
        );

        // from here on out, the retry `RouteParameters` amount will be amt/1000
        route_params.final_value_msat /= 1000;
        route.paths.pop();

        let end_time = Instant::now() + Duration::from_secs(1);
        macro_rules! thread_body { () => { {
                // We really want std::thread::scope, but its not stable until 1.63. Until then, we get unsafe.
                let node_ref = NodePtr::from_node(&nodes[0]);
                move || {
                        let node_a = unsafe { &*node_ref.0 };
                        while Instant::now() < end_time {
                                node_a.node.get_and_clear_pending_events(); // wipe the PendingHTLCsForwardable
                                // Ignore if we have any pending events, just always pretend we just got a
                                // PendingHTLCsForwardable
                                node_a.node.process_pending_htlc_forwards();
                        }
                }
        } } }
        let mut threads = Vec::new();
        for _ in 0..16 { threads.push(std::thread::spawn(thread_body!())); }

        // Back in the main thread, poll pending messages and make sure that we never have more than
        // one HTLC pending at a time. Note that the commitment_signed_dance will fail horribly if
        // there are HTLC messages shoved in while its running. This allows us to test that we never
        // generate an additional update_add_htlc until we've fully failed the first.
        let mut previously_failed_channels = Vec::new();
        loop {
                assert_eq!(send_msg_events.len(), 1);
                let send_event = SendEvent::from_event(send_msg_events.pop().unwrap());
                assert_eq!(send_event.msgs.len(), 1);

                nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &send_event.msgs[0]);
                commitment_signed_dance!(nodes[1], nodes[0], send_event.commitment_msg, false, true);

                // Note that we only push one route into `expect_find_route` at a time, because that's all
                // the retries (should) need. If the bug is reintroduced "real" routes may be selected, but
                // we should still ultimately fail for the same reason - because we're trying to send too
                // many HTLCs at once.
                let mut new_route_params = route_params.clone();
                previously_failed_channels.push(route.paths[0].hops[1].short_channel_id);
                new_route_params.payment_params.previously_failed_channels = previously_failed_channels.clone();
                route.paths[0].hops[1].short_channel_id += 1;
                nodes[0].router.expect_find_route(new_route_params, Ok(route.clone()));

                let bs_fail_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
                nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_updates.update_fail_htlcs[0]);
                // The "normal" commitment_signed_dance delivers the final RAA and then calls
                // `check_added_monitors` to ensure only the one RAA-generated monitor update was created.
                // This races with our other threads which may generate an add-HTLCs commitment update via
                // `process_pending_htlc_forwards`. Instead, we defer the monitor update check until after
                // *we've* called `process_pending_htlc_forwards` when its guaranteed to have two updates.
                let last_raa = commitment_signed_dance!(nodes[0], nodes[1], bs_fail_updates.commitment_signed, false, true, false, true);
                nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &last_raa);

                let cur_time = Instant::now();
                if cur_time > end_time {
                        for thread in threads.drain(..) { thread.join().unwrap(); }
                }

                // Make sure we have some events to handle when we go around...
                nodes[0].node.get_and_clear_pending_events(); // wipe the PendingHTLCsForwardable
                nodes[0].node.process_pending_htlc_forwards();
                send_msg_events = nodes[0].node.get_and_clear_pending_msg_events();
                check_added_monitors!(nodes[0], 2);

                if cur_time > end_time {
                        break;
                }
        }
}

fn do_no_missing_sent_on_midpoint_reload(persist_manager_with_payment: bool) {
        // Test that if we reload in the middle of an HTLC claim commitment signed dance we'll still
        // receive the PaymentSent event even if the ChannelManager had no idea about the payment when
        // it was last persisted.
        let chanmon_cfgs = create_chanmon_cfgs(2);
        let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
        let (persister_a, persister_b, persister_c);
        let (chain_monitor_a, chain_monitor_b, chain_monitor_c);
        let (nodes_0_deserialized, nodes_0_deserialized_b, nodes_0_deserialized_c);
        let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs);

        let chan_id = create_announced_chan_between_nodes(&nodes, 0, 1).2;

        let mut nodes_0_serialized = Vec::new();
        if !persist_manager_with_payment {
                nodes_0_serialized = nodes[0].node.encode();
        }

        let (our_payment_preimage, our_payment_hash, _) = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);

        if persist_manager_with_payment {
                nodes_0_serialized = nodes[0].node.encode();
        }

        nodes[1].node.claim_funds(our_payment_preimage);
        check_added_monitors!(nodes[1], 1);
        expect_payment_claimed!(nodes[1], our_payment_hash, 1_000_000);

        let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
        nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &updates.commitment_signed);
        check_added_monitors!(nodes[0], 1);

        // The ChannelMonitor should always be the latest version, as we're required to persist it
        // during the commitment signed handling.
        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        reload_node!(nodes[0], test_default_channel_config(), &nodes_0_serialized, &[&chan_0_monitor_serialized], persister_a, chain_monitor_a, nodes_0_deserialized);

        let events = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(events.len(), 2);
        if let Event::ChannelClosed { reason: ClosureReason::OutdatedChannelManager, .. } = events[0] {} else { panic!(); }
        if let Event::PaymentSent { payment_preimage, .. } = events[1] { assert_eq!(payment_preimage, our_payment_preimage); } else { panic!(); }
        // Note that we don't get a PaymentPathSuccessful here as we leave the HTLC pending to avoid
        // the double-claim that would otherwise appear at the end of this test.
        nodes[0].node.timer_tick_occurred();
        let as_broadcasted_txn = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
        assert_eq!(as_broadcasted_txn.len(), 1);

        // Ensure that, even after some time, if we restart we still include *something* in the current
        // `ChannelManager` which prevents a `PaymentFailed` when we restart even if pending resolved
        // payments have since been timed out thanks to `IDEMPOTENCY_TIMEOUT_TICKS`.
        // A naive implementation of the fix here would wipe the pending payments set, causing a
        // failure event when we restart.
        for _ in 0..(IDEMPOTENCY_TIMEOUT_TICKS * 2) { nodes[0].node.timer_tick_occurred(); }

        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        reload_node!(nodes[0], test_default_channel_config(), &nodes[0].node.encode(), &[&chan_0_monitor_serialized], persister_b, chain_monitor_b, nodes_0_deserialized_b);
        let events = nodes[0].node.get_and_clear_pending_events();
        assert!(events.is_empty());

        // Ensure that we don't generate any further events even after the channel-closing commitment
        // transaction is confirmed on-chain.
        confirm_transaction(&nodes[0], &as_broadcasted_txn[0]);
        for _ in 0..(IDEMPOTENCY_TIMEOUT_TICKS * 2) { nodes[0].node.timer_tick_occurred(); }

        let events = nodes[0].node.get_and_clear_pending_events();
        assert!(events.is_empty());

        let chan_0_monitor_serialized = get_monitor!(nodes[0], chan_id).encode();
        reload_node!(nodes[0], test_default_channel_config(), &nodes[0].node.encode(), &[&chan_0_monitor_serialized], persister_c, chain_monitor_c, nodes_0_deserialized_c);
        let events = nodes[0].node.get_and_clear_pending_events();
        assert!(events.is_empty());
        check_added_monitors(&nodes[0], 1);
}

#[test]
fn no_missing_sent_on_midpoint_reload() {
        do_no_missing_sent_on_midpoint_reload(false);
        do_no_missing_sent_on_midpoint_reload(true);
}

fn do_claim_from_closed_chan(fail_payment: bool) {
        // Previously, LDK would refuse to claim a payment if a channel on which the payment was
        // received had been closed between when the HTLC was received and when we went to claim it.
        // This makes sense in the payment case - why pay an on-chain fee to claim the HTLC when
        // presumably the sender may retry later. Long ago it also reduced total code in the claim
        // pipeline.
        //
        // However, this doesn't make sense if you're trying to do an atomic swap or some other
        // protocol that requires atomicity with some other action - if your money got claimed
        // elsewhere you need to be able to claim the HTLC in lightning no matter what. Further, this
        // is an over-optimization - there should be a very, very low likelihood that a channel closes
        // between when we receive the last HTLC for a payment and the user goes to claim the payment.
        // Since we now have code to handle this anyway we should allow it.

        // Build 4 nodes and send an MPP payment across two paths. By building a route manually set the
        // CLTVs on the paths to different value resulting in a different claim deadline.
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
        let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes(&nodes, 0, 1);
        create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
        let chan_bd = create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 1_000_000, 0).2;
        create_announced_chan_between_nodes(&nodes, 2, 3);

        let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[3]);
        let mut route_params = RouteParameters {
                payment_params: PaymentParameters::from_node_id(nodes[3].node.get_our_node_id(), TEST_FINAL_CLTV)
                        .with_bolt11_features(nodes[1].node.invoice_features()).unwrap(),
                final_value_msat: 10_000_000,
        };
        let mut route = nodes[0].router.find_route(&nodes[0].node.get_our_node_id(), &route_params,
                None, nodes[0].node.compute_inflight_htlcs()).unwrap();
        // Make sure the route is ordered as the B->D path before C->D
        route.paths.sort_by(|a, _| if a.hops[0].pubkey == nodes[1].node.get_our_node_id() {
                std::cmp::Ordering::Less } else { std::cmp::Ordering::Greater });

        // Note that we add an extra 1 in the send pipeline to compensate for any blocks found while
        // the HTLC is being relayed.
        route.paths[0].hops[1].cltv_expiry_delta = TEST_FINAL_CLTV + 8;
        route.paths[1].hops[1].cltv_expiry_delta = TEST_FINAL_CLTV + 12;
        let final_cltv = nodes[0].best_block_info().1 + TEST_FINAL_CLTV + 8 + 1;

        nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields::secret_only(payment_secret),
                PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(1)).unwrap();
        check_added_monitors(&nodes[0], 2);
        let mut send_msgs = nodes[0].node.get_and_clear_pending_msg_events();
        send_msgs.sort_by(|a, _| {
                let a_node_id =
                        if let MessageSendEvent::UpdateHTLCs { node_id, .. } = a { node_id } else { panic!() };
                let node_b_id = nodes[1].node.get_our_node_id();
                if *a_node_id == node_b_id { std::cmp::Ordering::Less } else { std::cmp::Ordering::Greater }
        });

        assert_eq!(send_msgs.len(), 2);
        pass_along_path(&nodes[0], &[&nodes[1], &nodes[3]], 10_000_000,
                payment_hash, Some(payment_secret), send_msgs.remove(0), false, None);
        let receive_event = pass_along_path(&nodes[0], &[&nodes[2], &nodes[3]], 10_000_000,
                payment_hash, Some(payment_secret), send_msgs.remove(0), true, None);

        match receive_event.unwrap() {
                Event::PaymentClaimable { claim_deadline, .. } => {
                        assert_eq!(claim_deadline.unwrap(), final_cltv - HTLC_FAIL_BACK_BUFFER);
                },
                _ => panic!(),
        }

        // Ensure that the claim_deadline is correct, with the payment failing at exactly the given
        // height.
        connect_blocks(&nodes[3], final_cltv - HTLC_FAIL_BACK_BUFFER - nodes[3].best_block_info().1
                - if fail_payment { 0 } else { 2 });
        if fail_payment {
                // We fail the HTLC on the A->B->D path first as it expires 4 blocks earlier. We go ahead
                // and expire both immediately, though, by connecting another 4 blocks.
                let reason = HTLCDestination::FailedPayment { payment_hash };
                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[3], [reason.clone()]);
                connect_blocks(&nodes[3], 4);
                expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[3], [reason]);
                pass_failed_payment_back(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_hash, PaymentFailureReason::RecipientRejected);
        } else {
                nodes[1].node.force_close_broadcasting_latest_txn(&chan_bd, &nodes[3].node.get_our_node_id()).unwrap();
                check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false);
                check_closed_broadcast(&nodes[1], 1, true);
                let bs_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                assert_eq!(bs_tx.len(), 1);

                mine_transaction(&nodes[3], &bs_tx[0]);
                check_added_monitors(&nodes[3], 1);
                check_closed_broadcast(&nodes[3], 1, true);
                check_closed_event(&nodes[3], 1, ClosureReason::CommitmentTxConfirmed, false);

                nodes[3].node.claim_funds(payment_preimage);
                check_added_monitors(&nodes[3], 2);
                expect_payment_claimed!(nodes[3], payment_hash, 10_000_000);

                let ds_tx = nodes[3].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0);
                assert_eq!(ds_tx.len(), 1);
                check_spends!(&ds_tx[0], &bs_tx[0]);

                mine_transactions(&nodes[1], &[&bs_tx[0], &ds_tx[0]]);
                check_added_monitors(&nodes[1], 1);
                expect_payment_forwarded!(nodes[1], nodes[0], nodes[3], Some(1000), false, true);

                let bs_claims = nodes[1].node.get_and_clear_pending_msg_events();
                check_added_monitors(&nodes[1], 1);
                assert_eq!(bs_claims.len(), 1);
                if let MessageSendEvent::UpdateHTLCs { updates, .. } = &bs_claims[0] {
                        nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
                        commitment_signed_dance!(nodes[0], nodes[1], updates.commitment_signed, false, true);
                } else { panic!(); }

                expect_payment_sent!(nodes[0], payment_preimage);

                let ds_claim_msgs = nodes[3].node.get_and_clear_pending_msg_events();
                assert_eq!(ds_claim_msgs.len(), 1);
                let cs_claim_msgs = if let MessageSendEvent::UpdateHTLCs { updates, .. } = &ds_claim_msgs[0] {
                        nodes[2].node.handle_update_fulfill_htlc(&nodes[3].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
                        let cs_claim_msgs = nodes[2].node.get_and_clear_pending_msg_events();
                        check_added_monitors(&nodes[2], 1);
                        commitment_signed_dance!(nodes[2], nodes[3], updates.commitment_signed, false, true);
                        expect_payment_forwarded!(nodes[2], nodes[0], nodes[3], Some(1000), false, false);
                        cs_claim_msgs
                } else { panic!(); };

                assert_eq!(cs_claim_msgs.len(), 1);
                if let MessageSendEvent::UpdateHTLCs { updates, .. } = &cs_claim_msgs[0] {
                        nodes[0].node.handle_update_fulfill_htlc(&nodes[2].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
                        commitment_signed_dance!(nodes[0], nodes[2], updates.commitment_signed, false, true);
                } else { panic!(); }

                expect_payment_path_successful!(nodes[0]);
        }
}

#[test]
fn claim_from_closed_chan() {
        do_claim_from_closed_chan(true);
        do_claim_from_closed_chan(false);
}

fn do_test_payment_metadata_consistency(do_reload: bool, do_modify: bool) {
        // Check that a payment metadata received on one HTLC that doesn't match the one received on
        // another results in the HTLC being rejected.
        //
        // We first set up a diamond shaped network, allowing us to split a payment into two HTLCs, the
        // first of which we'll deliver and the second of which we'll fail and then re-send with
        // modified payment metadata, which will in turn result in it being failed by the recipient.
        let chanmon_cfgs = create_chanmon_cfgs(4);
        let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
        let mut config = test_default_channel_config();
        config.channel_handshake_config.max_inbound_htlc_value_in_flight_percent_of_channel = 50;
        let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, Some(config), Some(config), Some(config)]);

        let persister;
        let new_chain_monitor;
        let nodes_0_deserialized;

        let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);

        create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
        let chan_id_bd = create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 1_000_000, 0).2;
        create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
        let chan_id_cd = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 1_000_000, 0).2;

        // Pay more than half of each channel's max, requiring MPP
        let amt_msat = 750_000_000;
        let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[3], Some(amt_msat));
        let payment_id = PaymentId(payment_hash.0);
        let payment_metadata = vec![44, 49, 52, 142];

        let payment_params = PaymentParameters::from_node_id(nodes[3].node.get_our_node_id(), TEST_FINAL_CLTV)
                .with_bolt11_features(nodes[1].node.invoice_features()).unwrap();
        let mut route_params = RouteParameters {
                payment_params,
                final_value_msat: amt_msat,
        };

        // Send the MPP payment, delivering the updated commitment state to nodes[1].
        nodes[0].node.send_payment(payment_hash, RecipientOnionFields {
                        payment_secret: Some(payment_secret), payment_metadata: Some(payment_metadata),
                }, payment_id, route_params.clone(), Retry::Attempts(1)).unwrap();
        check_added_monitors!(nodes[0], 2);

        let mut send_events = nodes[0].node.get_and_clear_pending_msg_events();
        assert_eq!(send_events.len(), 2);
        let first_send = SendEvent::from_event(send_events.pop().unwrap());
        let second_send = SendEvent::from_event(send_events.pop().unwrap());

        let (b_recv_ev, c_recv_ev) = if first_send.node_id == nodes[1].node.get_our_node_id() {
                (&first_send, &second_send)
        } else {
                (&second_send, &first_send)
        };
        nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &b_recv_ev.msgs[0]);
        commitment_signed_dance!(nodes[1], nodes[0], b_recv_ev.commitment_msg, false, true);

        expect_pending_htlcs_forwardable!(nodes[1]);
        check_added_monitors(&nodes[1], 1);
        let b_forward_ev = SendEvent::from_node(&nodes[1]);
        nodes[3].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &b_forward_ev.msgs[0]);
        commitment_signed_dance!(nodes[3], nodes[1], b_forward_ev.commitment_msg, false, true);

        expect_pending_htlcs_forwardable!(nodes[3]);

        // Before delivering the second MPP HTLC to nodes[2], disconnect nodes[2] and nodes[3], which
        // will result in nodes[2] failing the HTLC back.
        nodes[2].node.peer_disconnected(&nodes[3].node.get_our_node_id());
        nodes[3].node.peer_disconnected(&nodes[2].node.get_our_node_id());

        nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &c_recv_ev.msgs[0]);
        commitment_signed_dance!(nodes[2], nodes[0], c_recv_ev.commitment_msg, false, true);

        let cs_fail = get_htlc_update_msgs(&nodes[2], &nodes[0].node.get_our_node_id());
        nodes[0].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &cs_fail.update_fail_htlcs[0]);
        commitment_signed_dance!(nodes[0], nodes[2], cs_fail.commitment_signed, false, true);

        let payment_fail_retryable_evs = nodes[0].node.get_and_clear_pending_events();
        assert_eq!(payment_fail_retryable_evs.len(), 2);
        if let Event::PaymentPathFailed { .. } = payment_fail_retryable_evs[0] {} else { panic!(); }
        if let Event::PendingHTLCsForwardable { .. } = payment_fail_retryable_evs[1] {} else { panic!(); }

        // Before we allow the HTLC to be retried, optionally change the payment_metadata we have
        // stored for our payment.
        if do_modify {
                nodes[0].node.test_set_payment_metadata(payment_id, Some(Vec::new()));
        }

        // Optionally reload nodes[3] to check that the payment_metadata is properly serialized with
        // the payment state.
        if do_reload {
                let mon_bd = get_monitor!(nodes[3], chan_id_bd).encode();
                let mon_cd = get_monitor!(nodes[3], chan_id_cd).encode();
                reload_node!(nodes[3], config, &nodes[3].node.encode(), &[&mon_bd, &mon_cd],
                        persister, new_chain_monitor, nodes_0_deserialized);
                nodes[1].node.peer_disconnected(&nodes[3].node.get_our_node_id());
                reconnect_nodes(ReconnectArgs::new(&nodes[1], &nodes[3]));
        }
        let mut reconnect_args = ReconnectArgs::new(&nodes[2], &nodes[3]);
        reconnect_args.send_channel_ready = (true, true);
        reconnect_nodes(reconnect_args);

        // Create a new channel between C and D as A will refuse to retry on the existing one because
        // it just failed.
        let chan_id_cd_2 = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 1_000_000, 0).2;

        // Now retry the failed HTLC.
        nodes[0].node.process_pending_htlc_forwards();
        check_added_monitors(&nodes[0], 1);
        let as_resend = SendEvent::from_node(&nodes[0]);
        nodes[2].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &as_resend.msgs[0]);
        commitment_signed_dance!(nodes[2], nodes[0], as_resend.commitment_msg, false, true);

        expect_pending_htlcs_forwardable!(nodes[2]);
        check_added_monitors(&nodes[2], 1);
        let cs_forward = SendEvent::from_node(&nodes[2]);
        nodes[3].node.handle_update_add_htlc(&nodes[2].node.get_our_node_id(), &cs_forward.msgs[0]);
        commitment_signed_dance!(nodes[3], nodes[2], cs_forward.commitment_msg, false, true);

        // Finally, check that nodes[3] does the correct thing - either accepting the payment or, if
        // the payment metadata was modified, failing only the one modified HTLC and retaining the
        // other.
        if do_modify {
                expect_pending_htlcs_forwardable_ignore!(nodes[3]);
                nodes[3].node.process_pending_htlc_forwards();
                expect_pending_htlcs_forwardable_conditions(nodes[3].node.get_and_clear_pending_events(),
                        &[HTLCDestination::FailedPayment {payment_hash}]);
                nodes[3].node.process_pending_htlc_forwards();

                check_added_monitors(&nodes[3], 1);
                let ds_fail = get_htlc_update_msgs(&nodes[3], &nodes[2].node.get_our_node_id());

                nodes[2].node.handle_update_fail_htlc(&nodes[3].node.get_our_node_id(), &ds_fail.update_fail_htlcs[0]);
                commitment_signed_dance!(nodes[2], nodes[3], ds_fail.commitment_signed, false, true);
                expect_pending_htlcs_forwardable_conditions(nodes[2].node.get_and_clear_pending_events(),
                        &[HTLCDestination::NextHopChannel { node_id: Some(nodes[3].node.get_our_node_id()), channel_id: chan_id_cd_2 }]);
        } else {
                expect_pending_htlcs_forwardable!(nodes[3]);
                expect_payment_claimable!(nodes[3], payment_hash, payment_secret, amt_msat);
                claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]], false, payment_preimage);
        }
}

#[test]
fn test_payment_metadata_consistency() {
        do_test_payment_metadata_consistency(true, true);
        do_test_payment_metadata_consistency(true, false);
        do_test_payment_metadata_consistency(false, true);
        do_test_payment_metadata_consistency(false, false);
}