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Merged
valentinewallace merged 3 commits into from
Feb 6, 2026
+193 −66
Merged

Hold in-flight monitor updates until background event processing #4377

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60b5d66
Make get_latest_mon_update_id a helper on TestChainMonitor
wpaulino Feb 6, 2026
7e84268
Hold in-flight monitor updates until background event processing
wpaulino Feb 4, 2026
f128b85
Rustfmt ChannelManager::process_background_events
wpaulino Feb 5, 2026
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71 changes: 32 additions & 39 deletions lightning/src/ln/chanmon_update_fail_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -49,13 +49,6 @@ use crate::prelude::*;
use crate::sync::{Arc, Mutex};
use bitcoin::hashes::Hash;

fn get_latest_mon_update_id<'a, 'b, 'c>(
node: &Node<'a, 'b, 'c>, channel_id: ChannelId,
) -> (u64, u64) {
let monitor_id_state = node.chain_monitor.latest_monitor_update_id.lock().unwrap();
monitor_id_state.get(&channel_id).unwrap().clone()
}

#[test]
fn test_monitor_and_persister_update_fail() {
// Test that if both updating the `ChannelMonitor` and persisting the updated
Expand Down Expand Up @@ -212,7 +205,7 @@ fn do_test_simple_monitor_temporary_update_fail(disconnect: bool) {
}

chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[0], 0);

Expand Down Expand Up @@ -404,7 +397,7 @@ fn do_test_monitor_temporary_update_fail(disconnect_count: usize) {

// Now fix monitor updating...
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[0], 0);

Expand Down Expand Up @@ -757,7 +750,7 @@ fn test_monitor_update_fail_cs() {
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[1], 0);
let responses = nodes[1].node.get_and_clear_pending_msg_events();
Expand Down Expand Up @@ -792,7 +785,7 @@ fn test_monitor_update_fail_cs() {
}

chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[0], 0);

Expand Down Expand Up @@ -868,7 +861,7 @@ fn test_monitor_update_fail_no_rebroadcast() {
check_added_monitors(&nodes[1], 1);

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
check_added_monitors(&nodes[1], 0);
Expand Down Expand Up @@ -938,7 +931,7 @@ fn test_monitor_update_raa_while_paused() {
assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());
check_added_monitors(&nodes[0], 1);

let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[0], 0);

Expand Down Expand Up @@ -1080,7 +1073,7 @@ fn do_test_monitor_update_fail_raa(test_ignore_second_cs: bool) {
// Restore monitor updating, ensuring we immediately get a fail-back update and a
// update_add update.
chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], chan_2.2);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_2.2);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_2.2, latest_update);
check_added_monitors(&nodes[1], 0);
expect_and_process_pending_htlcs_and_htlc_handling_failed(
Expand Down Expand Up @@ -1354,7 +1347,7 @@ fn test_monitor_update_fail_reestablish() {
assert_eq!(bs_channel_upd.contents.channel_flags & 2, 0);

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], chan_1.2);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_1.2);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_1.2, latest_update);
check_added_monitors(&nodes[1], 0);

Expand Down Expand Up @@ -1439,7 +1432,7 @@ fn raa_no_response_awaiting_raa_state() {
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
check_added_monitors(&nodes[1], 1);

let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
// nodes[1] should be AwaitingRAA here!
check_added_monitors(&nodes[1], 0);
Expand Down Expand Up @@ -1568,7 +1561,7 @@ fn claim_while_disconnected_monitor_update_fail() {
// Now un-fail the monitor, which will result in B sending its original commitment update,
// receiving the commitment update from A, and the resulting commitment dances.
chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[1], 0);

Expand Down Expand Up @@ -1697,7 +1690,7 @@ fn monitor_failed_no_reestablish_response() {
get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, node_b_id);

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[1], 0);
let bs_responses = get_revoke_commit_msgs(&nodes[1], &node_a_id);
Expand Down Expand Up @@ -1795,7 +1788,7 @@ fn first_message_on_recv_ordering() {
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[1], 0);

Expand Down Expand Up @@ -1894,7 +1887,7 @@ fn test_monitor_update_fail_claim() {

// Now restore monitor updating on the 0<->1 channel and claim the funds on B.
let channel_id = chan_1.2;
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
expect_payment_claimed!(nodes[1], payment_hash_1, 1_000_000);
check_added_monitors(&nodes[1], 0);
Expand Down Expand Up @@ -2023,7 +2016,7 @@ fn test_monitor_update_on_pending_forwards() {
check_added_monitors(&nodes[1], 1);

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], chan_1.2);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_1.2);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_1.2, latest_update);
check_added_monitors(&nodes[1], 0);

Expand Down Expand Up @@ -2094,7 +2087,7 @@ fn monitor_update_claim_fail_no_response() {
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
expect_payment_claimed!(nodes[1], payment_hash_1, 1_000_000);
check_added_monitors(&nodes[1], 0);
Expand Down Expand Up @@ -2166,7 +2159,7 @@ fn do_during_funding_monitor_fail(
assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty());
assert!(nodes[0].node.get_and_clear_pending_events().is_empty());
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[0], 0);
expect_channel_pending_event(&nodes[0], &node_b_id);
Expand Down Expand Up @@ -2221,7 +2214,7 @@ fn do_during_funding_monitor_fail(
}

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
check_added_monitors(&nodes[1], 0);

Expand Down Expand Up @@ -2339,7 +2332,7 @@ fn test_path_paused_mpp() {

// And check that, after we successfully update the monitor for chan_2 we can pass the second
// HTLC along to nodes[3] and claim the whole payment back to nodes[0].
let (latest_update, _) = get_latest_mon_update_id(&nodes[0], chan_2_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(chan_2_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_2_id, latest_update);

let mut events = nodes[0].node.get_and_clear_pending_msg_events();
Expand Down Expand Up @@ -2787,7 +2780,7 @@ fn do_channel_holding_cell_serialize(disconnect: bool, reload_a: bool) {
// If we finish updating the monitor, we should free the holding cell right away (this did
// not occur prior to #756). This should result in a new monitor update.
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (mon_id, _) = get_latest_mon_update_id(&nodes[0], chan_id);
let (mon_id, _) = nodes[0].chain_monitor.get_latest_mon_update_id(chan_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_id, mon_id);
expect_payment_claimed!(nodes[0], payment_hash_0, 100_000);
check_added_monitors(&nodes[0], 1);
Expand Down Expand Up @@ -3039,7 +3032,7 @@ fn test_temporary_error_during_shutdown() {
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);

let (latest_update, _) = get_latest_mon_update_id(&nodes[0], channel_id);
let (latest_update, _) = nodes[0].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[0].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);
nodes[1].node.handle_closing_signed(
node_a_id,
Expand All @@ -3049,7 +3042,7 @@ fn test_temporary_error_during_shutdown() {
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update);

nodes[0].node.handle_closing_signed(
Expand Down Expand Up @@ -3095,7 +3088,7 @@ fn double_temp_error() {
// `claim_funds` results in a ChannelMonitorUpdate.
nodes[1].node.claim_funds(payment_preimage_1);
check_added_monitors(&nodes[1], 1);
let (latest_update_1, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update_1, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);

chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
// Previously, this would've panicked due to a double-call to `Channel::monitor_update_failed`,
Expand All @@ -3104,7 +3097,7 @@ fn double_temp_error() {
check_added_monitors(&nodes[1], 1);
chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);

let (latest_update_2, _) = get_latest_mon_update_id(&nodes[1], channel_id);
let (latest_update_2, _) = nodes[1].chain_monitor.get_latest_mon_update_id(channel_id);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(channel_id, latest_update_1);
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
check_added_monitors(&nodes[1], 0);
Expand Down Expand Up @@ -3511,7 +3504,7 @@ fn do_test_blocked_chan_preimage_release(completion_mode: BlockedUpdateComplMode
reconnect_nodes(a_b_reconnect);
reconnect_nodes(ReconnectArgs::new(&nodes[2], &nodes[1]));
} else if completion_mode == BlockedUpdateComplMode::Async {
let (latest_update, _) = get_latest_mon_update_id(&nodes[1], chan_id_2);
let (latest_update, _) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_2);
nodes[1]
.chain_monitor
.chain_monitor
Expand Down Expand Up @@ -3689,7 +3682,7 @@ fn do_test_inverted_mon_completion_order(
// (Finally) complete the A <-> B ChannelMonitorUpdate, ensuring the preimage is durably on
// disk in the proper ChannelMonitor, unblocking the B <-> C ChannelMonitor updating
// process.
let (_, ab_update_id) = get_latest_mon_update_id(&nodes[1], chan_id_ab);
let (_, ab_update_id) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_ab);
nodes[1]
.chain_monitor
.chain_monitor
Expand Down Expand Up @@ -3722,7 +3715,7 @@ fn do_test_inverted_mon_completion_order(
// ChannelMonitorUpdate hasn't yet completed.
reconnect_nodes(ReconnectArgs::new(&nodes[0], &nodes[1]));

let (_, ab_update_id) = get_latest_mon_update_id(&nodes[1], chan_id_ab);
let (_, ab_update_id) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_ab);
nodes[1]
.chain_monitor
.chain_monitor
Expand Down Expand Up @@ -3935,7 +3928,7 @@ fn do_test_durable_preimages_on_closed_channel(

// Once the blocked `ChannelMonitorUpdate` *finally* completes, the pending
// `PaymentForwarded` event will finally be released.
let (_, ab_update_id) = get_latest_mon_update_id(&nodes[1], chan_id_ab);
let (_, ab_update_id) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_ab);
nodes[1].chain_monitor.chain_monitor.force_channel_monitor_updated(chan_id_ab, ab_update_id);

// If the A<->B channel was closed before we reload, we'll replay the claim against it on
Expand Down Expand Up @@ -4047,7 +4040,7 @@ fn do_test_reload_mon_update_completion_actions(close_during_reload: bool) {
mine_transaction_without_consistency_checks(&nodes[1], &as_closing_tx[0]);
}

let (_, bc_update_id) = get_latest_mon_update_id(&nodes[1], chan_id_bc);
let (_, bc_update_id) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_bc);
let mut events = nodes[1].node.get_and_clear_pending_events();
assert_eq!(events.len(), if close_during_reload { 2 } else { 1 });
expect_payment_forwarded(
Expand All @@ -4072,7 +4065,7 @@ fn do_test_reload_mon_update_completion_actions(close_during_reload: bool) {
// Once we run event processing the monitor should free, check that it was indeed the B<->C
// channel which was updated.
check_added_monitors(&nodes[1], if close_during_reload { 2 } else { 1 });
let (_, post_ev_bc_update_id) = get_latest_mon_update_id(&nodes[1], chan_id_bc);
let (_, post_ev_bc_update_id) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_bc);
assert!(bc_update_id != post_ev_bc_update_id);

// Finally, check that there's nothing left to do on B<->C reconnect and the channel operates
Expand Down Expand Up @@ -4162,7 +4155,7 @@ fn do_test_glacial_peer_cant_hang(hold_chan_a: bool) {

// ...but once we complete the A<->B channel preimage persistence, the B<->C channel
// unlocks and we send both peers commitment updates.
let (ab_update_id, _) = get_latest_mon_update_id(&nodes[1], chan_id_ab);
let (ab_update_id, _) = nodes[1].chain_monitor.get_latest_mon_update_id(chan_id_ab);
assert!(nodes[1]
.chain_monitor
.chain_monitor
Expand Down Expand Up @@ -5122,7 +5115,7 @@ fn test_mpp_claim_to_holding_cell() {
check_added_monitors(&nodes[3], 2);

// Complete the B <-> D monitor update, freeing the first fulfill.
let (latest_id, _) = get_latest_mon_update_id(&nodes[3], chan_3_id);
let (latest_id, _) = nodes[3].chain_monitor.get_latest_mon_update_id(chan_3_id);
nodes[3].chain_monitor.chain_monitor.channel_monitor_updated(chan_3_id, latest_id).unwrap();
let mut b_claim = get_htlc_update_msgs(&nodes[3], &node_b_id);

Expand All @@ -5133,7 +5126,7 @@ fn test_mpp_claim_to_holding_cell() {

// Finally, complete the C <-> D monitor update. Previously, this unlock failed to be processed
// due to the existence of the blocked RAA update above.
let (latest_id, _) = get_latest_mon_update_id(&nodes[3], chan_4_id);
let (latest_id, _) = nodes[3].chain_monitor.get_latest_mon_update_id(chan_4_id);
nodes[3].chain_monitor.chain_monitor.channel_monitor_updated(chan_4_id, latest_id).unwrap();
// Once we process monitor events (in this case by checking for the `PaymentClaimed` event, the
// RAA monitor update blocked above will be released.
Expand Down
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