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Add FundingNeeded event for splicing #4290

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f3eb94e
FIXME: Why does handle_channel_close override the witness?
jkczyz Jan 14, 2026
b5a1835
Move FundingTxInput::sequence to Utxo
jkczyz Jan 13, 2026
8f82573
Use FundingTxInput instead of Utxo in CoinSelection
jkczyz Jan 14, 2026
8530bbd
Add FundingNeeded event for splicing
jkczyz Dec 18, 2025
5e4096c
f - fix chanmon_consistency
jkczyz Jan 21, 2026
fcccbac
Use CoinSelection::change_output when splicing
jkczyz Jan 20, 2026
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161 changes: 47 additions & 114 deletions fuzz/src/chanmon_consistency.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
//! send-side handling is correct, other peers. We consider it a failure if any action results in a
//! channel being force-closed.

use bitcoin::FeeRate;
use bitcoin::amount::Amount;
use bitcoin::constants::genesis_block;
use bitcoin::locktime::absolute::LockTime;
Expand All @@ -43,6 +44,7 @@ use lightning::chain::{
chainmonitor, channelmonitor, BestBlock, ChannelMonitorUpdateStatus, Confirm, Watch,
};
use lightning::events;
use lightning::events::bump_transaction::sync::{WalletSourceSync, WalletSync};
use lightning::ln::channel::{
FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE, MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS,
};
Expand All @@ -52,7 +54,7 @@ use lightning::ln::channelmanager::{
RecipientOnionFields,
};
use lightning::ln::functional_test_utils::*;
use lightning::ln::funding::{FundingTxInput, SpliceContribution};
use lightning::ln::funding::SpliceContribution;
use lightning::ln::inbound_payment::ExpandedKey;
use lightning::ln::msgs::{
BaseMessageHandler, ChannelMessageHandler, CommitmentUpdate, Init, MessageSendEvent,
Expand All @@ -70,12 +72,14 @@ use lightning::sign::{
SignerProvider,
};
use lightning::types::payment::{PaymentHash, PaymentPreimage, PaymentSecret};
use lightning::util::async_poll::{MaybeSend, MaybeSync};
use lightning::util::config::UserConfig;
use lightning::util::errors::APIError;
use lightning::util::hash_tables::*;
use lightning::util::logger::Logger;
use lightning::util::ser::{LengthReadable, ReadableArgs, Writeable, Writer};
use lightning::util::test_channel_signer::{EnforcementState, TestChannelSigner};
use lightning::util::test_utils::TestWalletSource;

use lightning_invoice::RawBolt11Invoice;

Expand Down Expand Up @@ -168,63 +172,6 @@ impl Writer for VecWriter {
}
}

pub struct TestWallet {
secret_key: SecretKey,
utxos: Mutex<Vec<lightning::events::bump_transaction::Utxo>>,
secp: Secp256k1<bitcoin::secp256k1::All>,
}

impl TestWallet {
pub fn new(secret_key: SecretKey) -> Self {
Self { secret_key, utxos: Mutex::new(Vec::new()), secp: Secp256k1::new() }
}

fn get_change_script(&self) -> Result<ScriptBuf, ()> {
let public_key = bitcoin::PublicKey::new(self.secret_key.public_key(&self.secp));
Ok(ScriptBuf::new_p2wpkh(&public_key.wpubkey_hash().unwrap()))
}

pub fn add_utxo(&self, outpoint: bitcoin::OutPoint, value: Amount) -> TxOut {
let public_key = bitcoin::PublicKey::new(self.secret_key.public_key(&self.secp));
let utxo = lightning::events::bump_transaction::Utxo::new_v0_p2wpkh(
outpoint,
value,
&public_key.wpubkey_hash().unwrap(),
);
self.utxos.lock().unwrap().push(utxo.clone());
utxo.output
}

pub fn sign_tx(
&self, mut tx: Transaction,
) -> Result<Transaction, bitcoin::sighash::P2wpkhError> {
let utxos = self.utxos.lock().unwrap();
for i in 0..tx.input.len() {
if let Some(utxo) =
utxos.iter().find(|utxo| utxo.outpoint == tx.input[i].previous_output)
{
let sighash = bitcoin::sighash::SighashCache::new(&tx).p2wpkh_signature_hash(
i,
&utxo.output.script_pubkey,
utxo.output.value,
bitcoin::EcdsaSighashType::All,
)?;
let signature = self.secp.sign_ecdsa(
&secp256k1::Message::from_digest(sighash.to_byte_array()),
&self.secret_key,
);
let bitcoin_sig = bitcoin::ecdsa::Signature {
signature,
sighash_type: bitcoin::EcdsaSighashType::All,
};
tx.input[i].witness =
bitcoin::Witness::p2wpkh(&bitcoin_sig, &self.secret_key.public_key(&self.secp));
}
}
Ok(tx)
}
}

/// The LDK API requires that any time we tell it we're done persisting a `ChannelMonitor[Update]`
/// we never pass it in as the "latest" `ChannelMonitor` on startup. However, we can pass
/// out-of-date monitors as long as we never told LDK we finished persisting them, which we do by
Expand Down Expand Up @@ -532,7 +479,7 @@ type ChanMan<'a> = ChannelManager<
Arc<FuzzEstimator>,
&'a FuzzRouter,
&'a FuzzRouter,
Arc<dyn Logger>,
Arc<dyn Logger + MaybeSend + MaybeSync>,
>;

#[inline]
Expand Down Expand Up @@ -701,14 +648,14 @@ fn send_hop_payment(
}

#[inline]
pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
pub fn do_test<Out: Output + MaybeSend + MaybeSync>(data: &[u8], underlying_out: Out, anchors: bool) {
let out = SearchingOutput::new(underlying_out);
let broadcast = Arc::new(TestBroadcaster {});
let router = FuzzRouter {};

macro_rules! make_node {
($node_id: expr, $fee_estimator: expr) => {{
let logger: Arc<dyn Logger> =
let logger: Arc<dyn Logger + MaybeSend + MaybeSync> =
Arc::new(test_logger::TestLogger::new($node_id.to_string(), out.clone()));
let node_secret = SecretKey::from_slice(&[
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
Expand Down Expand Up @@ -758,6 +705,7 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
),
monitor,
keys_manager,
logger,
)
}};
}
Expand All @@ -772,7 +720,7 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
keys,
fee_estimator| {
let keys_manager = Arc::clone(keys);
let logger: Arc<dyn Logger> =
let logger: Arc<dyn Logger + MaybeSend + MaybeSync> =
Arc::new(test_logger::TestLogger::new(node_id.to_string(), out.clone()));
let chain_monitor = Arc::new(TestChainMonitor::new(
broadcast.clone(),
Expand Down Expand Up @@ -1048,9 +996,9 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
}};
}

let wallet_a = TestWallet::new(SecretKey::from_slice(&[1; 32]).unwrap());
let wallet_b = TestWallet::new(SecretKey::from_slice(&[2; 32]).unwrap());
let wallet_c = TestWallet::new(SecretKey::from_slice(&[3; 32]).unwrap());
let wallet_a = TestWalletSource::new(SecretKey::from_slice(&[1; 32]).unwrap());
let wallet_b = TestWalletSource::new(SecretKey::from_slice(&[2; 32]).unwrap());
let wallet_c = TestWalletSource::new(SecretKey::from_slice(&[3; 32]).unwrap());
let wallets = vec![wallet_a, wallet_b, wallet_c];
let coinbase_tx = bitcoin::Transaction {
version: bitcoin::transaction::Version::TWO,
Expand All @@ -1064,12 +1012,8 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
})
.collect(),
};
let coinbase_txid = coinbase_tx.compute_txid();
wallets.iter().enumerate().for_each(|(i, w)| {
w.add_utxo(
bitcoin::OutPoint { txid: coinbase_txid, vout: i as u32 },
Amount::from_sat(100_000),
);
w.add_utxo(coinbase_tx.clone(), i as u32);
});

let fee_est_a = Arc::new(FuzzEstimator { ret_val: atomic::AtomicU32::new(253) });
Expand All @@ -1081,11 +1025,13 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {

// 3 nodes is enough to hit all the possible cases, notably unknown-source-unknown-dest
// forwarding.
let (node_a, mut monitor_a, keys_manager_a) = make_node!(0, fee_est_a);
let (node_b, mut monitor_b, keys_manager_b) = make_node!(1, fee_est_b);
let (node_c, mut monitor_c, keys_manager_c) = make_node!(2, fee_est_c);
let (node_a, mut monitor_a, keys_manager_a, logger_a) = make_node!(0, fee_est_a);
let (node_b, mut monitor_b, keys_manager_b, logger_b) = make_node!(1, fee_est_b);
let (node_c, mut monitor_c, keys_manager_c, logger_c) = make_node!(2, fee_est_c);

let mut nodes = [node_a, node_b, node_c];
let loggers = [logger_a, logger_b, logger_c];
let fee_estimators = [Arc::clone(&fee_est_a), Arc::clone(&fee_est_b), Arc::clone(&fee_est_c)];

let chan_1_id = make_channel!(nodes[0], nodes[1], keys_manager_b, 0);
let chan_2_id = make_channel!(nodes[1], nodes[2], keys_manager_c, 1);
Expand Down Expand Up @@ -1536,6 +1482,29 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
events::Event::ChannelReady { .. } => {},
events::Event::HTLCHandlingFailed { .. } => {},

events::Event::FundingNeeded {
channel_id,
counterparty_node_id,
funding_template,
..
} => {
let wallet =
WalletSync::new(&wallets[$node], Arc::clone(&loggers[$node]));
let feerate_sat_per_kw =
fee_estimators[$node].ret_val.load(atomic::Ordering::Acquire);
let feerate = FeeRate::from_sat_per_kwu(feerate_sat_per_kw as u64);
let contribution =
funding_template.build_sync(&wallet, feerate).unwrap();
let locktime = None;
nodes[$node]
.funding_contributed(
&channel_id,
&counterparty_node_id,
contribution,
locktime,
)
.unwrap();
},
events::Event::FundingTransactionReadyForSigning {
channel_id,
counterparty_node_id,
Expand Down Expand Up @@ -1859,16 +1828,11 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
},

0xa0 => {
let input = FundingTxInput::new_p2wpkh(coinbase_tx.clone(), 0).unwrap();
let contribution =
SpliceContribution::splice_in(Amount::from_sat(10_000), vec![input], None);
let funding_feerate_sat_per_kw = fee_est_a.ret_val.load(atomic::Ordering::Acquire);
let contribution = SpliceContribution::splice_in(Amount::from_sat(10_000));
if let Err(e) = nodes[0].splice_channel(
&chan_a_id,
&nodes[1].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -1878,16 +1842,11 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
}
},
0xa1 => {
let input = FundingTxInput::new_p2wpkh(coinbase_tx.clone(), 1).unwrap();
let contribution =
SpliceContribution::splice_in(Amount::from_sat(10_000), vec![input], None);
let funding_feerate_sat_per_kw = fee_est_b.ret_val.load(atomic::Ordering::Acquire);
let contribution = SpliceContribution::splice_in(Amount::from_sat(10_000));
if let Err(e) = nodes[1].splice_channel(
&chan_a_id,
&nodes[0].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -1897,16 +1856,11 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
}
},
0xa2 => {
let input = FundingTxInput::new_p2wpkh(coinbase_tx.clone(), 0).unwrap();
let contribution =
SpliceContribution::splice_in(Amount::from_sat(10_000), vec![input], None);
let funding_feerate_sat_per_kw = fee_est_b.ret_val.load(atomic::Ordering::Acquire);
let contribution = SpliceContribution::splice_in(Amount::from_sat(10_000));
if let Err(e) = nodes[1].splice_channel(
&chan_b_id,
&nodes[2].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -1916,16 +1870,11 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
}
},
0xa3 => {
let input = FundingTxInput::new_p2wpkh(coinbase_tx.clone(), 1).unwrap();
let contribution =
SpliceContribution::splice_in(Amount::from_sat(10_000), vec![input], None);
let funding_feerate_sat_per_kw = fee_est_c.ret_val.load(atomic::Ordering::Acquire);
let contribution = SpliceContribution::splice_in(Amount::from_sat(10_000));
if let Err(e) = nodes[2].splice_channel(
&chan_b_id,
&nodes[1].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -1950,14 +1899,10 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
value: Amount::from_sat(MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS),
script_pubkey: coinbase_tx.output[0].script_pubkey.clone(),
}]);
let funding_feerate_sat_per_kw =
fee_est_a.ret_val.load(atomic::Ordering::Acquire);
if let Err(e) = nodes[0].splice_channel(
&chan_a_id,
&nodes[1].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -1979,14 +1924,10 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
value: Amount::from_sat(MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS),
script_pubkey: coinbase_tx.output[1].script_pubkey.clone(),
}]);
let funding_feerate_sat_per_kw =
fee_est_b.ret_val.load(atomic::Ordering::Acquire);
if let Err(e) = nodes[1].splice_channel(
&chan_a_id,
&nodes[0].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -2008,14 +1949,10 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
value: Amount::from_sat(MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS),
script_pubkey: coinbase_tx.output[1].script_pubkey.clone(),
}]);
let funding_feerate_sat_per_kw =
fee_est_b.ret_val.load(atomic::Ordering::Acquire);
if let Err(e) = nodes[1].splice_channel(
&chan_b_id,
&nodes[2].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand All @@ -2037,14 +1974,10 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
value: Amount::from_sat(MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS),
script_pubkey: coinbase_tx.output[2].script_pubkey.clone(),
}]);
let funding_feerate_sat_per_kw =
fee_est_c.ret_val.load(atomic::Ordering::Acquire);
if let Err(e) = nodes[2].splice_channel(
&chan_b_id,
&nodes[1].get_our_node_id(),
contribution,
funding_feerate_sat_per_kw,
None,
) {
assert!(
matches!(e, APIError::APIMisuseError { ref err } if err.contains("splice pending")),
Expand Down Expand Up @@ -2276,7 +2209,7 @@ impl<O: Output> SearchingOutput<O> {
}
}

pub fn chanmon_consistency_test<Out: Output>(data: &[u8], out: Out) {
pub fn chanmon_consistency_test<Out: Output + MaybeSend + MaybeSync>(data: &[u8], out: Out) {
do_test(data, out.clone(), false);
do_test(data, out, true);
}
Expand Down
3 changes: 2 additions & 1 deletion lightning-tests/src/upgrade_downgrade_tests.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -455,7 +455,8 @@ fn do_test_0_1_htlc_forward_after_splice(fail_htlc: bool) {
value: Amount::from_sat(1_000),
script_pubkey: nodes[0].wallet_source.get_change_script().unwrap(),
}]);
let splice_tx = splice_channel(&nodes[0], &nodes[1], ChannelId(chan_id_bytes_a), contribution);
let (splice_tx, _) =
splice_channel(&nodes[0], &nodes[1], ChannelId(chan_id_bytes_a), contribution);
for node in nodes.iter() {
mine_transaction(node, &splice_tx);
connect_blocks(node, ANTI_REORG_DELAY - 1);
Expand Down
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