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Merged
merged 3 commits into from
Jul 22, 2025
Merged

#3775 follow-ups #3945

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deadccf
Use more idiomatic `sum` method when possible
tankyleo Jul 3, 2025
a954fff
Update the docs for `ClaimableOnChannelClose.transaction_fee_satoshis`
tankyleo Jul 7, 2025
3294d45
Add a debug message if we catch an inconsistency in a `TxBuilder` impl
tankyleo Jul 7, 2025
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8 changes: 5 additions & 3 deletions lightning/src/chain/channelmonitor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -774,6 +774,8 @@ pub enum Balance {
amount_satoshis: u64,
/// The transaction fee we pay for the closing commitment transaction. This amount is not
/// included in the [`Balance::ClaimableOnChannelClose::amount_satoshis`] value.
/// This amount includes the sum of dust HTLCs on the commitment transaction, any elided anchors,
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@TheBlueMatt TheBlueMatt Jul 22, 2025

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nit you might heave meant to include a newline here to create a paragraph break. when rustdocs renders it ignores line breaks unless there's a full empty line between sections of text, which creates a paragraph break. Makes the in-source docs look a little tall but the rendering isn't that bad.

/// as well as the sum of msat amounts rounded down from non-dust HTLCs.
///
/// Note that if this channel is inbound (and thus our counterparty pays the commitment
/// transaction fee) this value will be zero. For [`ChannelMonitor`]s created prior to LDK
Expand Down Expand Up @@ -2860,11 +2862,11 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
let to_self_value_sat = us.funding.current_holder_commitment_tx.to_broadcaster_value_sat();
res.push(Balance::ClaimableOnChannelClose {
amount_satoshis: to_self_value_sat + claimable_inbound_htlc_value_sat,
// In addition to `commit_tx_fee_sat`, this can also include dust HTLCs, and the total msat amount rounded down from non-dust HTLCs
// In addition to `commit_tx_fee_sat`, this can also include dust HTLCs, any elided anchors,
// and the total msat amount rounded down from non-dust HTLCs
transaction_fee_satoshis: if us.holder_pays_commitment_tx_fee.unwrap_or(true) {
let transaction = &us.funding.current_holder_commitment_tx.trust().built_transaction().transaction;
// Unwrap here; commitment transactions always have at least one output
let output_value_sat = transaction.output.iter().map(|txout| txout.value).reduce(|sum, value| sum + value).unwrap().to_sat();
let output_value_sat: u64 = transaction.output.iter().map(|txout| txout.value.to_sat()).sum();
us.funding.channel_parameters.channel_value_satoshis - output_value_sat
} else { 0 },
outbound_payment_htlc_rounded_msat,
Expand Down
37 changes: 23 additions & 14 deletions lightning/src/ln/channel.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4140,12 +4140,17 @@ where
// Channel state once they will not be present in the next received commitment
// transaction).
let (local_balance_before_fee_msat, remote_balance_before_fee_msat) = {
let mut removed_outbound_total_msat = 0;
for htlc in self.pending_outbound_htlcs.iter() {
if let OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_, _)) | OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_, _)) = htlc.state {
removed_outbound_total_msat += htlc.amount_msat;
}
}
let removed_outbound_total_msat: u64 = self.pending_outbound_htlcs
.iter()
.filter_map(|htlc| {
matches!(
htlc.state,
OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_, _))
| OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_, _))
)
.then_some(htlc.amount_msat)
})
.sum();
let pending_value_to_self_msat =
funding.value_to_self_msat + htlc_stats.pending_inbound_htlcs_value_msat - removed_outbound_total_msat;
let pending_remote_value_msat =
Expand Down Expand Up @@ -4372,13 +4377,17 @@ where
}

if !funding.is_outbound() {
let mut removed_outbound_total_msat = 0;
for htlc in self.pending_outbound_htlcs.iter() {
if let OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_, _)) | OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_, _)) = htlc.state {
removed_outbound_total_msat += htlc.amount_msat;
}
}

let removed_outbound_total_msat: u64 = self.pending_outbound_htlcs
.iter()
.filter_map(|htlc| {
matches!(
htlc.state,
OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_, _))
| OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_, _))
)
.then_some(htlc.amount_msat)
})
.sum();
let pending_value_to_self_msat =
funding.value_to_self_msat + htlc_stats.pending_inbound_htlcs_value_msat - removed_outbound_total_msat;
let pending_remote_value_msat =
Expand Down Expand Up @@ -4615,7 +4624,7 @@ where
broadcaster_dust_limit_sat,
logger,
);
debug_assert_eq!(stats, self.build_commitment_stats(funding, local, generated_by_local, None, None));
debug_assert_eq!(stats, self.build_commitment_stats(funding, local, generated_by_local, None, None), "Caught an inconsistency between `TxBuilder::build_commitment_transaction` and the rest of the `TxBuilder` methods");

// This populates the HTLC-source table with the indices from the HTLCs in the commitment
// transaction.
Expand Down
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