Add FundingContribution to SpliceFailed event

Replace the abandoned_funding_txo and channel_type fields on
Event::SpliceFailed with an Option<FundingContribution> from the failed
round. Users can feed this back to funding_contributed to retry or use
it to inform a fresh attempt via splice_channel.

Also makes FundingContribution::feerate() public so users can inspect
the feerate when deciding whether to retry or bump.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jkczyz

lightning/src/events/mod.rs

@@ -25,6 +25,7 @@ use crate::blinded_path::payment::{
 use crate::chain::transaction;
 use crate::ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
 use crate::ln::channelmanager::{InterceptId, PaymentId};
+use crate::ln::funding::FundingContribution;
 use crate::ln::msgs;
 use crate::ln::onion_utils::LocalHTLCFailureReason;
 use crate::ln::outbound_payment::RecipientOnionFields;
@@ -1621,19 +1622,20 @@ pub enum Event {
 		/// The witness script that is used to lock the channel's funding output to commitment transactions.
 		new_funding_redeem_script: ScriptBuf,
 	},
-	/// Used to indicate that a splice for the given `channel_id` has failed.
+	/// Used to indicate that a splice negotiation round for the given `channel_id` has failed.
 	///
-	/// This event may be emitted if a splice fails after it has been initiated but prior to signing
-	/// any negotiated funding transaction.
+	/// Each splice attempt (initial or RBF) resolves to either [`Event::SplicePending`] on
+	/// success or this event on failure. Prior successfully negotiated splice transactions are
+	/// unaffected.
 	///
-	/// Any UTXOs contributed to be spent by the funding transaction may be reused and will be
-	/// given in `contributed_inputs`.
+	/// Any UTXOs contributed to the failed round that are not committed to a prior negotiated
+	/// splice transaction will be returned via a preceding [`Event::DiscardFunding`].
 	///
 	/// # Failure Behavior and Persistence
 	/// This event will eventually be replayed after failures-to-handle (i.e., the event handler
 	/// returning `Err(ReplayEvent ())`) and will be persisted across restarts.
 	SpliceFailed {
-		/// The `channel_id` of the channel for which the splice failed.
+		/// The `channel_id` of the channel for which the splice negotiation round failed.
 		channel_id: ChannelId,
 		/// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
 		/// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels.
@@ -1643,12 +1645,17 @@ pub enum Event {
 		user_channel_id: u128,
 		/// The `node_id` of the channel counterparty.
 		counterparty_node_id: PublicKey,
-		/// The outpoint of the channel's splice funding transaction, if one was created.
-		abandoned_funding_txo: Option<OutPoint>,
-		/// The features that this channel will operate with, if available.
-		channel_type: Option<ChannelTypeFeatures>,
 		/// The reason the splice negotiation failed.
 		reason: NegotiationFailureReason,
+		/// The funding contribution from the failed negotiation round, if available. This can be
+		/// fed back to [`ChannelManager::funding_contributed`] to retry with the same parameters.
+		/// Alternatively, call [`ChannelManager::splice_channel`] to obtain a fresh
+		/// [`FundingTemplate`] and build a new contribution.
+		///
+		/// [`ChannelManager::funding_contributed`]: crate::ln::channelmanager::ChannelManager::funding_contributed
+		/// [`ChannelManager::splice_channel`]: crate::ln::channelmanager::ChannelManager::splice_channel
+		/// [`FundingTemplate`]: crate::ln::channelmanager::FundingTemplate
+		contribution: Option<FundingContribution>,
 	},
 	/// Used to indicate to the user that they can abandon the funding transaction and recycle the
 	/// inputs for another purpose.
@@ -2440,18 +2447,16 @@ impl Writeable for Event {
 				ref channel_id,
 				ref user_channel_id,
 				ref counterparty_node_id,
-				ref abandoned_funding_txo,
-				ref channel_type,
 				ref reason,
+				ref contribution,
 			} => {
 				52u8.write(writer)?;
 				write_tlv_fields!(writer, {
 					(1, channel_id, required),
-					(3, channel_type, option),
 					(5, user_channel_id, required),
 					(7, counterparty_node_id, required),
-					(9, abandoned_funding_txo, option),
 					(11, reason, required),
+					(13, contribution, option),
 				});
 			},
 			// Note that, going forward, all new events must only write data inside of
@@ -3092,20 +3097,18 @@ impl MaybeReadable for Event {
 				let mut f = || {
 					_init_and_read_len_prefixed_tlv_fields!(reader, {
 						(1, channel_id, required),
-						(3, channel_type, option),
 						(5, user_channel_id, required),
 						(7, counterparty_node_id, required),
-						(9, abandoned_funding_txo, option),
 						(11, reason, (default_value, NegotiationFailureReason::Unknown)),
+						(13, contribution, option),
 					});
 
 					Ok(Some(Event::SpliceFailed {
 						channel_id: channel_id.0.unwrap(),
 						user_channel_id: user_channel_id.0.unwrap(),
 						counterparty_node_id: counterparty_node_id.0.unwrap(),
-						abandoned_funding_txo,
-						channel_type,
 						reason: reason.0.unwrap(),
+						contribution,
 					}))
 				};
 				f()

lightning/src/ln/channel.rs

@@ -7040,6 +7040,9 @@ pub struct SpliceFundingFailed {
 
 	/// Outputs contributed to the splice transaction.
 	pub contributed_outputs: Vec<bitcoin::TxOut>,
+
+	/// The funding contribution from the failed round, if available.
+	pub contribution: Option<FundingContribution>,
 }
 
 macro_rules! maybe_create_splice_funding_failed {
@@ -7088,11 +7091,15 @@ macro_rules! maybe_create_splice_funding_failed {
 					return None;
 				}
 
+				let contribution =
+					$pending_splice_ref.and_then(|ps| ps.contributions.last().cloned());
+
 				Some(SpliceFundingFailed {
 					funding_txo,
 					channel_type,
 					contributed_inputs,
 					contributed_outputs,
+					contribution,
 				})
 			})
 	}};
@@ -7124,6 +7131,7 @@ where
 	/// Builds a [`SpliceFundingFailed`] from a contribution, filtering out inputs/outputs
 	/// that are still committed to a prior splice round.
 	fn splice_funding_failed_for(&self, contribution: FundingContribution) -> SpliceFundingFailed {
+		let cloned_contribution = contribution.clone();
 		let (mut inputs, mut outputs) = contribution.into_contributed_inputs_and_outputs();
 		if let Some(ref pending_splice) = self.pending_splice {
 			for input in pending_splice.contributed_inputs() {
@@ -7138,6 +7146,7 @@ where
 			channel_type: None,
 			contributed_inputs: inputs,
 			contributed_outputs: outputs,
+			contribution: Some(cloned_contribution),
 		}
 	}
 

lightning/src/ln/channelmanager.rs

@@ -4113,8 +4113,7 @@ impl<
 									channel_id: *chan_id,
 									counterparty_node_id: *counterparty_node_id,
 									user_channel_id: chan.context().get_user_id(),
-									abandoned_funding_txo: splice_funding_failed.funding_txo,
-									channel_type: splice_funding_failed.channel_type,
+									contribution: splice_funding_failed.contribution,
 									reason: events::NegotiationFailureReason::ChannelClosing,
 								},
 								None,
@@ -4420,8 +4419,7 @@ impl<
 						channel_id: shutdown_res.channel_id,
 						counterparty_node_id: shutdown_res.counterparty_node_id,
 						user_channel_id: shutdown_res.user_channel_id,
-						abandoned_funding_txo: splice_funding_failed.funding_txo,
-						channel_type: splice_funding_failed.channel_type,
+						contribution: splice_funding_failed.contribution,
 						reason: events::NegotiationFailureReason::ChannelClosing,
 					},
 					None,
@@ -4927,8 +4925,7 @@ impl<
 								channel_id: *channel_id,
 								counterparty_node_id: *counterparty_node_id,
 								user_channel_id: chan.context.get_user_id(),
-								abandoned_funding_txo: splice_funding_failed.funding_txo,
-								channel_type: splice_funding_failed.channel_type,
+								contribution: splice_funding_failed.contribution,
 								reason: events::NegotiationFailureReason::LocallyAbandoned,
 							},
 							None,
@@ -6614,10 +6611,7 @@ impl<
 			},
 			QuiescentError::FailSplice(
 				SpliceFundingFailed {
-					funding_txo,
-					channel_type,
-					contributed_inputs,
-					contributed_outputs,
+					contributed_inputs, contributed_outputs, contribution, ..
 				},
 				reason,
 			) => {
@@ -6627,9 +6621,8 @@ impl<
 						channel_id,
 						counterparty_node_id,
 						user_channel_id,
-						abandoned_funding_txo: funding_txo,
-						channel_type,
 						reason,
+						contribution,
 					},
 					None,
 				));
@@ -11863,8 +11856,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 									channel_id,
 									counterparty_node_id: *counterparty_node_id,
 									user_channel_id: channel.context().get_user_id(),
-									abandoned_funding_txo: splice_funding_failed.funding_txo,
-									channel_type: splice_funding_failed.channel_type.clone(),
+									contribution: splice_funding_failed.contribution.clone(),
 									reason: events::NegotiationFailureReason::NegotiationError,
 								},
 								None,
@@ -12023,8 +12015,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 									channel_id: msg.channel_id,
 									counterparty_node_id,
 									user_channel_id: chan.context().get_user_id(),
-									abandoned_funding_txo: splice_funding_failed.funding_txo,
-									channel_type: splice_funding_failed.channel_type.clone(),
+									contribution: splice_funding_failed.contribution.clone(),
 									reason: events::NegotiationFailureReason::NegotiationError,
 								},
 								None,
@@ -12194,8 +12185,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 								channel_id: msg.channel_id,
 								counterparty_node_id: *counterparty_node_id,
 								user_channel_id: chan_entry.get().context().get_user_id(),
-								abandoned_funding_txo: splice_funding_failed.funding_txo,
-								channel_type: splice_funding_failed.channel_type,
+								contribution: splice_funding_failed.contribution,
 								reason: events::NegotiationFailureReason::CounterpartyAborted,
 							},
 							None,
@@ -12343,8 +12333,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 									channel_id: msg.channel_id,
 									counterparty_node_id: *counterparty_node_id,
 									user_channel_id: chan.context().get_user_id(),
-									abandoned_funding_txo: splice_funding_failed.funding_txo,
-									channel_type: splice_funding_failed.channel_type,
+									contribution: splice_funding_failed.contribution,
 									reason: events::NegotiationFailureReason::ChannelClosing,
 								},
 								None,
@@ -15460,8 +15449,7 @@ impl<
 								channel_id: chan.context().channel_id(),
 								counterparty_node_id,
 								user_channel_id: chan.context().get_user_id(),
-								abandoned_funding_txo: splice_funding_failed.funding_txo,
-								channel_type: splice_funding_failed.channel_type,
+								contribution: splice_funding_failed.contribution,
 								reason: events::NegotiationFailureReason::PeerDisconnected,
 							});
 							splice_failed_events.push(events::Event::DiscardFunding {
@@ -18133,9 +18121,8 @@ impl<
 							channel_id: chan.context.channel_id(),
 							counterparty_node_id: chan.context.get_counterparty_node_id(),
 							user_channel_id: chan.context.get_user_id(),
-							abandoned_funding_txo: splice_funding_failed.funding_txo,
-							channel_type: splice_funding_failed.channel_type,
 							reason: events::NegotiationFailureReason::PeerDisconnected,
+							contribution: splice_funding_failed.contribution,
 						},
 						None,
 					));

lightning/src/ln/functional_test_utils.rs

@@ -3248,9 +3248,10 @@ pub fn expect_splice_failed_events<'a, 'b, 'c, 'd>(
 	let events = node.node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 2);
 	match &events[0] {
-		Event::SpliceFailed { channel_id, reason, .. } => {
+		Event::SpliceFailed { channel_id, reason, contribution, .. } => {
 			assert_eq!(*expected_channel_id, *channel_id);
 			assert_eq!(*reason, expected_reason);
+			assert_eq!(contribution.as_ref(), Some(&funding_contribution));
 		},
 		_ => panic!("Unexpected event"),
 	}

lightning/src/ln/funding.rs

@@ -710,7 +710,8 @@ impl_writeable_tlv_based!(FundingContribution, {
 });
 
 impl FundingContribution {
-	pub(super) fn feerate(&self) -> FeeRate {
+	/// Returns the feerate of this contribution.
+	pub fn feerate(&self) -> FeeRate {
 		self.feerate
 	}
 
@@ -731,6 +732,11 @@ impl FundingContribution {
 		self.value_added
 	}
 
+	/// Returns the inputs included in this contribution.
+	pub fn inputs(&self) -> &[FundingTxInput] {
+		&self.inputs
+	}
+
 	/// Returns the outputs (e.g., withdrawal destinations) included in this contribution.
 	///
 	/// This does not include the change output; see [`FundingContribution::change_output`].

lightning/src/ln/splicing_tests.rs

@@ -3059,9 +3059,10 @@ fn do_abandon_splice_quiescent_action_on_shutdown(local_shutdown: bool, pending_
 		let events = nodes[0].node.get_and_clear_pending_events();
 		assert_eq!(events.len(), 2, "{events:?}");
 		match &events[0] {
-			Event::SpliceFailed { channel_id: cid, reason, .. } => {
+			Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 				assert_eq!(*cid, channel_id);
 				assert_eq!(*reason, NegotiationFailureReason::ChannelClosing);
+				assert!(contribution.is_some());
 			},
 			other => panic!("Expected SpliceFailed, got {:?}", other),
 		}
@@ -4457,9 +4458,10 @@ fn test_splice_acceptor_disconnect_emits_events() {
 	let events = nodes[1].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 2, "{events:?}");
 	match &events[0] {
-		Event::SpliceFailed { channel_id: cid, reason, .. } => {
+		Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 			assert_eq!(*cid, channel_id);
 			assert_eq!(*reason, NegotiationFailureReason::PeerDisconnected);
+			assert!(contribution.is_some());
 		},
 		other => panic!("Expected SpliceFailed, got {:?}", other),
 	}
@@ -5912,9 +5914,10 @@ fn test_splice_rbf_acceptor_contributes_then_disconnects() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 2, "{events:?}");
 	match &events[0] {
-		Event::SpliceFailed { channel_id: cid, reason, .. } => {
+		Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 			assert_eq!(*cid, channel_id);
 			assert_eq!(*reason, NegotiationFailureReason::PeerDisconnected);
+			assert!(contribution.is_some());
 		},
 		other => panic!("Expected SpliceFailed, got {:?}", other),
 	}
@@ -5994,9 +5997,10 @@ fn test_splice_rbf_disconnect_filters_prior_contributions() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 2, "{events:?}");
 	match &events[0] {
-		Event::SpliceFailed { channel_id: cid, reason, .. } => {
+		Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 			assert_eq!(*cid, channel_id);
 			assert_eq!(*reason, NegotiationFailureReason::PeerDisconnected);
+			assert!(contribution.is_some());
 		},
 		other => panic!("Expected SpliceFailed, got {:?}", other),
 	}
@@ -6036,9 +6040,10 @@ fn test_splice_rbf_disconnect_filters_prior_contributions() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 2, "{events:?}");
 	match &events[0] {
-		Event::SpliceFailed { channel_id: cid, reason, .. } => {
+		Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 			assert_eq!(*cid, channel_id);
 			assert_eq!(*reason, NegotiationFailureReason::PeerDisconnected);
+			assert!(contribution.is_some());
 		},
 		other => panic!("Expected SpliceFailed, got {:?}", other),
 	}
@@ -6726,9 +6731,10 @@ fn test_splice_rbf_rejects_own_low_feerate_after_several_attempts() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 1, "{events:?}");
 	match &events[0] {
-		Event::SpliceFailed { channel_id: cid, reason, .. } => {
+		Event::SpliceFailed { channel_id: cid, reason, contribution, .. } => {
 			assert_eq!(*cid, channel_id);
 			assert_eq!(*reason, NegotiationFailureReason::FeeRateTooLow);
+			assert!(contribution.is_some());
 		},
 		other => panic!("Expected SpliceFailed, got {:?}", other),
 	}