Return new funding_txo with splice_locked

When sending or receiving splice_locked results in promoting a
FundingScope, return the new funding_txo to ChannelManager. This is used
to determine if Event::ChannelReady should be emitted. This is deemed
safer than checking the channel if there are any pending splices after
it handles splice_locked or after checking funding confirmations.

Author: jkczyz

lightning/src/ln/channel.rs

@@ -2188,7 +2188,6 @@ impl PendingSplice {
 			},
 		}
 	}
-
 }
 
 /// Wrapper around a [`Transaction`] useful for caching the result of [`Transaction::compute_txid`].
@@ -9279,12 +9278,18 @@ where
 						&self.context.channel_id,
 					);
 
-					let announcement_sigs = self
-						.maybe_promote_splice_funding(confirmed_funding_index, logger)
+					let funding_promoted =
+						self.maybe_promote_splice_funding(confirmed_funding_index, logger);
+					let funding_txo = funding_promoted.then(|| {
+						self.funding
+							.get_funding_txo()
+							.expect("Splice FundingScope should always have a funding_txo")
+					});
+					let announcement_sigs = funding_promoted
 						.then(|| self.get_announcement_sigs(node_signer, chain_hash, user_config, height, logger))
 						.flatten();
 
-					return Ok((Some(FundingConfirmedMessage::Splice(splice_locked)), announcement_sigs));
+					return Ok((Some(FundingConfirmedMessage::Splice(splice_locked, funding_txo)), announcement_sigs));
 				}
 			}
 
@@ -9442,16 +9447,22 @@ where
 			if let Some(splice_locked) = pending_splice.check_get_splice_locked(&self.context, funding, height) {
 				log_info!(logger, "Sending a splice_locked to our peer for channel {}", &self.context.channel_id);
 
-				let announcement_sigs = self
-					.maybe_promote_splice_funding(confirmed_funding_index, logger)
+				let funding_promoted =
+					self.maybe_promote_splice_funding(confirmed_funding_index, logger);
+				let funding_txo = funding_promoted.then(|| {
+					self.funding
+						.get_funding_txo()
+						.expect("Splice FundingScope should always have a funding_txo")
+				});
+				let announcement_sigs = funding_promoted
 					.then(|| chain_node_signer
 						.and_then(|(chain_hash, node_signer, user_config)|
 							self.get_announcement_sigs(node_signer, chain_hash, user_config, height, logger)
 						)
 					)
 					.flatten();
 
-				return Ok((Some(FundingConfirmedMessage::Splice(splice_locked)), timed_out_htlcs, announcement_sigs));
+				return Ok((Some(FundingConfirmedMessage::Splice(splice_locked, funding_txo)), timed_out_htlcs, announcement_sigs));
 			}
 		}
 
@@ -9945,7 +9956,7 @@ where
 	pub fn splice_locked<NS: Deref, L: Deref>(
 		&mut self, msg: &msgs::SpliceLocked, node_signer: &NS, chain_hash: ChainHash,
 		user_config: &UserConfig, best_block: &BestBlock, logger: &L,
-	) -> Result<Option<msgs::AnnouncementSignatures>, ChannelError>
+	) -> Result<(Option<OutPoint>, Option<msgs::AnnouncementSignatures>), ChannelError>
 	where
 		NS::Target: NodeSigner,
 		L::Target: Logger,
@@ -9978,13 +9989,18 @@ where
 						&self.context.channel_id,
 					);
 					promote_splice_funding!(self, funding);
-					return Ok(self.get_announcement_sigs(
+					let funding_txo = self
+						.funding
+						.get_funding_txo()
+						.expect("Splice FundingScope should always have a funding_txo");
+					let announcement_sigs = self.get_announcement_sigs(
 						node_signer,
 						chain_hash,
 						user_config,
 						best_block.height,
 						logger,
-					));
+					);
+					return Ok((Some(funding_txo), announcement_sigs));
 				}
 
 				let err = "unknown splice funding txid";
@@ -10008,7 +10024,7 @@ where
 		}
 
 		pending_splice.received_funding_txid = Some(msg.splice_txid);
-		Ok(None)
+		Ok((None, None))
 	}
 
 	// Send stuff to our remote peers:
@@ -10735,11 +10751,6 @@ where
 		}
 	}
 
-	#[cfg(splicing)]
-	pub fn has_pending_splice(&self) -> bool {
-		self.pending_splice.is_some()
-	}
-
 	pub fn remove_legacy_scids_before_block(&mut self, height: u32) -> alloc::vec::Drain<u64> {
 		let end = self
 			.funding

lightning/src/ln/channelmanager.rs

@@ -10166,10 +10166,10 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 						&self.best_block.read().unwrap(),
 						&&logger,
 					);
-					let announcement_sigs_opt =
+					let (funding_txo, announcement_sigs_opt) =
 						try_channel_entry!(self, peer_state, result, chan_entry);
 
-					if !chan.has_pending_splice() {
+					if funding_txo.is_some() {
 						let mut short_to_chan_info = self.short_to_chan_info.write().unwrap();
 						insert_short_channel_id!(short_to_chan_info, chan);
 
@@ -10179,9 +10179,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
 								channel_id: chan.context.channel_id(),
 								user_channel_id: chan.context.get_user_id(),
 								counterparty_node_id: chan.context.get_counterparty_node_id(),
-								funding_txo: chan
-									.funding
-									.get_funding_txo()
+								funding_txo: funding_txo
 									.map(|outpoint| outpoint.into_bitcoin_outpoint()),
 								channel_type: chan.funding.get_channel_type().clone(),
 							},
@@ -12224,7 +12222,7 @@ where
 pub(super) enum FundingConfirmedMessage {
 	Establishment(msgs::ChannelReady),
 	#[cfg(splicing)]
-	Splice(msgs::SpliceLocked),
+	Splice(msgs::SpliceLocked, Option<OutPoint>),
 }
 
 impl<
@@ -12298,8 +12296,8 @@ where
 										}
 									},
 									#[cfg(splicing)]
-									Some(FundingConfirmedMessage::Splice(splice_locked)) => {
-										if !funded_channel.has_pending_splice() {
+									Some(FundingConfirmedMessage::Splice(splice_locked, funding_txo)) => {
+										if funding_txo.is_some() {
 											let mut short_to_chan_info = self.short_to_chan_info.write().unwrap();
 											insert_short_channel_id!(short_to_chan_info, funded_channel);
 
@@ -12308,7 +12306,7 @@ where
 												channel_id: funded_channel.context.channel_id(),
 												user_channel_id: funded_channel.context.get_user_id(),
 												counterparty_node_id: funded_channel.context.get_counterparty_node_id(),
-												funding_txo: funded_channel.funding.get_funding_txo().map(|outpoint| outpoint.into_bitcoin_outpoint()),
+												funding_txo: funding_txo.map(|outpoint| outpoint.into_bitcoin_outpoint()),
 												channel_type: funded_channel.funding.get_channel_type().clone(),
 											}, None));
 										}