Expose ClaimId for each claim bump in BumpTransactionEvent

Author: wpaulino

lightning/src/chain/channelmonitor.rs

@@ -2502,7 +2502,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 		let mut ret = Vec::new();
 		mem::swap(&mut ret, &mut self.pending_events);
 		#[cfg(anchors)]
-		for claim_event in self.onchain_tx_handler.get_and_clear_pending_claim_events().drain(..) {
+		for (claim_id, claim_event) in self.onchain_tx_handler.get_and_clear_pending_claim_events().drain(..) {
 			match claim_event {
 				ClaimEvent::BumpCommitment {
 					package_target_feerate_sat_per_1000_weight, commitment_tx, anchor_output_idx,
@@ -2513,6 +2513,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 					let commitment_tx_fee_satoshis = self.channel_value_satoshis -
 						commitment_tx.output.iter().fold(0u64, |sum, output| sum + output.value);
 					ret.push(Event::BumpTransaction(BumpTransactionEvent::ChannelClose {
+						claim_id,
 						package_target_feerate_sat_per_1000_weight,
 						commitment_tx,
 						commitment_tx_fee_satoshis,
@@ -2544,6 +2545,7 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 						});
 					}
 					ret.push(Event::BumpTransaction(BumpTransactionEvent::HTLCResolution {
+						claim_id,
 						target_feerate_sat_per_1000_weight,
 						htlc_descriptors,
 						tx_lock_time,

lightning/src/chain/onchaintx.rs

@@ -475,10 +475,10 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
 	}
 
 	#[cfg(anchors)]
-	pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<ClaimEvent> {
+	pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
 		let mut events = Vec::new();
 		swap(&mut events, &mut self.pending_claim_events);
-		events.into_iter().map(|(_, event)| event).collect()
+		events.into_iter().collect()
 	}
 
 	/// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is

lightning/src/events/bump_transaction.rs

@@ -9,6 +9,7 @@
 
 //! Utitilies for bumping transactions originating from [`super::Event`]s.
 
+use crate::chain::ClaimId;
 use crate::ln::PaymentPreimage;
 use crate::ln::chan_utils;
 use crate::ln::chan_utils::{ChannelTransactionParameters, HTLCOutputInCommitment};
@@ -173,6 +174,15 @@ pub enum BumpTransactionEvent {
 	/// [`EcdsaChannelSigner::sign_holder_anchor_input`]: crate::sign::EcdsaChannelSigner::sign_holder_anchor_input
 	/// [`build_anchor_input_witness`]: crate::ln::chan_utils::build_anchor_input_witness
 	ChannelClose {
+		/// The unique identifier for the claim of the anchor output in the commitment transaction.
+		///
+		/// Any future instances of `ChannelClose` bump events that share the same `claim_id` must
+		/// be considered the same claim. Therefore, the idenfier serves as a "UTXO lock" for users,
+		/// as they can assign the additional inputs required for the claim to this identifier to
+		/// ensure their claims don't double spend and conflict with each other. However, note that
+		/// in some cases, it may be required to double spend the UTXOs assigned to previous claims
+		/// in new claims if there aren't any unassigned UTXOs available to use.
+		claim_id: ClaimId,
 		/// The target feerate that the transaction package, which consists of the commitment
 		/// transaction and the to-be-crafted child anchor transaction, must meet.
 		package_target_feerate_sat_per_1000_weight: u32,
@@ -222,6 +232,17 @@ pub enum BumpTransactionEvent {
 	/// [`EcdsaChannelSigner::sign_holder_htlc_transaction`]: crate::sign::EcdsaChannelSigner::sign_holder_htlc_transaction
 	/// [`HTLCDescriptor::tx_input_witness`]: HTLCDescriptor::tx_input_witness
 	HTLCResolution {
+		/// The unique identifier for the claim of the HTLCs in the confirmed commitment
+		/// transaction.
+		///
+		/// Any future instances of `HTLCResolution` bump events that share the same `claim_id` must
+		/// be considered the same claim, even if the set of HTLCs to claim has changed. Therefore,
+		/// the idenfier serves as a "UTXO lock" for users, as they can assign the additional inputs
+		/// required for the claim to this identifier to ensure their claims don't double spend and
+		/// conflict with each other. However, note that in some cases, it may be required to double
+		/// spend the UTXOs assigned to previous claims in new claims if there aren't any unassigned
+		/// UTXOs available to use.
+		claim_id: ClaimId,
 		/// The target feerate that the resulting HTLC transaction must meet.
 		target_feerate_sat_per_1000_weight: u32,
 		/// The set of pending HTLCs on the confirmed commitment that need to be claimed, preferably

lightning/src/ln/monitor_tests.rs

@@ -1785,7 +1785,7 @@ fn do_test_monitor_rebroadcast_pending_claims(anchors: bool) {
 			let mut feerate = 0;
 			#[cfg(anchors)] {
 				feerate = if let Event::BumpTransaction(BumpTransactionEvent::HTLCResolution {
-					target_feerate_sat_per_1000_weight, mut htlc_descriptors, tx_lock_time,
+					target_feerate_sat_per_1000_weight, mut htlc_descriptors, tx_lock_time, ..
 				}) = events.pop().unwrap() {
 					let secp = Secp256k1::new();
 					assert_eq!(htlc_descriptors.len(), 1);