Add `counterparty_node_id` to `Event::SpendableOutputs`

diff --git a/lightning-background-processor/src/lib.rs b/lightning-background-processor/src/lib.rs
index bb99d65..d34ef7d 100644
--- a/lightning-background-processor/src/lib.rs
+++ b/lightning-background-processor/src/lib.rs
@@ -3110,7 +3110,7 @@ mod tests {
 		let event =
 			receiver.recv_timeout(EVENT_DEADLINE).expect("Events not handled within deadline");
 		match event {
-			Event::SpendableOutputs { outputs, channel_id } => {
+			Event::SpendableOutputs { outputs, channel_id, counterparty_node_id: _ } => {
 				nodes[0]
 					.sweeper
 					.track_spendable_outputs(outputs, channel_id, false, Some(153))
diff --git a/lightning-tests/src/upgrade_downgrade_tests.rs b/lightning-tests/src/upgrade_downgrade_tests.rs
index 8df6703..14b0a5c 100644
--- a/lightning-tests/src/upgrade_downgrade_tests.rs
+++ b/lightning-tests/src/upgrade_downgrade_tests.rs
@@ -308,7 +308,9 @@ fn test_0_1_legacy_remote_key_derivation() {
 	connect_blocks(&nodes[0], ANTI_REORG_DELAY - 1);
 	let mut spendable_event = nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events();
 	assert_eq!(spendable_event.len(), 1);
-	if let Event::SpendableOutputs { outputs, channel_id: ev_id } = spendable_event.pop().unwrap() {
+	if let Event::SpendableOutputs { outputs, channel_id: ev_id, counterparty_node_id: _ } =
+		spendable_event.pop().unwrap()
+	{
 		assert_eq!(ev_id.unwrap().0, channel_id);
 		assert_eq!(outputs.len(), 1);
 		let spk = Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script();
diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index a537ff5..b109466 100644
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -5619,6 +5619,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 					self.pending_events.push(Event::SpendableOutputs {
 						outputs: vec![descriptor],
 						channel_id: Some(self.channel_id()),
+						counterparty_node_id: Some(self.counterparty_node_id),
 					});
 					self.spendable_txids_confirmed.push(entry.txid);
 				},
diff --git a/lightning/src/events/mod.rs b/lightning/src/events/mod.rs
index 3d860e9..a5ac08b 100644
--- a/lightning/src/events/mod.rs
+++ b/lightning/src/events/mod.rs
@@ -1318,6 +1318,10 @@ pub enum Event {
 		///
 		/// This will always be `Some` for events generated by LDK versions 0.0.117 and above.
 		channel_id: Option<ChannelId>,
+		/// The `node_id` of the channel counterparty.
+		///
+		/// This will always be `Some` for events generated by LDK versions 0.3 and above.
+		counterparty_node_id: Option<PublicKey>,
 	},
 	/// This event is generated when a payment has been successfully forwarded through us and a
 	/// forwarding fee earned.
@@ -2012,11 +2016,12 @@ impl Writeable for Event {
 				});
 			},
 			// 4u8 used to be `PendingHTLCsForwardable`
-			&Event::SpendableOutputs { ref outputs, channel_id } => {
+			&Event::SpendableOutputs { ref outputs, channel_id, counterparty_node_id } => {
 				5u8.write(writer)?;
 				write_tlv_fields!(writer, {
 					(0, WithoutLength(outputs), required),
 					(1, channel_id, option),
+					(3, counterparty_node_id, option),
 				});
 			},
 			&Event::HTLCIntercepted {
@@ -2521,11 +2526,17 @@ impl MaybeReadable for Event {
 				let mut f = || {
 					let mut outputs = WithoutLength(Vec::new());
 					let mut channel_id: Option<ChannelId> = None;
+					let mut counterparty_node_id: Option<PublicKey> = None;
 					read_tlv_fields!(reader, {
 						(0, outputs, required),
 						(1, channel_id, option),
+						(3, counterparty_node_id, option),
 					});
-					Ok(Some(Event::SpendableOutputs { outputs: outputs.0, channel_id }))
+					Ok(Some(Event::SpendableOutputs {
+						outputs: outputs.0,
+						channel_id,
+						counterparty_node_id,
+					}))
 				};
 				f()
 			},
diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs
index 8e854b3..a7a062a 100644
--- a/lightning/src/ln/functional_tests.rs
+++ b/lightning/src/ln/functional_tests.rs
@@ -3430,7 +3430,7 @@ macro_rules! check_spendable_outputs {
 		let secp_ctx = Secp256k1::new();
 		for event in events.drain(..) {
 			match event {
-				Event::SpendableOutputs { mut outputs, channel_id: _ } => {
+				Event::SpendableOutputs { mut outputs, channel_id: _, counterparty_node_id: _ } => {
 					for outp in outputs.drain(..) {
 						let script =
 							Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script();
diff --git a/lightning/src/ln/monitor_tests.rs b/lightning/src/ln/monitor_tests.rs
index 097266c..aebd83a 100644
--- a/lightning/src/ln/monitor_tests.rs
+++ b/lightning/src/ln/monitor_tests.rs
@@ -2209,7 +2209,7 @@ fn do_test_revoked_counterparty_aggregated_claims(keyed_anchors: bool, p2a_ancho
 	let spendable_output_events = nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events();
 	assert_eq!(spendable_output_events.len(), 2);
 	for event in spendable_output_events {
-		if let Event::SpendableOutputs { outputs, channel_id: _ } = event {
+		if let Event::SpendableOutputs { outputs, channel_id: _, counterparty_node_id: _ } = event {
 			assert_eq!(outputs.len(), 1);
 			let spend_tx = nodes[1].keys_manager.backing.spend_spendable_outputs(
 				&[&outputs[0]], Vec::new(), ScriptBuf::new_op_return(&[]), 253, None, &Secp256k1::new(),
@@ -2992,7 +2992,7 @@ fn do_test_anchors_aggregated_revoked_htlc_tx(p2a_anchor: bool) {
 	// - 1 static to_remote output.
 	assert_eq!(spendable_output_events.len(), 4);
 	for event in spendable_output_events {
-		if let Event::SpendableOutputs { outputs, channel_id } = event {
+		if let Event::SpendableOutputs { outputs, channel_id, counterparty_node_id: _ } = event {
 			assert_eq!(outputs.len(), 1);
 			assert!([chan_b.2, chan_a.2].contains(&channel_id.unwrap()));
 			let spend_tx = nodes[0].keys_manager.backing.spend_spendable_outputs(
diff --git a/lightning/src/ln/reorg_tests.rs b/lightning/src/ln/reorg_tests.rs
index b56caf9..25ad031 100644
--- a/lightning/src/ln/reorg_tests.rs
+++ b/lightning/src/ln/reorg_tests.rs
@@ -622,7 +622,7 @@ fn do_test_to_remote_after_local_detection(style: ConnectStyle) {
 
 	let mut node_a_spendable = nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events();
 	assert_eq!(node_a_spendable.len(), 1);
-	if let Event::SpendableOutputs { outputs, channel_id } = node_a_spendable.pop().unwrap() {
+	if let Event::SpendableOutputs { outputs, channel_id, counterparty_node_id: _ } = node_a_spendable.pop().unwrap() {
 		assert_eq!(outputs.len(), 1);
 		assert_eq!(channel_id, Some(chan_id));
 		let spend_tx = nodes[0].keys_manager.backing.spend_spendable_outputs(&[&outputs[0]], Vec::new(),
@@ -643,7 +643,7 @@ fn do_test_to_remote_after_local_detection(style: ConnectStyle) {
 
 	let mut node_b_spendable = nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events();
 	assert_eq!(node_b_spendable.len(), 1);
-	if let Event::SpendableOutputs { outputs, channel_id } = node_b_spendable.pop().unwrap() {
+	if let Event::SpendableOutputs { outputs, channel_id, counterparty_node_id: _ } = node_b_spendable.pop().unwrap() {
 		assert_eq!(outputs.len(), 1);
 		assert_eq!(channel_id, Some(chan_id));
 		let spend_tx = nodes[1].keys_manager.backing.spend_spendable_outputs(&[&outputs[0]], Vec::new(),