Add path field to PaymentPathFailed event

lightning/src/ln/channelmanager.rs

@@ -2875,7 +2875,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					self.fail_htlc_backwards_internal(channel_state,
 						htlc_src, &payment_hash, HTLCFailReason::Reason { failure_code, data: onion_failure_data});
 				},
-				HTLCSource::OutboundRoute { session_priv, mpp_id, .. } => {
+				HTLCSource::OutboundRoute { session_priv, mpp_id, path, .. } => {
 					let mut session_priv_bytes = [0; 32];
 					session_priv_bytes.copy_from_slice(&session_priv[..]);
 					let mut outbounds = self.pending_outbound_payments.lock().unwrap();
@@ -2887,6 +2887,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 									rejected_by_dest: false,
 									network_update: None,
 									all_paths_failed: sessions.get().len() == 0,
+									path: path.clone(),
 									#[cfg(test)]
 									error_code: None,
 									#[cfg(test)]
@@ -2956,6 +2957,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 								rejected_by_dest: !payment_retryable,
 								network_update,
 								all_paths_failed,
+								path: path.clone(),
 #[cfg(test)]
 								error_code: onion_error_code,
 #[cfg(test)]
@@ -2982,6 +2984,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 								rejected_by_dest: path.len() == 1,
 								network_update: None,
 								all_paths_failed,
+								path: path.clone(),
 #[cfg(test)]
 								error_code: Some(*failure_code),
 #[cfg(test)]

lightning/src/ln/functional_test_utils.rs

@@ -1399,10 +1399,13 @@ pub fn fail_payment_along_route<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expe
 			let events = origin_node.node.get_and_clear_pending_events();
 			assert_eq!(events.len(), 1);
 			match events[0] {
-				Event::PaymentPathFailed { payment_hash, rejected_by_dest, all_paths_failed, .. } => {
+				Event::PaymentPathFailed { payment_hash, rejected_by_dest, all_paths_failed, ref path, .. } => {
 					assert_eq!(payment_hash, our_payment_hash);
 					assert!(rejected_by_dest);
 					assert_eq!(all_paths_failed, i == expected_paths.len() - 1);
+					for (idx, hop) in expected_route.iter().enumerate() {
+						assert_eq!(hop.node.get_our_node_id(), path[idx].pubkey);
+					}
 				},
 				_ => panic!("Unexpected event"),
 			}

lightning/src/ln/functional_tests.rs

@@ -6068,7 +6068,7 @@ fn test_fail_holding_cell_htlc_upon_free() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 1);
 	match &events[0] {
-		&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update, ref error_code, ref error_data, ref all_paths_failed } => {
+		&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update, ref error_code, ref error_data, ref all_paths_failed, path: _ } => {
 			assert_eq!(our_payment_hash.clone(), *payment_hash);
 			assert_eq!(*rejected_by_dest, false);
 			assert_eq!(*all_paths_failed, true);
@@ -6155,7 +6155,7 @@ fn test_free_and_fail_holding_cell_htlcs() {
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 1);
 	match &events[0] {
-		&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update, ref error_code, ref error_data, ref all_paths_failed } => {
+		&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update, ref error_code, ref error_data, ref all_paths_failed, path: _ } => {
 			assert_eq!(payment_hash_2.clone(), *payment_hash);
 			assert_eq!(*rejected_by_dest, false);
 			assert_eq!(*all_paths_failed, true);

lightning/src/ln/onion_route_tests.rs

@@ -163,7 +163,7 @@ fn run_onion_failure_test_with_fail_intercept<F1,F2,F3>(_name: &str, test_case:
 
 	let events = nodes[0].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), 1);
-	if let &Event::PaymentPathFailed { payment_hash:_, ref rejected_by_dest, ref network_update, ref error_code, error_data: _, ref all_paths_failed } = &events[0] {
+	if let &Event::PaymentPathFailed { payment_hash:_, ref rejected_by_dest, ref network_update, ref error_code, error_data: _, ref all_paths_failed, path: _ } = &events[0] {
 		assert_eq!(*rejected_by_dest, !expected_retryable);
 		assert_eq!(*all_paths_failed, true);
 		assert_eq!(*error_code, expected_error_code);

lightning/src/routing/network_graph.rs

@@ -1729,6 +1729,7 @@ mod tests {
 				payment_hash: PaymentHash([0; 32]),
 				rejected_by_dest: false,
 				all_paths_failed: true,
+				path: vec![],
 				network_update: Some(NetworkUpdate::ChannelUpdateMessage {
 					msg: valid_channel_update,
 				}),
@@ -1752,6 +1753,7 @@ mod tests {
 				payment_hash: PaymentHash([0; 32]),
 				rejected_by_dest: false,
 				all_paths_failed: true,
+				path: vec![],
 				network_update: Some(NetworkUpdate::ChannelClosed {
 					short_channel_id,
 					is_permanent: false,
@@ -1774,6 +1776,7 @@ mod tests {
 				payment_hash: PaymentHash([0; 32]),
 				rejected_by_dest: false,
 				all_paths_failed: true,
+				path: vec![],
 				network_update: Some(NetworkUpdate::ChannelClosed {
 					short_channel_id,
 					is_permanent: true,

lightning/src/routing/router.rs

@@ -28,7 +28,7 @@ use core::cmp;
 use core::ops::Deref;
 
 /// A hop in a route
-#[derive(Clone, Hash, PartialEq, Eq)]
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct RouteHop {
 	/// The node_id of the node at this hop.
 	pub pubkey: PublicKey,

lightning/src/util/events.rs

@@ -19,6 +19,7 @@ use ln::msgs;
 use ln::msgs::DecodeError;
 use ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 use routing::network_graph::NetworkUpdate;
+use routing::router::RouteHop;
 use util::ser::{Writeable, Writer, MaybeReadable, Readable, VecReadWrapper, VecWriteWrapper};
 
 use bitcoin::blockdata::script::Script;
@@ -200,6 +201,8 @@ pub enum Event {
 		/// failed. This will be set to false if (1) this is an MPP payment and (2) other parts of the
 		/// larger MPP payment were still in flight when this event was generated.
 		all_paths_failed: bool,
+		/// The payment path that failed.
+		path: Vec<RouteHop>,
 #[cfg(test)]
 		error_code: Option<u16>,
 #[cfg(test)]
@@ -291,7 +294,8 @@ impl Writeable for Event {
 					(0, payment_preimage, required),
 				});
 			},
-			&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update, ref all_paths_failed,
+			&Event::PaymentPathFailed { ref payment_hash, ref rejected_by_dest, ref network_update,
+			                            ref all_paths_failed, ref path,
 				#[cfg(test)]
 				ref error_code,
 				#[cfg(test)]
@@ -307,6 +311,7 @@ impl Writeable for Event {
 					(1, network_update, option),
 					(2, rejected_by_dest, required),
 					(3, all_paths_failed, required),
+					(5, path, vec_type),
 				});
 			},
 			&Event::PendingHTLCsForwardable { time_forwardable: _ } => {
@@ -398,17 +403,20 @@ impl MaybeReadable for Event {
 					let mut rejected_by_dest = false;
 					let mut network_update = None;
 					let mut all_paths_failed = Some(true);
+					let mut path: Option<Vec<RouteHop>> = Some(vec![]);
 					read_tlv_fields!(reader, {
 						(0, payment_hash, required),
 						(1, network_update, ignorable),
 						(2, rejected_by_dest, required),
 						(3, all_paths_failed, option),
+						(5, path, vec_type),
 					});
 					Ok(Some(Event::PaymentPathFailed {
 						payment_hash,
 						rejected_by_dest,
 						network_update,
 						all_paths_failed: all_paths_failed.unwrap(),
+						path: path.unwrap(),
 						#[cfg(test)]
 						error_code,
 						#[cfg(test)]