return NodeId from CandidateRouteHop::target function

Author: jbesraa

lightning/src/routing/router.rs

@@ -1002,6 +1002,7 @@ pub enum CandidateRouteHop<'a> {
 		/// `find_route` method.
 		details: &'a ChannelDetails,
 		/// The node id of the payer.
+		///
 		/// Can be accessed via `source` method.
 		node_id: NodeId
 	},
@@ -1011,9 +1012,9 @@ pub enum CandidateRouteHop<'a> {
 		info: DirectedChannelInfo<'a>,
 		/// The short_channel_id of the channel.
 		short_channel_id: u64,
-		/// The node id of the current hop in route.
+		/// The node id leading to the current hop in route.
 		source_node_id: NodeId,
-		/// The node id of next hop in route.
+		/// The node id of current hop in route.
 		target_node_id: NodeId,
 	},
 	/// A hop to the payee found in the BOLT 11 payment invoice, though not necessarily a direct
@@ -1022,8 +1023,8 @@ pub enum CandidateRouteHop<'a> {
 		/// Hint provides information about a private hop, needed while routing through a private
 		/// channel.
 		hint: &'a RouteHintHop,
-		/// The node id of the next hop in route.
-		target_node_id: NodeId
+		/// The node id of current hop in route.
+		target_node_id: NodeId,
 	},
 	/// The payee's identity is concealed behind blinded paths provided in a BOLT 12 invoice.
 	Blinded {
@@ -1038,6 +1039,10 @@ pub enum CandidateRouteHop<'a> {
 		/// Provided to uniquely identify a hop as we are
 		/// route building.
 		hint_idx: usize,
+		/// The node id of current hop in route.
+		///
+		/// This will always equal to `maybe_dummy_payee_node_id` in `find_route` method.
+		target_node_id: NodeId,
 	},
 	/// Similar to [`Self::Blinded`], but the path here has 1 blinded hop. `BlindedPayInfo` provided
 	/// for 1-hop blinded paths is ignored because it is meant to apply to the hops *between* the
@@ -1053,6 +1058,10 @@ pub enum CandidateRouteHop<'a> {
 		/// Provided to uniquely identify a hop as we are
 		/// route building.
 		hint_idx: usize,
+		/// The node id of current hop in route.
+		///
+		/// This will always equal to `maybe_dummy_payee_node_id` in `find_route` method.
+		target_node_id: NodeId,
 	},
 }
 
@@ -1152,6 +1161,11 @@ impl<'a> CandidateRouteHop<'a> {
 		}
 	}
 	/// Returns the source node id of this hop.
+	///
+	/// Source node id refers to the hop that is previous
+	/// to the current examined hop in route finding.
+	///
+	/// For `FirstHop` we return payer's node id.
 	pub fn source(&self) -> NodeId {
 		match self {
 			CandidateRouteHop::FirstHop { node_id, .. } => *node_id,
@@ -1162,13 +1176,17 @@ impl<'a> CandidateRouteHop<'a> {
 		}
 	}
 	/// Returns the target node id of this hop, if known.
- 	pub fn target(&self) -> Option<NodeId> {
+	///
+	/// Target node id refers to the current examined hop in route finding.
+	///
+	/// For `Blinded` and `OneHopBlinded` we return `maybe_dummy_payee_node_id` because we don't know the target.
+ 	pub fn target(&self) -> NodeId {
 		match self {
-			CandidateRouteHop::FirstHop { details, .. } => Some(details.counterparty.node_id.into()),
-			CandidateRouteHop::PublicHop { info, .. } => Some(info.channel.node_two.into()),
-			CandidateRouteHop::PrivateHop { target_node_id, .. } => Some(*target_node_id),
-			CandidateRouteHop::Blinded { hint, .. } => Some(hint.1.blinding_point.into()),
-			CandidateRouteHop::OneHopBlinded { hint, .. } => Some(hint.1.blinding_point.into())
+			CandidateRouteHop::FirstHop { details, .. } => details.counterparty.node_id.into(),
+			CandidateRouteHop::PublicHop { target_node_id, .. } => *target_node_id,
+			CandidateRouteHop::PrivateHop { target_node_id, .. } => *target_node_id,
+			CandidateRouteHop::Blinded { target_node_id, .. } => *target_node_id,
+			CandidateRouteHop::OneHopBlinded { target_node_id, .. } => *target_node_id,
 		}
 	}
 }
@@ -2170,8 +2188,8 @@ where L::Target: Logger {
 				network_nodes.get(&intro_node_id).is_some();
 			if !have_intro_node_in_graph || our_node_id == intro_node_id { continue }
 			let candidate = if hint.1.blinded_hops.len() == 1 {
-				CandidateRouteHop::OneHopBlinded { hint, hint_idx }
-			} else { CandidateRouteHop::Blinded { hint, hint_idx } };
+				CandidateRouteHop::OneHopBlinded { hint, hint_idx, target_node_id: maybe_dummy_payee_node_id }
+			} else { CandidateRouteHop::Blinded { hint, hint_idx, target_node_id: maybe_dummy_payee_node_id  } };
 			let mut path_contribution_msat = path_value_msat;
 			if let Some(hop_used_msat) = add_entry!(candidate, intro_node_id, maybe_dummy_payee_node_id,
 				0, path_contribution_msat, 0, 0_u64, 0, 0)