Don't use UserAbandoned reason for auto-failing

A BOLT12 payment may be abandoned when handling the invoice or when
receiving an InvoiceError message. When abandoning the payment, don't
use UserAbandoned as the reason since that is meant for when the user
calls ChannelManager::abandon_payment.

Author: jkczyz

lightning/src/events/mod.rs

@@ -528,10 +528,13 @@ pub enum PaymentFailureReason {
 	/// This error should generally never happen. This likely means that there is a problem with
 	/// your router.
 	UnexpectedError,
+	/// An invoice was received that required unknown features.
+	UnknownRequiredFeatures,
 }
 
 impl_writeable_tlv_based_enum!(PaymentFailureReason,
 	(0, RecipientRejected) => {},
+	(1, UnknownRequiredFeatures) => {},
 	(2, UserAbandoned) => {},
 	(4, RetriesExhausted) => {},
 	(6, PaymentExpired) => {},
@@ -882,6 +885,7 @@ pub enum Event {
 		payment_hash: PaymentHash,
 		/// The reason the payment failed. This is only `None` for events generated or serialized
 		/// by versions prior to 0.0.115.
+		/// TODO: Will downgrading cause this to be None for UnknownRequiredFeatures?
 		reason: Option<PaymentFailureReason>,
 	},
 	/// Indicates that a path for an outbound payment was successful.

lightning/src/ln/channelmanager.rs

@@ -4270,8 +4270,12 @@ where
 	///
 	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 	pub fn abandon_payment(&self, payment_id: PaymentId) {
+		self.abandon_payment_with_reason(payment_id, PaymentFailureReason::UserAbandoned)
+	}
+
+	fn abandon_payment_with_reason(&self, payment_id: PaymentId, reason: PaymentFailureReason) {
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
-		self.pending_outbound_payments.abandon_payment(payment_id, PaymentFailureReason::UserAbandoned, &self.pending_events);
+		self.pending_outbound_payments.abandon_payment(payment_id, reason, &self.pending_events);
 	}
 
 	/// Send a spontaneous payment, which is a payment that does not require the recipient to have
@@ -10722,17 +10726,6 @@ where
 		let secp_ctx = &self.secp_ctx;
 		let expanded_key = &self.inbound_payment_key;
 
-		let abandon_if_payment = |context| {
-			match context {
-				Some(OffersContext::OutboundPayment { payment_id, nonce, hmac }) => {
-					if signer::verify_payment_id(payment_id, hmac, nonce, expanded_key) {
-						self.abandon_payment(payment_id);
-					}
-				},
-				_ => {},
-			}
-		};
-
 		match message {
 			OffersMessage::InvoiceRequest(invoice_request) => {
 				let responder = match responder {
@@ -10852,7 +10845,9 @@ where
 						logger, "Invoice requires unknown features: {:?}",
 						invoice.invoice_features(),
 					);
-					abandon_if_payment(context);
+					self.abandon_payment_with_reason(
+						payment_id, PaymentFailureReason::UnknownRequiredFeatures,
+					);
 
 					let error = InvoiceError::from(Bolt12SemanticError::UnknownRequiredFeatures);
 					let response = match responder {
@@ -10909,10 +10904,21 @@ where
 					Some(OffersContext::InboundPayment { payment_hash }) => Some(payment_hash),
 					_ => None,
 				};
+
 				let logger = WithContext::from(&self.logger, None, None, payment_hash);
 				log_trace!(logger, "Received invoice_error: {}", invoice_error);
 
-				abandon_if_payment(context);
+				match context {
+					Some(OffersContext::OutboundPayment { payment_id, nonce, hmac }) => {
+						if signer::verify_payment_id(payment_id, hmac, nonce, expanded_key) {
+							self.abandon_payment_with_reason(
+								payment_id, PaymentFailureReason::RecipientRejected,
+							);
+						}
+					},
+					_ => {},
+				}
+
 				ResponseInstruction::NoResponse
 			},
 		}