Support abandoning pending outbound async payments.

Async payments may have very high expires because we may be waiting for days
for the recipient to come online, so it's important that users be able to
abandon these payments early if needed.

Author: valentinewallace

lightning/src/ln/outbound_payment.rs

@@ -218,20 +218,26 @@ impl PendingOutboundPayment {
 	}
 
 	fn mark_abandoned(&mut self, reason: PaymentFailureReason) {
-		if let PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } = self {
-			let mut our_session_privs = new_hash_set();
-			core::mem::swap(&mut our_session_privs, session_privs);
-			*self = PendingOutboundPayment::Abandoned {
-				session_privs: our_session_privs,
-				payment_hash: *payment_hash,
-				reason: Some(reason)
-			};
-		} else if let PendingOutboundPayment::InvoiceReceived { payment_hash, .. } = self {
-			*self = PendingOutboundPayment::Abandoned {
-				session_privs: new_hash_set(),
-				payment_hash: *payment_hash,
-				reason: Some(reason)
-			};
+		let session_privs = match self {
+			PendingOutboundPayment::Retryable { session_privs, .. } => {
+				let mut our_session_privs = new_hash_set();
+				core::mem::swap(&mut our_session_privs, session_privs);
+				our_session_privs
+			},
+			_ => new_hash_set(),
+		};
+		match self {
+			Self::Retryable { payment_hash, .. } |
+				Self::InvoiceReceived { payment_hash, .. } |
+				Self::StaticInvoiceReceived { payment_hash, .. } =>
+			{
+				*self = Self::Abandoned {
+					session_privs,
+					payment_hash: *payment_hash,
+					reason: Some(reason),
+				};
+			},
+			_ => {}
 		}
 	}
 
@@ -2789,4 +2795,44 @@ mod tests {
 			reason: Some(PaymentFailureReason::PaymentExpired),
 		}, None));
 	}
+
+	#[test]
+	fn abandon_unreleased_async_payment() {
+		let pending_events = Mutex::new(VecDeque::new());
+		let outbound_payments = OutboundPayments::new(new_hash_map());
+		let payment_id = PaymentId([0; 32]);
+		let absolute_expiry = 60;
+
+		let mut outbounds = outbound_payments.pending_outbound_payments.lock().unwrap();
+		let payment_params = PaymentParameters::from_node_id(test_utils::pubkey(42), 0)
+			.with_expiry_time(absolute_expiry);
+		let route_params = RouteParameters {
+			payment_params,
+			final_value_msat: 0,
+			max_total_routing_fee_msat: None,
+		};
+		let payment_hash = PaymentHash([0; 32]);
+		let outbound = PendingOutboundPayment::StaticInvoiceReceived {
+			payment_hash,
+			keysend_preimage: PaymentPreimage([0; 32]),
+			retry_strategy: Retry::Attempts(0),
+			payment_release_secret: [0; 32],
+			route_params,
+		};
+		outbounds.insert(payment_id, outbound);
+		core::mem::drop(outbounds);
+
+		outbound_payments.abandon_payment(
+			payment_id, PaymentFailureReason::UserAbandoned, &pending_events
+		);
+		let outbounds = outbound_payments.pending_outbound_payments.lock().unwrap();
+		assert_eq!(outbounds.len(), 0);
+		let events = pending_events.lock().unwrap();
+		assert_eq!(events.len(), 1);
+		assert_eq!(events[0], (Event::PaymentFailed {
+			payment_hash: Some(payment_hash),
+			payment_id,
+			reason: Some(PaymentFailureReason::UserAbandoned),
+		}, None));
+	}
 }