Remove deprecated send_payment_with_route usage from fuzzing

This allows us to make the PaymentSendFailure error type private, as well as
reduce the visibility of the vestigial send_payment_with_route method that was
already made test and fuzz-only in a previous commit.

fuzz/src/chanmon_consistency.rs

@@ -47,8 +47,8 @@ use lightning::events::MessageSendEventsProvider;
 use lightning::ln::channel::FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE;
 use lightning::ln::channel_state::ChannelDetails;
 use lightning::ln::channelmanager::{
-	ChainParameters, ChannelManager, ChannelManagerReadArgs, PaymentId, PaymentSendFailure,
-	RecipientOnionFields,
+	ChainParameters, ChannelManager, ChannelManagerReadArgs, PaymentId,
+	RecipientOnionFields, Retry
 };
 use lightning::ln::functional_test_utils::*;
 use lightning::ln::msgs::{
@@ -58,7 +58,7 @@ use lightning::ln::script::ShutdownScript;
 use lightning::ln::types::ChannelId;
 use lightning::offers::invoice::UnsignedBolt12Invoice;
 use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath};
-use lightning::routing::router::{InFlightHtlcs, Path, Route, RouteHop, RouteParameters, Router};
+use lightning::routing::router::{InFlightHtlcs, Path, PaymentParameters, Route, RouteHop, RouteParameters, Router};
 use lightning::sign::{
 	EntropySource, InMemorySigner, KeyMaterial, NodeSigner, Recipient, SignerProvider,
 };
@@ -82,6 +82,7 @@ use bitcoin::secp256k1::{self, Message, PublicKey, Scalar, Secp256k1, SecretKey}
 
 use lightning::io::Cursor;
 use std::cmp::{self, Ordering};
+use std::collections::VecDeque;
 use std::mem;
 use std::sync::atomic;
 use std::sync::{Arc, Mutex};
@@ -112,13 +113,18 @@ impl FeeEstimator for FuzzEstimator {
 	}
 }
 
-struct FuzzRouter {}
+struct FuzzRouter {
+	pub next_routes: Mutex<VecDeque<Route>>,
+}
 
 impl Router for FuzzRouter {
 	fn find_route(
 		&self, _payer: &PublicKey, _params: &RouteParameters,
 		_first_hops: Option<&[&ChannelDetails]>, _inflight_htlcs: InFlightHtlcs,
 	) -> Result<Route, msgs::LightningError> {
+		if let Some(route) = self.next_routes.lock().unwrap().pop_front() {
+			return Ok(route)
+		}
 		Err(msgs::LightningError {
 			err: String::from("Not implemented"),
 			action: msgs::ErrorAction::IgnoreError,
@@ -434,6 +440,29 @@ impl KeyProvider {
 	}
 }
 
+// Returns a bool indicating whether the payment failed.
+#[inline]
+fn check_payment_send_events(source: &ChanMan, amt: u64, min_sendable: u64, max_sendable: u64) -> bool {
+	let mut payment_failed = false;
+	let events = source.get_and_clear_pending_events();
+	assert!(events.len() == 2 || events.len() == 0);
+	for ev in events {
+		match ev {
+			events::Event::PaymentPathFailed { failure: events::PathFailure::InitialSend { err }, .. } => {
+				check_api_err(err, amt > max_sendable || amt < min_sendable);
+			},
+			events::Event::PaymentFailed { .. } => {},
+			_ => panic!()
+		};
+		payment_failed = true;
+	}
+	// Note that while the max is a strict upper-bound, we can occasionally send substantially
+	// below the minimum, with some gap which is unusable immediately below the minimum. Thus,
+	// we don't check against min_value_sendable here.
+	assert!(payment_failed || (amt <= max_sendable));
+	payment_failed
+}
+
 #[inline]
 fn check_api_err(api_err: APIError, sendable_bounds_violated: bool) {
 	match api_err {
@@ -460,34 +489,6 @@ fn check_api_err(api_err: APIError, sendable_bounds_violated: bool) {
 		},
 	}
 }
-#[inline]
-fn check_payment_err(send_err: PaymentSendFailure, sendable_bounds_violated: bool) {
-	match send_err {
-		PaymentSendFailure::ParameterError(api_err) => {
-			check_api_err(api_err, sendable_bounds_violated)
-		},
-		PaymentSendFailure::PathParameterError(per_path_results) => {
-			for res in per_path_results {
-				if let Err(api_err) = res {
-					check_api_err(api_err, sendable_bounds_violated);
-				}
-			}
-		},
-		PaymentSendFailure::AllFailedResendSafe(per_path_results) => {
-			for api_err in per_path_results {
-				check_api_err(api_err, sendable_bounds_violated);
-			}
-		},
-		PaymentSendFailure::PartialFailure { results, .. } => {
-			for res in results {
-				if let Err(api_err) = res {
-					check_api_err(api_err, sendable_bounds_violated);
-				}
-			}
-		},
-		PaymentSendFailure::DuplicatePayment => panic!(),
-	}
-}
 
 type ChanMan<'a> = ChannelManager<
 	Arc<TestChainMonitor>,
@@ -546,7 +547,8 @@ fn send_payment(
 		.find(|chan| chan.short_channel_id == Some(dest_chan_id))
 		.map(|chan| (chan.next_outbound_htlc_minimum_msat, chan.next_outbound_htlc_limit_msat))
 		.unwrap_or((0, 0));
-	if let Err(err) = source.send_payment_with_route(
+	let mut next_routes = source.router.next_routes.lock().unwrap();
+	next_routes.push_back(
 		Route {
 			paths: vec![Path {
 				hops: vec![RouteHop {
@@ -561,19 +563,21 @@ fn send_payment(
 				blinded_tail: None,
 			}],
 			route_params: None,
-		},
+		}
+	);
+	let route_params = RouteParameters::from_payment_params_and_value(
+		PaymentParameters::from_node_id(source.get_our_node_id(), TEST_FINAL_CLTV), amt
+	);
+	if let Err(err) = source.send_payment(
 		payment_hash,
 		RecipientOnionFields::secret_only(payment_secret),
 		PaymentId(payment_id),
+		route_params,
+		Retry::Attempts(0)
 	) {
-		check_payment_err(err, amt > max_value_sendable || amt < min_value_sendable);
-		false
+		panic!("Errored with {:?} on initial payment send", err);
 	} else {
-		// Note that while the max is a strict upper-bound, we can occasionally send substantially
-		// below the minimum, with some gap which is unusable immediately below the minimum. Thus,
-		// we don't check against min_value_sendable here.
-		assert!(amt <= max_value_sendable);
-		true
+		check_payment_send_events(source, amt, min_value_sendable, max_value_sendable)
 	}
 }
 
@@ -615,7 +619,8 @@ fn send_hop_payment(
 		.map(|chan| (chan.next_outbound_htlc_minimum_msat, chan.next_outbound_htlc_limit_msat))
 		.unwrap_or((0, 0));
 	let first_hop_fee = 50_000;
-	if let Err(err) = source.send_payment_with_route(
+	let mut next_routes = source.router.next_routes.lock().unwrap();
+	next_routes.push_back(
 		Route {
 			paths: vec![Path {
 				hops: vec![
@@ -641,28 +646,30 @@ fn send_hop_payment(
 				blinded_tail: None,
 			}],
 			route_params: None,
-		},
+		}
+	);
+	let route_params = RouteParameters::from_payment_params_and_value(
+		PaymentParameters::from_node_id(source.get_our_node_id(), TEST_FINAL_CLTV), amt
+	);
+	if let Err(err) = source.send_payment(
 		payment_hash,
 		RecipientOnionFields::secret_only(payment_secret),
 		PaymentId(payment_id),
+		route_params,
+		Retry::Attempts(0)
 	) {
-		let sent_amt = amt + first_hop_fee;
-		check_payment_err(err, sent_amt < min_value_sendable || sent_amt > max_value_sendable);
-		false
+		panic!("Errored with {:?} on initial payment send", err);
 	} else {
-		// Note that while the max is a strict upper-bound, we can occasionally send substantially
-		// below the minimum, with some gap which is unusable immediately below the minimum. Thus,
-		// we don't check against min_value_sendable here.
-		assert!(amt + first_hop_fee <= max_value_sendable);
-		true
+		let sent_amt = amt + first_hop_fee;
+		check_payment_send_events(source, sent_amt, min_value_sendable, max_value_sendable)
 	}
 }
 
 #[inline]
 pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 	let out = SearchingOutput::new(underlying_out);
 	let broadcast = Arc::new(TestBroadcaster {});
-	let router = FuzzRouter {};
+	let router = FuzzRouter { next_routes: Mutex::new(VecDeque::new()) };
 
 	macro_rules! make_node {
 		($node_id: expr, $fee_estimator: expr) => {{

lightning/src/ln/channelmanager.rs

@@ -125,7 +125,9 @@ use core::time::Duration;
 use core::ops::Deref;
 use bitcoin::hex::impl_fmt_traits;
 // Re-export this for use in the public API.
-pub use crate::ln::outbound_payment::{Bolt12PaymentError, PaymentSendFailure, ProbeSendFailure, Retry, RetryableSendFailure, RecipientOnionFields};
+pub use crate::ln::outbound_payment::{Bolt12PaymentError, ProbeSendFailure, Retry, RetryableSendFailure, RecipientOnionFields};
+#[cfg(test)]
+pub(crate) use crate::ln::outbound_payment::PaymentSendFailure;
 use crate::ln::script::ShutdownScript;
 
 // We hold various information about HTLC relay in the HTLC objects in Channel itself:
@@ -2363,7 +2365,9 @@ where
 	fee_estimator: LowerBoundedFeeEstimator<F>,
 	chain_monitor: M,
 	tx_broadcaster: T,
-	#[allow(unused)]
+	#[cfg(fuzzing)]
+	pub router: R,
+	#[cfg(not(fuzzing))]
 	router: R,
 	message_router: MR,
 
@@ -4525,8 +4529,11 @@ where
 	// [`TestRouter::expect_find_route`] instead.
 	//
 	// [`TestRouter::expect_find_route`]: crate::util::test_utils::TestRouter::expect_find_route
-	#[cfg(any(test, fuzzing))]
-	pub fn send_payment_with_route(&self, route: Route, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields, payment_id: PaymentId) -> Result<(), PaymentSendFailure> {
+	#[cfg(test)]
+	pub(crate) fn send_payment_with_route(
+		&self, route: Route, payment_hash: PaymentHash, recipient_onion: RecipientOnionFields,
+		payment_id: PaymentId
+	) -> Result<(), PaymentSendFailure> {
 		let best_block_height = self.best_block.read().unwrap().height;
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
 		self.pending_outbound_payments

lightning/src/ln/outbound_payment.rs

@@ -482,7 +482,7 @@ pub enum RetryableSendFailure {
 /// as the Err() type describing which state the payment is in, see the description of individual
 /// enum states for more.
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub enum PaymentSendFailure {
+pub(crate) enum PaymentSendFailure {
 	/// A parameter which was passed to send_payment was invalid, preventing us from attempting to
 	/// send the payment at all.
 	///