Store invreqs in StaticInvoiceReceived outbound payments

When transitioning outbound payments from AwaitingInvoice to
StaticInvoiceReceived, include the invreq in the new state's outbound payment
storage for future inclusion in an async payment onion.

Per <lightning/bolts#1149>, when paying a static
invoice we need to include our original invoice request in the HTLC onion since
the recipient wouldn't have received it previously.

lightning/src/ln/outbound_payment.rs

@@ -83,6 +83,7 @@ pub(crate) enum PendingOutboundPayment {
 		keysend_preimage: PaymentPreimage,
 		retry_strategy: Retry,
 		route_params: RouteParameters,
+		invoice_request: InvoiceRequest,
 	},
 	Retryable {
 		retry_strategy: Option<Retry>,
@@ -1003,7 +1004,7 @@ impl OutboundPayments {
 		}
 
 		match self.pending_outbound_payments.lock().unwrap().entry(payment_id) {
-			hash_map::Entry::Occupied(mut entry) => match entry.get() {
+			hash_map::Entry::Occupied(mut entry) => match entry.get_mut() {
 				PendingOutboundPayment::AwaitingInvoice {
 					retry_strategy, retryable_invoice_request, max_total_routing_fee_msat, ..
 				} => {
@@ -1047,6 +1048,11 @@ impl OutboundPayments {
 						keysend_preimage,
 						retry_strategy: *retry_strategy,
 						route_params,
+						invoice_request:
+							retryable_invoice_request
+							.take()
+							.ok_or(Bolt12PaymentError::UnexpectedInvoice)?
+							.invoice_request,
 					};
 					return Ok(())
 				},
@@ -2250,32 +2256,37 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
 		(2, keysend_preimage, required),
 		(4, retry_strategy, required),
 		(6, route_params, required),
+		(8, invoice_request, required),
 	},
 );
 
 #[cfg(test)]
 mod tests {
+	use bitcoin::hex::FromHex;
 	use bitcoin::network::Network;
 	use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
 
 	use core::time::Duration;
 
 	use crate::blinded_path::EmptyNodeIdLookUp;
 	use crate::events::{Event, PathFailure, PaymentFailureReason};
+	use crate::io::Cursor;
 	use crate::ln::types::{PaymentHash, PaymentPreimage};
 	use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
 	use crate::ln::features::{Bolt12InvoiceFeatures, ChannelFeatures, NodeFeatures};
 	use crate::ln::msgs::{ErrorAction, LightningError};
 	use crate::ln::outbound_payment::{Bolt12PaymentError, OutboundPayments, PendingOutboundPayment, Retry, RetryableSendFailure, StaleExpiration};
 	#[cfg(feature = "std")]
 	use crate::offers::invoice::DEFAULT_RELATIVE_EXPIRY;
+	use crate::offers::invoice_request::InvoiceRequest;
 	use crate::offers::offer::OfferBuilder;
 	use crate::offers::test_utils::*;
 	use crate::routing::gossip::NetworkGraph;
 	use crate::routing::router::{InFlightHtlcs, Path, PaymentParameters, Route, RouteHop, RouteParameters};
 	use crate::sync::{Arc, Mutex, RwLock};
 	use crate::util::errors::APIError;
 	use crate::util::hash_tables::new_hash_map;
+	use crate::util::ser::Readable;
 	use crate::util::test_utils;
 
 	use alloc::collections::VecDeque;
@@ -2817,6 +2828,11 @@ mod tests {
 		assert!(pending_events.lock().unwrap().is_empty());
 	}
 
+	fn invoice_request() -> InvoiceRequest {
+		let invreq_bytes = <Vec<u8>>::from_hex("00200101010101010101010101010101010101010101010101010101010101010101080203e80a00162102bb58b5feca505c74edc000d8282fc556e51a1024fc8e7d7e56c6f887c5c8d5f25821035be5e9478209674a96e60f1f037f6176540fd001fa1d64694770c56a7709c42cf040a31d68198578a5aa1fe57de5f6d33f89c1556752cb333dbb56ac727f751893804d3a26b42909f1952fb1db8080238f9476b829160387692df35ff85dfe72e2ed").unwrap();
+		Readable::read(&mut Cursor::new(&invreq_bytes[..])).unwrap()
+	}
+
 	#[test]
 	fn time_out_unreleased_async_payments() {
 		let pending_events = Mutex::new(VecDeque::new());
@@ -2838,6 +2854,7 @@ mod tests {
 			keysend_preimage: PaymentPreimage([0; 32]),
 			retry_strategy: Retry::Attempts(0),
 			route_params,
+			invoice_request: invoice_request(),
 		};
 		outbounds.insert(payment_id, outbound);
 		core::mem::drop(outbounds);
@@ -2884,6 +2901,7 @@ mod tests {
 			keysend_preimage: PaymentPreimage([0; 32]),
 			retry_strategy: Retry::Attempts(0),
 			route_params,
+			invoice_request: invoice_request(),
 		};
 		outbounds.insert(payment_id, outbound);
 		core::mem::drop(outbounds);