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 BOLTs PR 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.

Author: valentinewallace

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>,
@@ -1004,7 +1005,7 @@ 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, ..
 				} => {
@@ -1048,6 +1049,11 @@ impl OutboundPayments {
 						keysend_preimage,
 						retry_strategy: *retry_strategy,
 						route_params,
+						invoice_request:
+							retryable_invoice_request
+							.take()
+							.ok_or(Bolt12PaymentError::UnexpectedInvoice)?
+							.invoice_request,
 					};
 					return Ok(())
 				},
@@ -2256,6 +2262,7 @@ impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
 		(2, keysend_preimage, required),
 		(4, retry_strategy, required),
 		(6, route_params, required),
+		(8, invoice_request, required),
 	},
 );
 
@@ -2270,15 +2277,19 @@ mod tests {
 	use crate::events::{Event, PathFailure, PaymentFailureReason};
 	use crate::types::payment::{PaymentHash, PaymentPreimage};
 	use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+	use crate::ln::inbound_payment::ExpandedKey;
 	use crate::types::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::nonce::Nonce;
 	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::sign::KeyMaterial;
 	use crate::sync::{Arc, Mutex, RwLock};
 	use crate::util::errors::APIError;
 	use crate::util::hash_tables::new_hash_map;
@@ -2823,6 +2834,22 @@ mod tests {
 		assert!(pending_events.lock().unwrap().is_empty());
 	}
 
+	fn dummy_invoice_request() -> InvoiceRequest {
+		let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
+		let entropy = FixedEntropy {};
+		let nonce = Nonce::from_entropy_source(&entropy);
+		let secp_ctx = Secp256k1::new();
+		let payment_id = PaymentId([1; 32]);
+
+		OfferBuilder::new(recipient_pubkey())
+			.amount_msats(1000)
+			.build().unwrap()
+			.request_invoice_deriving_signing_pubkey(&expanded_key, nonce, &secp_ctx, payment_id)
+			.unwrap()
+			.build_and_sign()
+			.unwrap()
+	}
+
 	#[test]
 	fn time_out_unreleased_async_payments() {
 		let pending_events = Mutex::new(VecDeque::new());
@@ -2844,6 +2871,7 @@ mod tests {
 			keysend_preimage: PaymentPreimage([0; 32]),
 			retry_strategy: Retry::Attempts(0),
 			route_params,
+			invoice_request: dummy_invoice_request(),
 		};
 		outbounds.insert(payment_id, outbound);
 		core::mem::drop(outbounds);
@@ -2890,6 +2918,7 @@ mod tests {
 			keysend_preimage: PaymentPreimage([0; 32]),
 			retry_strategy: Retry::Attempts(0),
 			route_params,
+			invoice_request: dummy_invoice_request(),
 		};
 		outbounds.insert(payment_id, outbound);
 		core::mem::drop(outbounds);