add the bolt12 invoice to the PaymentSend event

To enable proof of payment, we need to share the bolt12 invoice with the library user.

This is already possible if we `manually_handle_bolt12_invoices`, but
this approach requires a significant amount of work from the user.

This commit adds the bolt12 invoice to the PaymentSend event when
the payment is completed. This allows the user to always have the option to
perform proof of payment.

Link: #3344
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

Author: vincenzopalazzo

lightning/src/events/mod.rs

@@ -939,6 +939,8 @@ pub enum Event {
 		///
 		/// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
 		fee_paid_msat: Option<u64>,
+		/// The bolt12 invoice that was paid. `None` if the payment was a non-bolt12 payment.
+		bolt12_invoice: Option<Bolt12Invoice>,
 	},
 	/// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
 	/// provide failure information for each path attempt in the payment, including retries.
@@ -1190,12 +1192,12 @@ pub enum Event {
 		/// events generated or serialized by versions prior to 0.0.122.
 		next_user_channel_id: Option<u128>,
 		/// The node id of the previous node.
-		/// 
+		///
 		/// This is only `None` for HTLCs received prior to 0.1 or for events serialized by
 		/// versions prior to 0.1
 		prev_node_id: Option<PublicKey>,
 		/// The node id of the next node.
-		/// 
+		///
 		/// This is only `None` for HTLCs received prior to 0.1 or for events serialized by
 		/// versions prior to 0.1
 		next_node_id: Option<PublicKey>,
@@ -1546,13 +1548,14 @@ impl Writeable for Event {
 					(13, payment_id, option),
 				});
 			},
-			&Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
+			&Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat, ref bolt12_invoice } => {
 				2u8.write(writer)?;
 				write_tlv_fields!(writer, {
 					(0, payment_preimage, required),
 					(1, payment_hash, required),
 					(3, payment_id, option),
 					(5, fee_paid_msat, option),
+					(7, bolt12_invoice, option),
 				});
 			},
 			&Event::PaymentPathFailed {
@@ -1886,11 +1889,13 @@ impl MaybeReadable for Event {
 					let mut payment_hash = None;
 					let mut payment_id = None;
 					let mut fee_paid_msat = None;
+					let mut bolt12_invoice = None;
 					read_tlv_fields!(reader, {
 						(0, payment_preimage, required),
 						(1, payment_hash, option),
 						(3, payment_id, option),
 						(5, fee_paid_msat, option),
+						(7, bolt12_invoice, option),
 					});
 					if payment_hash.is_none() {
 						payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).to_byte_array()));
@@ -1900,6 +1905,7 @@ impl MaybeReadable for Event {
 						payment_preimage,
 						payment_hash: payment_hash.unwrap(),
 						fee_paid_msat,
+						bolt12_invoice,
 					}))
 				};
 				f()

lightning/src/ln/functional_test_utils.rs

@@ -37,6 +37,7 @@ use crate::util::test_channel_signer::SignerOp;
 use crate::util::test_utils;
 use crate::util::test_utils::{TestChainMonitor, TestScorer, TestKeysInterface};
 use crate::util::ser::{ReadableArgs, Writeable};
+use crate::offers::invoice::Bolt12Invoice;
 
 use bitcoin::WPubkeyHash;
 use bitcoin::amount::Amount;
@@ -3093,10 +3094,11 @@ pub fn claim_payment_along_route(args: ClaimAlongRouteArgs) {
 	}
 }
 
-pub fn claim_payment<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expected_route: &[&Node<'a, 'b, 'c>], our_payment_preimage: PaymentPreimage) {
+pub fn claim_payment<'a, 'b, 'c>(origin_node: &Node<'a, 'b, 'c>, expected_route: &[&Node<'a, 'b, 'c>], our_payment_preimage: PaymentPreimage) -> Option<Bolt12Invoice> {
 	claim_payment_along_route(
 		ClaimAlongRouteArgs::new(origin_node, &[expected_route], our_payment_preimage)
 	);
+	None
 }
 
 pub const TEST_FINAL_CLTV: u32 = 70;

lightning/src/ln/offers_tests.rs

@@ -168,7 +168,7 @@ fn route_bolt12_payment<'a, 'b, 'c>(
 }
 
 fn claim_bolt12_payment<'a, 'b, 'c>(
-	node: &Node<'a, 'b, 'c>, path: &[&Node<'a, 'b, 'c>], expected_payment_context: PaymentContext
+	node: &Node<'a, 'b, 'c>, path: &[&Node<'a, 'b, 'c>], expected_payment_context: PaymentContext, invoice: &Bolt12Invoice
 ) {
 	let recipient = &path[path.len() - 1];
 	let payment_purpose = match get_event!(recipient, Event::PaymentClaimable) {
@@ -188,7 +188,10 @@ fn claim_bolt12_payment<'a, 'b, 'c>(
 		},
 		_ => panic!("Unexpected payment purpose: {:?}", payment_purpose),
 	}
-	claim_payment(node, path, payment_preimage);
+	let Some(inv) = claim_payment(node, path, payment_preimage) else {
+		return;
+	};
+	assert_eq!(inv, invoice.to_owned());
 }
 
 fn extract_offer_nonce<'a, 'b, 'c>(node: &Node<'a, 'b, 'c>, message: &OnionMessage) -> Nonce {
@@ -597,7 +600,7 @@ fn creates_and_pays_for_offer_using_two_hop_blinded_path() {
 	route_bolt12_payment(david, &[charlie, bob, alice], &invoice);
 	expect_recent_payment!(david, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context);
+	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context, &invoice);
 	expect_recent_payment!(david, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -680,7 +683,7 @@ fn creates_and_pays_for_refund_using_two_hop_blinded_path() {
 	route_bolt12_payment(david, &[charlie, bob, alice], &invoice);
 	expect_recent_payment!(david, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context);
+	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context, &invoice);
 	expect_recent_payment!(david, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -747,7 +750,7 @@ fn creates_and_pays_for_offer_using_one_hop_blinded_path() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -803,7 +806,7 @@ fn creates_and_pays_for_refund_using_one_hop_blinded_path() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -857,7 +860,7 @@ fn pays_for_offer_without_blinded_paths() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -900,7 +903,7 @@ fn pays_for_refund_without_blinded_paths() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -1138,7 +1141,7 @@ fn creates_and_pays_for_offer_with_retry() {
 	}
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -1209,7 +1212,7 @@ fn pays_bolt12_invoice_asynchronously() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 
 	assert_eq!(
@@ -1289,7 +1292,7 @@ fn creates_offer_with_blinded_path_using_unannounced_introduction_node() {
 	route_bolt12_payment(bob, &[alice], &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);
 
-	claim_bolt12_payment(bob, &[alice], payment_context);
+	claim_bolt12_payment(bob, &[alice], payment_context, &invoice);
 	expect_recent_payment!(bob, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -2145,7 +2148,7 @@ fn fails_paying_invoice_more_than_once() {
 	assert!(david.node.get_and_clear_pending_msg_events().is_empty());
 
 	// Complete paying the first invoice
-	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context);
+	claim_bolt12_payment(david, &[charlie, bob, alice], payment_context, &invoice1);
 	expect_recent_payment!(david, RecentPaymentDetails::Fulfilled, payment_id);
 }
 
@@ -2405,4 +2408,3 @@ fn no_double_pay_with_stale_channelmanager() {
 	// generated in response to the duplicate invoice.
 	assert!(nodes[0].node.get_and_clear_pending_events().is_empty());
 }
-

lightning/src/ln/outbound_payment.rs

@@ -1947,6 +1947,7 @@ impl OutboundPayments {
 					payment_preimage,
 					payment_hash,
 					fee_paid_msat,
+					bolt12_invoice: payment.get().bolt12_invoice().cloned(),
 				}, Some(ev_completion_action.clone())));
 				payment.get_mut().mark_fulfilled();
 			}