Return the invoice when requesting a refund

When sending an invoice for a refund, information from the invoice may
be useful for caller. For instance, the payment_hash can be used to
track whether the refund was paid. Return the invoice to facilitate this
use case.

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 210515236342303576f6ae373d6788d697b75eed..553ff853e7ef26b2f8494807b0e0fb14505d5cac 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -1694,15 +1694,20 @@ where
 /// #
 /// # fn example<T: AChannelManager>(channel_manager: T, refund: &Refund) {
 /// # let channel_manager = channel_manager.get_cm();
-/// match channel_manager.request_refund_payment(refund) {
-///     Ok(()) => println!("Requesting payment for refund"),
-///     Err(e) => println!("Unable to request payment for refund: {:?}", e),
-/// }
+/// let known_payment_hash = match channel_manager.request_refund_payment(refund) {
+///     Ok(invoice) => {
+///         let payment_hash = invoice.payment_hash();
+///         println!("Requesting refund payment {}", payment_hash);
+///         payment_hash
+///     },
+///     Err(e) => panic!("Unable to request payment for refund: {:?}", e),
+/// };
 ///
 /// // On the event processing thread
 /// channel_manager.process_pending_events(&|event| match event {
 ///     Event::PaymentClaimable { payment_hash, purpose, .. } => match purpose {
 ///            PaymentPurpose::InvoicePayment { payment_preimage: Some(payment_preimage), .. } => {
+///             assert_eq!(payment_hash, known_payment_hash);
 ///             println!("Claiming payment {}", payment_hash);
 ///             channel_manager.claim_funds(payment_preimage);
 ///         },
@@ -1713,6 +1718,7 @@ where
 /// #         _ => {},
 ///     },
 ///     Event::PaymentClaimed { payment_hash, amount_msat, .. } => {
+///         assert_eq!(payment_hash, known_payment_hash);
 ///         println!("Claimed {} msats", amount_msat);
 ///     },
 ///     // ...
@@ -8774,7 +8780,7 @@ where
        ///
        /// The resulting invoice uses a [`PaymentHash`] recognized by the [`ChannelManager`] and a
        /// [`BlindedPath`] containing the [`PaymentSecret`] needed to reconstruct the corresponding
-       /// [`PaymentPreimage`].
+       /// [`PaymentPreimage`]. It is returned purely for informational purposes.
        ///
        /// # Limitations
        ///
@@ -8791,7 +8797,9 @@ where
        ///   the invoice.
        ///
        /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
-       pub fn request_refund_payment(&self, refund: &Refund) -> Result<(), Bolt12SemanticError> {
+       pub fn request_refund_payment(
+               &self, refund: &Refund
+       ) -> Result<Bolt12Invoice, Bolt12SemanticError> {
                let expanded_key = &self.inbound_payment_key;
                let entropy = &*self.entropy_source;
                let secp_ctx = &self.secp_ctx;
@@ -8830,7 +8838,7 @@ where
                                let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();
                                if refund.paths().is_empty() {
                                        let message = new_pending_onion_message(
-                                               OffersMessage::Invoice(invoice),
+                                               OffersMessage::Invoice(invoice.clone()),
                                                Destination::Node(refund.payer_id()),
                                                Some(reply_path),
                                        );
@@ -8846,7 +8854,7 @@ where
                                        }
                                }
 
-                               Ok(())
+                               Ok(invoice)
                        },
                        Err(()) => Err(Bolt12SemanticError::InvalidAmount),
                }

diff --git a/lightning/src/ln/offers_tests.rs b/lightning/src/ln/offers_tests.rs
index 4c8c1ecba038568d1fc690b8a18f1adfce0e6d56..5b774ce4ee266e597f4d43a534cb52a8300d3119 100644 (file)
--- a/lightning/src/ln/offers_tests.rs
+++ b/lightning/src/ln/offers_tests.rs
@@ -473,7 +473,7 @@ fn creates_and_pays_for_refund_using_two_hop_blinded_path() {
        }
        expect_recent_payment!(david, RecentPaymentDetails::AwaitingInvoice, payment_id);
 
-       alice.node.request_refund_payment(&refund).unwrap();
+       let expected_invoice = alice.node.request_refund_payment(&refund).unwrap();
 
        connect_peers(alice, charlie);
 
@@ -484,6 +484,8 @@ fn creates_and_pays_for_refund_using_two_hop_blinded_path() {
        david.onion_messenger.handle_onion_message(&charlie_id, &onion_message);
 
        let invoice = extract_invoice(david, &onion_message);
+       assert_eq!(invoice, expected_invoice);
+
        assert_eq!(invoice.amount_msats(), 10_000_000);
        assert_ne!(invoice.signing_pubkey(), alice_id);
        assert!(!invoice.payment_paths().is_empty());
@@ -589,12 +591,14 @@ fn creates_and_pays_for_refund_using_one_hop_blinded_path() {
        }
        expect_recent_payment!(bob, RecentPaymentDetails::AwaitingInvoice, payment_id);
 
-       alice.node.request_refund_payment(&refund).unwrap();
+       let expected_invoice = alice.node.request_refund_payment(&refund).unwrap();
 
        let onion_message = alice.onion_messenger.next_onion_message_for_peer(bob_id).unwrap();
        bob.onion_messenger.handle_onion_message(&alice_id, &onion_message);
 
        let invoice = extract_invoice(bob, &onion_message);
+       assert_eq!(invoice, expected_invoice);
+
        assert_eq!(invoice.amount_msats(), 10_000_000);
        assert_ne!(invoice.signing_pubkey(), alice_id);
        assert!(!invoice.payment_paths().is_empty());
@@ -681,12 +685,14 @@ fn pays_for_refund_without_blinded_paths() {
        assert!(refund.paths().is_empty());
        expect_recent_payment!(bob, RecentPaymentDetails::AwaitingInvoice, payment_id);
 
-       alice.node.request_refund_payment(&refund).unwrap();
+       let expected_invoice = alice.node.request_refund_payment(&refund).unwrap();
 
        let onion_message = alice.onion_messenger.next_onion_message_for_peer(bob_id).unwrap();
        bob.onion_messenger.handle_onion_message(&alice_id, &onion_message);
 
        let invoice = extract_invoice(bob, &onion_message);
+       assert_eq!(invoice, expected_invoice);
+
        route_bolt12_payment(bob, &[alice], &invoice);
        expect_recent_payment!(bob, RecentPaymentDetails::Pending, payment_id);