From: shaavan <shaavan.github@gmail.com>
Date: Fri, 6 Sep 2024 12:21:37 +0000 (+0530)
Subject: Add reply_path to BOLT12Invoices in Offers Flow
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=a4bf93610109c907a4a368069b3d0ace2604b602;p=rust-lightning

Add reply_path to BOLT12Invoices in Offers Flow

1. Introduced reply_path in BOLT12Invoices to address a gap in error handling.
   Previously, if a BOLT12Invoice sent in the offers flow generated an Invoice Error,
   the payer had no way to send this error back to the payee.
2. By adding a reply_path to the Invoice Message, the payer can now communicate
   any errors back to the payee, ensuring better error handling and communication
   within the offers flow.
---

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index c8597f8f0..993a320d1 100644
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -10927,7 +10927,12 @@ where
 				};
 
 				match response {
-					Ok(invoice) => Some((OffersMessage::Invoice(invoice), responder.respond())),
+					Ok(invoice) => {
+						let nonce = Nonce::from_entropy_source(&*self.entropy_source);
+						let hmac = payment_hash.hmac_for_offer_payment(nonce, expanded_key);
+						let context = MessageContext::Offers(OffersContext::InboundPayment { payment_hash, nonce, hmac });
+						Some((OffersMessage::Invoice(invoice), responder.respond_with_reply_path(context)))
+					},
 					Err(error) => Some((OffersMessage::InvoiceError(error.into()), responder.respond())),
 				}
 			},