From c9c674fe976f4f9f9b73c464756a69048d5539f7 Mon Sep 17 00:00:00 2001
From: 21M4TW <21m4tw@proton.me>
Date: Tue, 15 Apr 2025 08:49:34 -0400
Subject: [PATCH] -Fixing offers when offer_paths are present and
 offer_issuer_id is no longer needed. -There is a missing piece however in
 plugins/offers_invreq_hook.c, which causes an error in plugins/fetchinvoice.c
 when trying to fetch an invoice for an offer without offer_issuer _id.
 Comments were added to describe the remaining issue.

---
 plugins/fetchinvoice.c       | 5 +++++
 plugins/offers_invreq_hook.c | 5 +++++
 plugins/offers_offer.c       | 6 ++++++
 3 files changed, 16 insertions(+)

diff --git a/plugins/fetchinvoice.c b/plugins/fetchinvoice.c
index c40889763d95..e566101cc19c 100644
--- a/plugins/fetchinvoice.c
+++ b/plugins/fetchinvoice.c
@@ -240,6 +240,11 @@ static struct command_result *handle_invreq_response(struct command *cmd,
 		badfield = "invoice_payment_hash";
 		goto badinv;
 	}
+	/* Currently the following check fails for offers that do not contain
+	 * offer_issuer_id and for which an invoice is fetched from a CLN node,
+	 * because listoffers_done in offers_invrek_hook.c sets invoice_node_id
+	 * to offer_issuer_id regardless.
+	 */
 	if (!inv->invoice_node_id) {
 		badfield = "invoice_node_id";
 		goto badinv;
diff --git a/plugins/offers_invreq_hook.c b/plugins/offers_invreq_hook.c
index 5cefec997537..2a94214780b2 100644
--- a/plugins/offers_invreq_hook.c
+++ b/plugins/offers_invreq_hook.c
@@ -935,6 +935,11 @@ static struct command_result *listoffers_done(struct command *cmd,
 	 *     - MUST set `invoice_node_id` to the `offer_issuer_id`
 	 */
 	/* FIXME: We always provide an offer_issuer_id! */
+	/* The following line is wrong when offer_issuer_id is not used.
+	 * According to fetchinvoice.c, it should be "equal to the final
+	 * `blinded_node_id` it [the payer] sent the invoice request to", when
+	 * offer_issuer_id is not set and offer_paths is set
+	 */
 	ir->inv->invoice_node_id = ir->inv->offer_issuer_id;
 
 	/* BOLT #12:
diff --git a/plugins/offers_offer.c b/plugins/offers_offer.c
index a50052cb13b1..ab9b42d206c6 100644
--- a/plugins/offers_offer.c
+++ b/plugins/offers_offer.c
@@ -296,6 +296,12 @@ static struct command_result *found_best_peer(struct command *cmd,
 		struct secret blinding_path_secret;
 		struct sha256 offer_id;
 
+		/* offer_issuer_id is not needed when offer_paths are used.
+		 * The following line seems to produce a valid offer with
+		 * offer_issuer_id removed.
+		 */
+		offinfo->offer->offer_issuer_id = NULL;
+
 		/* Note: "id" of offer minus paths */
 		offer_offer_id(offinfo->offer, &offer_id);