Remove PaymentContext from OnionPayload

PaymentContext is already stored in ClaimablePayment via PaymentPurpose,
so there is no need to repeat it in each ClaimableHTLC via OnionPayload.
This avoids cloning the PaymentContext each time an HTLC is received,
other than for the first HTLC for a payment.

Author: jkczyz

lightning/src/ln/channelmanager.rs

@@ -357,11 +357,6 @@ enum OnionPayload {
 		/// This is only here for backwards-compatibility in serialization, in the future it can be
 		/// removed, breaking clients running 0.0.106 and earlier.
 		_legacy_hop_data: Option<msgs::FinalOnionHopData>,
-		/// The context of the payment included by the recipient in a blinded path, or `None` if a
-		/// blinded path was not used.
-		///
-		/// Used in part to determine the [`events::PaymentPurpose`].
-		payment_context: Option<PaymentContext>,
 	},
 	/// Contains the payer-provided preimage.
 	Spontaneous(PaymentPreimage),
@@ -5346,7 +5341,7 @@ where
 								}
 							}) => {
 								let blinded_failure = routing.blinded_failure();
-								let (cltv_expiry, onion_payload, payment_data, phantom_shared_secret, mut onion_fields) = match routing {
+								let (cltv_expiry, onion_payload, payment_data, payment_context, phantom_shared_secret, mut onion_fields) = match routing {
 									PendingHTLCRouting::Receive {
 										payment_data, payment_metadata, payment_context,
 										incoming_cltv_expiry, phantom_shared_secret, custom_tlvs,
@@ -5355,8 +5350,8 @@ where
 										let _legacy_hop_data = Some(payment_data.clone());
 										let onion_fields = RecipientOnionFields { payment_secret: Some(payment_data.payment_secret),
 												payment_metadata, custom_tlvs };
-										(incoming_cltv_expiry, OnionPayload::Invoice { _legacy_hop_data, payment_context },
-											Some(payment_data), phantom_shared_secret, onion_fields)
+										(incoming_cltv_expiry, OnionPayload::Invoice { _legacy_hop_data },
+											Some(payment_data), payment_context, phantom_shared_secret, onion_fields)
 									},
 									PendingHTLCRouting::ReceiveKeysend {
 										payment_data, payment_preimage, payment_metadata,
@@ -5368,7 +5363,7 @@ where
 											custom_tlvs,
 										};
 										(incoming_cltv_expiry, OnionPayload::Spontaneous(payment_preimage),
-											payment_data, None, onion_fields)
+											payment_data, None, None, onion_fields)
 									},
 									_ => {
 										panic!("short_channel_id == 0 should imply any pending_forward entries are of type Receive");
@@ -5530,7 +5525,7 @@ where
 								match payment_secrets.entry(payment_hash) {
 									hash_map::Entry::Vacant(_) => {
 										match claimable_htlc.onion_payload {
-											OnionPayload::Invoice { ref payment_context, .. } => {
+											OnionPayload::Invoice { .. } => {
 												let payment_data = payment_data.unwrap();
 												let (payment_preimage, min_final_cltv_expiry_delta) = match inbound_payment::verify(payment_hash, &payment_data, self.highest_seen_timestamp.load(Ordering::Acquire) as u64, &self.inbound_payment_key, &self.logger) {
 													Ok(result) => result,
@@ -5550,7 +5545,7 @@ where
 												let purpose = events::PaymentPurpose::from_parts(
 													payment_preimage,
 													payment_data.payment_secret,
-													payment_context.clone(),
+													payment_context,
 												);
 												check_total_value!(purpose);
 											},
@@ -5561,13 +5556,10 @@ where
 										}
 									},
 									hash_map::Entry::Occupied(inbound_payment) => {
-										let payment_context = match claimable_htlc.onion_payload {
-											OnionPayload::Spontaneous(_) => {
-												log_trace!(self.logger, "Failing new keysend HTLC with payment_hash {} because we already have an inbound payment with the same payment hash", &payment_hash);
-												fail_htlc!(claimable_htlc, payment_hash);
-											},
-											OnionPayload::Invoice { ref payment_context, .. } => payment_context,
-										};
+										if let OnionPayload::Spontaneous(_) = claimable_htlc.onion_payload {
+											log_trace!(self.logger, "Failing new keysend HTLC with payment_hash {} because we already have an inbound payment with the same payment hash", &payment_hash);
+											fail_htlc!(claimable_htlc, payment_hash);
+										}
 										let payment_data = payment_data.unwrap();
 										if inbound_payment.get().payment_secret != payment_data.payment_secret {
 											log_trace!(self.logger, "Failing new HTLC with payment_hash {} as it didn't match our expected payment secret.", &payment_hash);
@@ -5580,7 +5572,7 @@ where
 											let purpose = events::PaymentPurpose::from_parts(
 												inbound_payment.get().payment_preimage,
 												payment_data.payment_secret,
-												payment_context.clone(),
+												payment_context,
 											);
 											let payment_claimable_generated = check_total_value!(purpose);
 											if payment_claimable_generated {
@@ -10815,11 +10807,11 @@ impl_writeable_tlv_based!(HTLCPreviousHopData, {
 
 impl Writeable for ClaimableHTLC {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
-		let (payment_data, keysend_preimage, payment_context) = match &self.onion_payload {
-			OnionPayload::Invoice { _legacy_hop_data, payment_context } => {
-				(_legacy_hop_data.as_ref(), None, payment_context.as_ref())
+		let (payment_data, keysend_preimage) = match &self.onion_payload {
+			OnionPayload::Invoice { _legacy_hop_data } => {
+				(_legacy_hop_data.as_ref(), None)
 			},
-			OnionPayload::Spontaneous(preimage) => (None, Some(preimage), None),
+			OnionPayload::Spontaneous(preimage) => (None, Some(preimage)),
 		};
 		write_tlv_fields!(writer, {
 			(0, self.prev_hop, required),
@@ -10831,7 +10823,6 @@ impl Writeable for ClaimableHTLC {
 			(6, self.cltv_expiry, required),
 			(8, keysend_preimage, option),
 			(10, self.counterparty_skimmed_fee_msat, option),
-			(11, payment_context, option),
 		});
 		Ok(())
 	}
@@ -10849,7 +10840,6 @@ impl Readable for ClaimableHTLC {
 			(6, cltv_expiry, required),
 			(8, keysend_preimage, option),
 			(10, counterparty_skimmed_fee_msat, option),
-			(11, payment_context, option),
 		});
 		let payment_data: Option<msgs::FinalOnionHopData> = payment_data_opt;
 		let value = value_ser.0.unwrap();
@@ -10870,7 +10860,7 @@ impl Readable for ClaimableHTLC {
 					}
 					total_msat = Some(payment_data.as_ref().unwrap().total_msat);
 				}
-				OnionPayload::Invoice { _legacy_hop_data: payment_data, payment_context }
+				OnionPayload::Invoice { _legacy_hop_data: payment_data }
 			},
 		};
 		Ok(Self {
@@ -12106,7 +12096,7 @@ where
 					return Err(DecodeError::InvalidValue);
 				}
 				let purpose = match &htlcs[0].onion_payload {
-					OnionPayload::Invoice { _legacy_hop_data, payment_context: _ } => {
+					OnionPayload::Invoice { _legacy_hop_data } => {
 						if let Some(hop_data) = _legacy_hop_data {
 							events::PaymentPurpose::Bolt11InvoicePayment {
 								payment_preimage: match pending_inbound_payments.get(&payment_hash) {