f specify default channel_id for HTLCPreviousHopData & HTLCAddHTLCInfo

lightning/src/ln/channelmanager.rs

@@ -9664,7 +9664,9 @@ impl_writeable_tlv_based!(HTLCPreviousHopData, {
 	(4, htlc_id, required),
 	(6, incoming_packet_shared_secret, required),
 	(7, user_channel_id, option),
-	(8, channel_id, required),
+	// Note that by the time we get past the required read for type 2 above, outpoint will be
+	// filled in, so we can safely unwrap it here.
+	(9, channel_id, (default_value, ChannelId::v1_from_funding_outpoint(outpoint.0.unwrap()))),
 });
 
 impl Writeable for ClaimableHTLC {
@@ -9816,7 +9818,9 @@ impl_writeable_tlv_based!(PendingAddHTLCInfo, {
 	(2, prev_short_channel_id, required),
 	(4, prev_htlc_id, required),
 	(6, prev_funding_outpoint, required),
-	(8, prev_channel_id, required),
+	// Note that by the time we get past the required read for type 2 above, prev_funding_outpoint will be
+	// filled in, so we can safely unwrap it here.
+	(7, prev_channel_id, (default_value, ChannelId::v1_from_funding_outpoint(prev_funding_outpoint.0.unwrap()))),
 });
 
 impl Writeable for HTLCForwardInfo {