splice: Update our_funds during splice_lock

The value of `our_funds` inlightningd is the funds added to the channel during creation. Splicing is a quasi-creation event. This change makes our pending funds be considered funding funds at the moment of splice confirmation.

Changelog-None

Author: ddustin

lightningd/channel_control.c

@@ -1112,6 +1112,11 @@ static void handle_peer_splice_locked(struct channel *channel, const u8 *msg)
 				       " locked_txid %s",
 				       fmt_bitcoin_txid(tmpctx, &locked_txid));
 
+	wallet_htlcsigs_confirm_inflight(channel->peer->ld->wallet, channel,
+					 &inflight->funding->outpoint);
+
+	update_channel_from_inflight(channel->peer->ld, channel, inflight, true);
+
 	/* Stash prev funding data so we can log it after scid is updated
 	 * (to get the blockheight) */
 	prev_our_msats = channel->our_msat;
@@ -1122,11 +1127,6 @@ static void handle_peer_splice_locked(struct channel *channel, const u8 *msg)
 	channel->msat_to_us_min.millisatoshis += splice_amnt * 1000; /* Raw: splicing */
 	channel->msat_to_us_max.millisatoshis += splice_amnt * 1000; /* Raw: splicing */
 
-	wallet_htlcsigs_confirm_inflight(channel->peer->ld->wallet, channel,
-					 &inflight->funding->outpoint);
-
-	update_channel_from_inflight(channel->peer->ld, channel, inflight);
-
 	/* Remember that we got the lockin */
 	wallet_channel_save(channel->peer->ld->wallet, channel);
 

lightningd/dual_open_control.c

@@ -1056,7 +1056,8 @@ static enum watch_result opening_depth_cb(struct lightningd *ld,
 				   &inflight->channel->peer->id);
 
 	if (depth >= inflight->channel->minimum_depth)
-		update_channel_from_inflight(ld, inflight->channel, inflight);
+		update_channel_from_inflight(ld, inflight->channel, inflight,
+					     false);
 
 	dualopend_tell_depth(inflight->channel, txid, depth);
 

lightningd/peer_control.c

@@ -362,7 +362,7 @@ static enum watch_result closed_inflight_depth_cb(struct lightningd *ld,
 		return KEEP_WATCHING;
 
 	/* This is now the main tx. */
-	update_channel_from_inflight(ld, inflight->channel, inflight);
+	update_channel_from_inflight(ld, inflight->channel, inflight, false);
 	channel_fail_saw_onchain(inflight->channel,
 				 REASON_UNKNOWN,
 				 tx,
@@ -2105,13 +2105,19 @@ void peer_disconnect_done(struct lightningd *ld, const u8 *msg)
 
 void update_channel_from_inflight(struct lightningd *ld,
 				  struct channel *channel,
-				  const struct channel_inflight *inflight)
+				  const struct channel_inflight *inflight,
+				  bool is_splice)
 {
 	channel->funding = inflight->funding->outpoint;
 	channel->funding_sats = inflight->funding->total_funds;
 
 	channel->our_funds = inflight->funding->our_funds;
 
+	/* At this point, our_msat *becomes* our_funds because the splice
+	 * confirms. Any excess millisats stay in our_msats */
+	if (is_splice)
+		channel->our_funds = amount_msat_to_sat_round_down(channel->our_msat);
+
 	if (!amount_sat_add_sat_s64(&channel->our_funds, channel->our_funds,
 				    inflight->funding->splice_amnt)) {
 

lightningd/peer_control.h

@@ -128,7 +128,8 @@ void drop_to_chain(struct lightningd *ld, struct channel *channel,
 
 void update_channel_from_inflight(struct lightningd *ld,
 				  struct channel *channel,
-				  const struct channel_inflight *inflight);
+				  const struct channel_inflight *inflight,
+				  bool is_splice);
 
 void channel_watch_funding(struct lightningd *ld, struct channel *channel);