Dont broadcast HTLC-Timeouts when closing a channel until locktime

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -1905,6 +1905,11 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 						// We can't build an HTLC-Success transaction without the preimage
 						continue;
 					}
+				} else if htlc.0.cltv_expiry > self.best_block.height() + 1 {
+					// Don't broadcast HTLC-Timeout transactions immediately as they dont' meet the
+					// current locktime requirements on-chain. We will broadcast them when the
+					// commitment transaction confirms automatically.
+					continue;
 				} else { None };
 				if let Some(htlc_tx) = self.onchain_tx_handler.get_fully_signed_htlc_tx(
 					&::bitcoin::OutPoint { txid, vout }, &preimage) {