Set correct counterparty_spendable_height for outb local HTLCs

For outbound HTLCs, the counterparty can spend the output
immediately. This fixes the `counterparty_spendable_height` in the
`PackageTemplate` claiming outbound HTLCs on local commitment
transactions, which was previously spuriously set to the HTLC
timeout (at which point *we* can claim the HTLC).

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -3666,19 +3666,19 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 	// Returns (1) `PackageTemplate`s that can be given to the OnchainTxHandler, so that the handler can
 	// broadcast transactions claiming holder HTLC commitment outputs and (2) a holder revokable
 	// script so we can detect whether a holder transaction has been seen on-chain.
-	fn get_broadcasted_holder_claims(&self, holder_tx: &HolderSignedTx, _conf_height: u32) -> (Vec<PackageTemplate>, Option<(ScriptBuf, PublicKey, RevocationKey)>) {
+	fn get_broadcasted_holder_claims(&self, holder_tx: &HolderSignedTx, conf_height: u32) -> (Vec<PackageTemplate>, Option<(ScriptBuf, PublicKey, RevocationKey)>) {
 		let mut claim_requests = Vec::with_capacity(holder_tx.htlc_outputs.len());
 
 		let redeemscript = chan_utils::get_revokeable_redeemscript(&holder_tx.revocation_key, self.on_holder_tx_csv, &holder_tx.delayed_payment_key);
 		let broadcasted_holder_revokable_script = Some((redeemscript.to_p2wsh(), holder_tx.per_commitment_point.clone(), holder_tx.revocation_key.clone()));
 
 		for &(ref htlc, _, _) in holder_tx.htlc_outputs.iter() {
 			if let Some(transaction_output_index) = htlc.transaction_output_index {
-				let htlc_output = if htlc.offered {
+				let (htlc_output, counterparty_spendable_height) = if htlc.offered {
 					let htlc_output = HolderHTLCOutput::build_offered(
 						htlc.amount_msat, htlc.cltv_expiry, self.onchain_tx_handler.channel_type_features().clone()
 					);
-					htlc_output
+					(htlc_output, conf_height)
 				} else {
 					let payment_preimage = if let Some(preimage) = self.payment_preimages.get(&htlc.payment_hash) {
 						preimage.clone()
@@ -3689,12 +3689,12 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 					let htlc_output = HolderHTLCOutput::build_accepted(
 						payment_preimage, htlc.amount_msat, self.onchain_tx_handler.channel_type_features().clone()
 					);
-					htlc_output
+					(htlc_output, htlc.cltv_expiry)
 				};
 				let htlc_package = PackageTemplate::build_package(
 					holder_tx.txid, transaction_output_index,
 					PackageSolvingData::HolderHTLCOutput(htlc_output),
-					htlc.cltv_expiry,
+					counterparty_spendable_height,
 				);
 				claim_requests.push(htlc_package);
 			}