Add maxExcess and addExcessToRecipientPosition params to fundTransact…

…ion calls

These parameters are only supported in a testing branch of bitcoind for now.

eclair-core/src/main/scala/fr/acinq/eclair/blockchain/OnChainWallet.scala

@@ -37,7 +37,7 @@ trait OnChainChannelFunder {
    * Fund the provided transaction by adding inputs (and a change output if necessary).
    * Callers must verify that the resulting transaction isn't sending funds to unexpected addresses (malicious bitcoin node).
    */
-  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long] = Map.empty, feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse]
+  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long] = Map.empty, feeBudget_opt: Option[Satoshi], addExcessToRecipientPosition_opt: Option[Int], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse]
 
   /**
    * Sign a PSBT. Result may be partially signed: only inputs known to our bitcoin wallet will be signed. *
@@ -55,7 +55,7 @@ trait OnChainChannelFunder {
   def publishTransaction(tx: Transaction)(implicit ec: ExecutionContext): Future[TxId]
 
   /** Create a fully signed channel funding transaction with the provided pubkeyScript. */
-  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRate: FeeratePerKw, feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse]
+  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRate: FeeratePerKw, feeBudget_opt: Option[Satoshi], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse]
 
   /**
    * Committing *must* include publishing the transaction on the network.

eclair-core/src/main/scala/fr/acinq/eclair/blockchain/bitcoind/rpc/BitcoinCoreClient.scala

@@ -262,8 +262,8 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient, val onChainKeyManag
     })
   }
 
-  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long] = Map.empty, feeBudget_opt: Option[Satoshi] = None)(implicit ec: ExecutionContext): Future[FundTransactionResponse] = {
-    fundTransaction(tx, FundTransactionOptions(feeRate, replaceable, inputWeights = externalInputsWeight.map { case (outpoint, weight) => InputWeight(outpoint, weight) }.toSeq), feeBudget_opt = feeBudget_opt)
+  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long] = Map.empty, feeBudget_opt: Option[Satoshi] = None, addExcessToRecipientPosition_opt: Option[Int] = None, maxExcess_opt: Option[Satoshi] = None)(implicit ec: ExecutionContext): Future[FundTransactionResponse] = {
+    fundTransaction(tx, FundTransactionOptions(feeRate, replaceable, inputWeights = externalInputsWeight.map { case (outpoint, weight) => InputWeight(outpoint, weight) }.toSeq, add_excess_to_recipient_position = addExcessToRecipientPosition_opt, max_excess = maxExcess_opt), feeBudget_opt = feeBudget_opt)
   }
 
   private def processPsbt(psbt: Psbt, sign: Boolean = true, sighashType: Option[Int] = None)(implicit ec: ExecutionContext): Future[ProcessPsbtResponse] = {
@@ -308,7 +308,7 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient, val onChainKeyManag
     }
   }
 
-  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, targetFeerate: FeeratePerKw, feeBudget_opt: Option[Satoshi] = None)(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
+  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, targetFeerate: FeeratePerKw, feeBudget_opt: Option[Satoshi] = None, maxExcess_opt: Option[Satoshi] = None)(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
 
     def verifyAndSign(tx: Transaction, fees: Satoshi, requestedFeeRate: FeeratePerKw): Future[MakeFundingTxResponse] = {
       import KotlinUtils._
@@ -344,7 +344,7 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient, val onChainKeyManag
       // TODO: we should check that mempoolMinFee is not dangerously high
       feerate <- mempoolMinFee().map(minFee => FeeratePerKw(minFee).max(targetFeerate))
       // we ask bitcoin core to add inputs to the funding tx, and use the specified change address
-      FundTransactionResponse(tx, fee, _) <- fundTransaction(partialFundingTx, FundTransactionOptions(feerate), feeBudget_opt = feeBudget_opt)
+      FundTransactionResponse(tx, fee, _) <- fundTransaction(partialFundingTx, FundTransactionOptions(feerate, add_excess_to_recipient_position = None, max_excess = maxExcess_opt), feeBudget_opt = feeBudget_opt)
       lockedUtxos = tx.txIn.map(_.outPoint)
       signedTx <- unlockIfFails(lockedUtxos)(verifyAndSign(tx, fee, feerate))
     } yield signedTx
@@ -585,7 +585,7 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient, val onChainKeyManag
     val theirOutput = TxOut(amount, pubkeyScript)
     val tx = Transaction(version = 2, txIn = Nil, txOut = theirOutput :: Nil, lockTime = 0)
     for {
-      fundedTx <- fundTransaction(tx, feeratePerKw, replaceable = true)
+      fundedTx <- fundTransaction(tx, feeratePerKw, replaceable = true, addExcessToRecipientPosition_opt = None, maxExcess_opt = None)
       lockedOutputs = fundedTx.tx.txIn.map(_.outPoint)
       theirOutputPos = fundedTx.tx.txOut.indexOf(theirOutput)
       signedPsbt <- unlockIfFails(lockedOutputs)(signPsbt(new Psbt(fundedTx.tx), fundedTx.tx.txIn.indices, fundedTx.tx.txOut.indices.filterNot(_ == theirOutputPos)))
@@ -704,10 +704,10 @@ object BitcoinCoreClient {
     def apply(outPoint: OutPoint, weight: Long): InputWeight = InputWeight(outPoint.txid.value.toHex, outPoint.index, weight)
   }
 
-  case class FundTransactionOptions(feeRate: BigDecimal, replaceable: Boolean, lockUnspents: Boolean, changePosition: Option[Int], input_weights: Option[Seq[InputWeight]])
+  case class FundTransactionOptions(feeRate: BigDecimal, replaceable: Boolean, lockUnspents: Boolean, changePosition: Option[Int], input_weights: Option[Seq[InputWeight]], add_excess_to_recipient_position: Option[Int], max_excess: Option[Satoshi])
 
   object FundTransactionOptions {
-    def apply(feerate: FeeratePerKw, replaceable: Boolean = true, changePosition: Option[Int] = None, inputWeights: Seq[InputWeight] = Nil): FundTransactionOptions = {
+    def apply(feerate: FeeratePerKw, replaceable: Boolean = true, changePosition: Option[Int] = None, inputWeights: Seq[InputWeight] = Nil, add_excess_to_recipient_position: Option[Int] = None, max_excess: Option[Satoshi] = None): FundTransactionOptions = {
       FundTransactionOptions(
         BigDecimal(FeeratePerKB(feerate).toLong).bigDecimal.scaleByPowerOfTen(-8),
         replaceable,
@@ -721,7 +721,9 @@ object BitcoinCoreClient {
         // potentially be double-spent.
         lockUnspents = true,
         changePosition,
-        if (inputWeights.isEmpty) None else Some(inputWeights)
+        if (inputWeights.isEmpty) None else Some(inputWeights),
+        add_excess_to_recipient_position,
+        max_excess
       )
     }
   }

eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/ChannelOpenSingleFunded.scala

@@ -186,7 +186,7 @@ trait ChannelOpenSingleFunded extends SingleFundingHandlers with ErrorHandlers {
           log.info("remote will use fundingMinDepth={}", accept.minimumDepth)
           val localFundingPubkey = keyManager.fundingPublicKey(init.localParams.fundingKeyPath, fundingTxIndex = 0)
           val fundingPubkeyScript = Script.write(Script.pay2wsh(Scripts.multiSig2of2(localFundingPubkey.publicKey, accept.fundingPubkey)))
-          wallet.makeFundingTx(fundingPubkeyScript, init.fundingAmount, init.fundingTxFeerate, init.fundingTxFeeBudget_opt).pipeTo(self)
+          wallet.makeFundingTx(fundingPubkeyScript, init.fundingAmount, init.fundingTxFeerate, init.fundingTxFeeBudget_opt, maxExcess_opt = None).pipeTo(self)
           val params = ChannelParams(init.temporaryChannelId, init.channelConfig, channelFeatures, init.localParams, remoteParams, open.channelFlags)
           goto(WAIT_FOR_FUNDING_INTERNAL) using DATA_WAIT_FOR_FUNDING_INTERNAL(params, init.fundingAmount, init.pushAmount_opt.getOrElse(0 msat), init.commitTxFeerate, accept.fundingPubkey, accept.firstPerCommitmentPoint, d.initFunder.replyTo)
       }

eclair-core/src/main/scala/fr/acinq/eclair/channel/fund/InteractiveTxFunder.scala

@@ -212,7 +212,7 @@ private class InteractiveTxFunder(replyTo: ActorRef[InteractiveTxFunder.Response
       case p: SpliceTxRbf => p.feeBudget_opt
       case _ => None
     }
-    context.pipeToSelf(wallet.fundTransaction(txNotFunded, fundingParams.targetFeerate, replaceable = true, externalInputsWeight = sharedInputWeight, feeBudget_opt = feeBudget_opt)) {
+    context.pipeToSelf(wallet.fundTransaction(txNotFunded, fundingParams.targetFeerate, replaceable = true, externalInputsWeight = sharedInputWeight, feeBudget_opt = feeBudget_opt, addExcessToRecipientPosition_opt = None, maxExcess_opt = None)) {
       case Failure(t) => WalletFailure(t)
       case Success(result) => FundTransactionResult(result.tx, result.changePosition)
     }

eclair-core/src/main/scala/fr/acinq/eclair/channel/publish/ReplaceableTxFunder.scala

@@ -434,7 +434,7 @@ private class ReplaceableTxFunder(nodeParams: NodeParams,
     // start with a dummy output and later merge that dummy output with the optional change output added by bitcoind.
     val txNotFunded = anchorTx.txInfo.tx.copy(txOut = TxOut(dustLimit, Script.pay2wpkh(PlaceHolderPubKey)) :: Nil)
     val anchorWeight = Seq(InputWeight(anchorTx.txInfo.input.outPoint, anchorInputWeight))
-    bitcoinClient.fundTransaction(txNotFunded, FundTransactionOptions(targetFeerate, inputWeights = anchorWeight), feeBudget_opt = None).flatMap { fundTxResponse =>
+    bitcoinClient.fundTransaction(txNotFunded, FundTransactionOptions(targetFeerate, inputWeights = anchorWeight, add_excess_to_recipient_position = None, max_excess = None), feeBudget_opt = None).flatMap { fundTxResponse =>
       // Bitcoin Core may not preserve the order of inputs, we need to make sure the anchor is the first input.
       val txIn = anchorTx.txInfo.tx.txIn ++ fundTxResponse.tx.txIn.filterNot(_.outPoint == anchorTx.txInfo.input.outPoint)
       // We merge our dummy change output with the one added by Bitcoin Core, if any.

eclair-core/src/test/scala/fr/acinq/eclair/blockchain/DummyOnChainWallet.scala

@@ -50,7 +50,7 @@ class DummyOnChainWallet extends OnChainWallet with OnchainPubkeyCache {
 
   override def getP2wpkhPubkey()(implicit ec: ExecutionContext): Future[Crypto.PublicKey] = Future.successful(dummyReceivePubkey)
 
-  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = {
+  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi], addExcessToRecipientPosition_opt: Option[Int], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = {
     funded += (tx.txid -> tx)
     Future.successful(FundTransactionResponse(tx, 0 sat, None))
   }
@@ -62,7 +62,7 @@ class DummyOnChainWallet extends OnChainWallet with OnchainPubkeyCache {
     Future.successful(tx.txid)
   }
 
-  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
+  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
     val tx = DummyOnChainWallet.makeDummyFundingTx(pubkeyScript, amount)
     funded += (tx.fundingTx.txid -> tx.fundingTx)
     Future.successful(tx)
@@ -105,13 +105,13 @@ class NoOpOnChainWallet extends OnChainWallet with OnchainPubkeyCache {
 
   override def getP2wpkhPubkey()(implicit ec: ExecutionContext): Future[Crypto.PublicKey] = Future.successful(dummyReceivePubkey)
 
-  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = Promise().future // will never be completed
+  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi], addExcessToRecipientPosition_opt: Option[Int], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = Promise().future // will never be completed
 
   override def signPsbt(psbt: Psbt, ourInputs: Seq[Int], ourOutputs: Seq[Int])(implicit ec: ExecutionContext): Future[ProcessPsbtResponse] = Promise().future // will never be completed
 
   override def publishTransaction(tx: Transaction)(implicit ec: ExecutionContext): Future[TxId] = Future.successful(tx.txid)
 
-  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = Promise().future // will never be completed
+  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = Promise().future // will never be completed
 
   override def commit(tx: Transaction)(implicit ec: ExecutionContext): Future[Boolean] = Future.successful(true)
 
@@ -152,7 +152,7 @@ class SingleKeyOnChainWallet extends OnChainWallet with OnchainPubkeyCache {
 
   override def getP2wpkhPubkey()(implicit ec: ExecutionContext): Future[Crypto.PublicKey] = Future.successful(pubkey)
 
-  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = synchronized {
+  override def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, externalInputsWeight: Map[OutPoint, Long], feeBudget_opt: Option[Satoshi], addExcessToRecipientPosition_opt: Option[Int], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[FundTransactionResponse] = synchronized {
     val currentAmountIn = tx.txIn.flatMap(txIn => inputs.find(_.txid == txIn.outPoint.txid).flatMap(_.txOut.lift(txIn.outPoint.index.toInt))).map(_.amount).sum
     val amountOut = tx.txOut.map(_.amount).sum
     // We add a single input to reach the desired feerate.
@@ -213,10 +213,10 @@ class SingleKeyOnChainWallet extends OnChainWallet with OnchainPubkeyCache {
     Future.successful(ProcessPsbtResponse(signedPsbt, complete))
   }
 
-  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
+  override def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw, feeBudget_opt: Option[Satoshi], maxExcess_opt: Option[Satoshi])(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
     val tx = Transaction(2, Nil, Seq(TxOut(amount, pubkeyScript)), 0)
     for {
-      fundedTx <- fundTransaction(tx, feeRatePerKw, replaceable = true, feeBudget_opt = feeBudget_opt)
+      fundedTx <- fundTransaction(tx, feeRatePerKw, replaceable = true, feeBudget_opt = feeBudget_opt, addExcessToRecipientPosition_opt = Some(0), maxExcess_opt = maxExcess_opt)
       signedTx <- signTransaction(fundedTx.tx)
     } yield MakeFundingTxResponse(signedTx.tx, 0, fundedTx.fee)
   }