splice: Improve abort feerate abort msg

Added an explanation for aborting the splice if the feerate is too low

Author: ddustin

eclair-core/src/main/scala/fr/acinq/eclair/channel/ChannelExceptions.scala

@@ -78,6 +78,7 @@ case class InvalidFundingFeerate                   (override val channelId: Byte
 case class InvalidFundingSignature                 (override val channelId: ByteVector32, txId_opt: Option[TxId]) extends ChannelException(channelId, s"invalid funding signature: txId=${txId_opt.map(_.toString()).getOrElse("n/a")}")
 case class InvalidRbfFeerate                       (override val channelId: ByteVector32, proposed: FeeratePerKw, expected: FeeratePerKw) extends ChannelException(channelId, s"invalid rbf attempt: the feerate must be at least $expected, you proposed $proposed")
 case class InvalidSpliceRequest                    (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid splice request")
+case class InvalidSpliceFeerate                    (override val channelId: ByteVector32, proposed: FeeratePerKw, expected: FeeratePerKw) extends ChannelException(channelId, s"invalid splice attempt: the feerate must be at least $expected, you proposed $proposed")
 case class InvalidRbfAlreadyInProgress             (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid rbf attempt: the current rbf attempt must be completed or aborted first")
 case class InvalidSpliceAlreadyInProgress          (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid splice attempt: the current splice attempt must be completed or aborted first")
 case class InvalidRbfTxAbortNotAcked               (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid rbf attempt: our previous tx_abort has not been acked")

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

@@ -979,8 +979,8 @@ class Channel(val nodeParams: NodeParams, val wallet: OnChainChannelFunder with
             log.info("rejecting splice request: channel not quiescent")
             stay() using d.copy(spliceStatus = SpliceStatus.SpliceAborted) sending TxAbort(d.channelId, InvalidSpliceNotQuiescent(d.channelId).getMessage)
           } else if (msg.feerate < nodeParams.currentFeerates.minimum) {
-            log.info("rejecting splice request: feerate too low")
-            stay() using d.copy(spliceStatus = SpliceStatus.SpliceAborted) sending TxAbort(d.channelId, InvalidSpliceRequest(d.channelId).getMessage)
+            log.info(s"rejecting splice request: feerate ${msg.feerate} too low, must be above ${nodeParams.currentFeerates.minimum}")
+            stay() using d.copy(spliceStatus = SpliceStatus.SpliceAborted) sending TxAbort(d.channelId, InvalidSpliceFeerate(d.channelId, msg.feerate, nodeParams.currentFeerates.minimum).getMessage)
           } else if (d.commitments.active.count(_.fundingTxIndex == d.commitments.latest.fundingTxIndex) > 1) {
             val previousTxs = d.commitments.active.filter(_.fundingTxIndex == d.commitments.latest.fundingTxIndex).map(_.fundingTxId)
             log.info("rejecting splice request: the previous splice has unconfirmed rbf attempts ({})", previousTxs.mkString(", "))