Add HTLC support to BOLT 3 commitment transaction

[NishantBansal2003]

ref: #111

Bolts ref:

• https://github.com/lightning/bolts/blob/master/03-transactions.md
• https://github.com/lightning/bolts/blob/master/05-onchain.md

Verification

Anchor test vectors (local signatures): https://github.com/ACINQ/eclair/blob/master/eclair-core/src/test/resources/bolt3-tx-test-vectors-anchor-outputs-zero-fee-htlc-tx-format.txt

Custom tests on top of commit ACINQ/eclair@26d035070 (after this commit, eclair removed support for non-anchor channels), with the diff below:

Eclair diff

diff --git a/eclair-core/src/test/scala/fr/acinq/eclair/transactions/TestVectorsSpec.scala b/eclair-core/src/test/scala/fr/acinq/eclair/transactions/TestVectorsSpec.scala
index 1931aa8b1..1623fb59e 100644
--- a/eclair-core/src/test/scala/fr/acinq/eclair/transactions/TestVectorsSpec.scala
+++ b/eclair-core/src/test/scala/fr/acinq/eclair/transactions/TestVectorsSpec.scala
@@ -456,6 +456,199 @@ class StaticRemoteKeyTestVectorSpec extends TestVectorsSpec {
   override def filename: String = "/bolt3-tx-test-vectors-static-remotekey-format.txt"
   override def channelFeatures: Set[ChannelTypeFeature] = Set(Features.StaticRemoteKey)
   // @formatter:on
+
+  test("commitment_tx_with_htlc_amount_msat_not_multiple_of_1000_legacy") {
+    val name = "commitment_tx_with_htlc_amount_msat_not_multiple_of_1000_legacy"
+    val htlc = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000999 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set(htlc), FeeratePerKw(647 sat), toLocal = (7000000000L - 2000999L) msat, toRemote = 3000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_htlc_value_equals_non_htlc_value_legacy") {
+    val name = "commitment_tx_with_htlc_value_equals_non_htlc_value_legacy"
+    val htlc = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000000000 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set(htlc), FeeratePerKw(15_000 sat), toLocal = (8000000000L - 2000000000L) msat, toRemote = 2000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_non_htlc_outputs_between_htlc_outputs_legacy") {
+    val name = "commitment_tx_with_non_htlc_outputs_between_htlc_outputs_legacy"
+    val htlc1 = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000000000L msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val htlc2 = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 1, 4000000000L msat, ByteVector32.Zeroes, CltvExpiry(501), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set[DirectedHtlc](htlc1, htlc2), FeeratePerKw(15000 sat), toLocal = (7000000000L - 2000000000L - 4000000000L) msat, toRemote = 3000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_asymmetric_dust_limits_legacy") {
+    val name = "commitment_tx_with_asymmetric_dust_limits_legacy"
+    val htlc = IncomingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 20000000 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set[DirectedHtlc](htlc), FeeratePerKw(15000 sat), toLocal = 7000000000L msat, toRemote = (3000000000L - 20000000L) msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcSuccessTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val redeemScript = Scripts.htlcReceived(localCommitmentKeys.publicKeys, tx.paymentHash, tx.htlcExpiry, commitmentFormat)
+        val localHtlcSig = Transaction.signInput(tx.tx, 0, redeemScript, fr.acinq.bitcoin.SigHash.SIGHASH_ALL, tx.input.txOut.amount, fr.acinq.bitcoin.SigVersion.SIGVERSION_WITNESS_V0, Local.htlc_privkey)
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-success for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${localHtlcSig.dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcTimeoutTx =>
+        fail(s"unexpected htlc-timeout tx for htlc #${tx.htlcId}")
+    }
+  }
 }
 
 class AnchorOutputsTestVectorSpec extends TestVectorsSpec {
@@ -470,4 +663,245 @@ class AnchorOutputsZeroFeeHtlcTxTestVectorSpec extends TestVectorsSpec {
   override def filename: String = "/bolt3-tx-test-vectors-anchor-outputs-zero-fee-htlc-tx-format.txt"
   override def channelFeatures: Set[ChannelTypeFeature] = Set(Features.StaticRemoteKey, Features.AnchorOutputsZeroFeeHtlcTx)
   // @formatter:on
+
+  test("commitment_tx_with_htlc_amount_msat_not_multiple_of_1000_anchor") {
+    val name = "commitment_tx_with_htlc_amount_msat_not_multiple_of_1000_anchor"
+    val htlc = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000999 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set(htlc), FeeratePerKw(647 sat), toLocal = (7000000000L - 2000999L) msat, toRemote = 3000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_htlc_value_equals_non_htlc_value_anchor") {
+    val name = "commitment_tx_with_htlc_value_equals_non_htlc_value_anchor"
+    val htlc = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000000000L msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set(htlc), FeeratePerKw(15000 sat), toLocal = (8000000000L - 2000000000L) msat, toRemote = 2000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_non_htlc_outputs_between_htlc_outputs_anchor") {
+    val name = "commitment_tx_with_non_htlc_outputs_between_htlc_outputs_anchor"
+    val htlc1 = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 2000000000L msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val htlc2 = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 1, 4000000000L msat, ByteVector32.Zeroes, CltvExpiry(501), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set[DirectedHtlc](htlc1, htlc2), FeeratePerKw(15000 sat), toLocal = (7000000000L - 2000000000L - 4000000000L) msat, toRemote = 3000000000L msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_asymmetric_dust_limits_anchor") {
+    val name = "commitment_tx_with_asymmetric_dust_limits_anchor"
+    val htlc = IncomingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 15000000 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set[DirectedHtlc](htlc), FeeratePerKw(15000 sat), toLocal = 7000000000L msat, toRemote = (3000000000L - 15000000L) msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcSuccessTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val redeemScript = Scripts.htlcReceived(localCommitmentKeys.publicKeys, tx.paymentHash, tx.htlcExpiry, commitmentFormat)
+        val localHtlcSig = Transaction.signInput(tx.tx, 0, redeemScript, fr.acinq.bitcoin.SigHash.SIGHASH_ALL, tx.input.txOut.amount, fr.acinq.bitcoin.SigVersion.SIGVERSION_WITNESS_V0, Local.htlc_privkey)
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-success for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${localHtlcSig.dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcTimeoutTx =>
+        fail(s"unexpected htlc-timeout tx for htlc #${tx.htlcId}")
+    }
+  }
+
+  test("commitment_tx_with_main_output_trimmed_but_htlcs_present_anchor") {
+    val name = "commitment_tx_with_main_output_trimmed_but_htlcs_present_anchor"
+    val htlc = OutgoingHtlc(UpdateAddHtlc(ByteVector32.Zeroes, 0, 5000000 msat, ByteVector32.Zeroes, CltvExpiry(500), TestConstants.emptyOnionPacket, None, Reputation.maxEndorsement, None))
+    val spec = CommitmentSpec(Set(htlc), FeeratePerKw(15000 sat), toLocal = (10000000000L - 5000000L) msat, toRemote = 0 msat)
+    val dustLimit = 546.sat
+
+    println()
+    println(s"name: $name")
+
+    val outputs = Transactions.makeCommitTxOutputs(
+      Local.funding_pubkey,
+      Remote.funding_pubkey,
+      localCommitmentKeys.publicKeys,
+      payCommitTxFees = true,
+      dustLimit,
+      Local.toSelfDelay,
+      spec,
+      commitmentFormat
+    )
+    val unsignedCommitTx = Transactions.makeCommitTx(
+      commitTxInput = commitmentInput,
+      commitTxNumber = Local.commitTxNumber,
+      localPaymentBasePoint = Local.payment_basepoint,
+      remotePaymentBasePoint = Remote.payment_basepoint,
+      localIsChannelOpener = true,
+      outputs = outputs)
+    val local_sig = unsignedCommitTx.sign(Local.funding_privkey, Remote.funding_pubkey)
+    val remote_sig = unsignedCommitTx.sign(Remote.funding_privkey, Local.funding_pubkey)
+    println(s"local_signature: ${Scripts.der(local_sig.sig).dropRight(1).toHex}")
+    println(s"remote_signature: ${Scripts.der(remote_sig.sig).dropRight(1).toHex}")
+    val commitTx = unsignedCommitTx.aggregateSigs(Local.funding_pubkey, Remote.funding_pubkey, local_sig, remote_sig)
+    Transaction.correctlySpends(commitTx, Seq(fundingTx), ScriptFlags.STANDARD_SCRIPT_VERIFY_FLAGS)
+
+    val htlcTxs = Transactions.makeHtlcTxs(commitTx, outputs, commitmentFormat).sortBy(_.input.outPoint.index)
+    println(s"num_htlcs: ${htlcTxs.length}")
+    htlcTxs.foreach {
+      case tx: UnsignedHtlcTimeoutTx =>
+        val remoteHtlcSig = tx.localSig(remoteCommitmentKeys)
+        val withRemoteSig = tx.addRemoteSig(localCommitmentKeys, remoteHtlcSig)
+        val localHtlcSig = withRemoteSig.localSig(WalletInputs(Nil, None))
+        println(s"# signature for output #${tx.input.outPoint.index} (htlc-timeout for htlc #${tx.htlcId})")
+        println(s"local_htlc_signature: ${Scripts.der(localHtlcSig).dropRight(1).toHex}")
+        println(s"remote_htlc_signature: ${Scripts.der(remoteHtlcSig).dropRight(1).toHex}")
+      case tx: UnsignedHtlcSuccessTx =>
+        fail(s"unexpected htlc-success tx for htlc #${tx.htlcId}")
+    }
+  }
 }

Note: I split this into smaller commits, so some functions and fields temporarily use #[allow(dead_code)] so that each commit is clippy clean. These annotations are removed in later commits

[erickcestari]

Nice PR! I've added some notes:

[erickcestari]

fulfill_htlc, fail_htlc, update_fee, update_per_commitment_point and advance_commitment_number are missing unit tests.

[erickcestari]

The Htlc cannot be built outside the commitment module.

Suggested change

	id: u64,
	pub id: u64,

[erickcestari]

Shouldn't all of these minimum_feerate tests add the 5 HTLCs to actually verify that the HTLCs are being trimmed correctly?

Suggested change

	let htlcs = bolt3_htlc_list();
	commitment_params.add_htlc(htlcs[1]).unwrap();
	commitment_params.add_htlc(htlcs[2]).unwrap();
	commitment_params.add_htlc(htlcs[3]).unwrap();
	commitment_params.add_htlc(htlcs[4]).unwrap();
	let htlcs = bolt3_htlc_list();
	commitment_params.add_htlc(htlcs[0]).unwrap();
	commitment_params.add_htlc(htlcs[1]).unwrap();
	commitment_params.add_htlc(htlcs[2]).unwrap();
	commitment_params.add_htlc(htlcs[3]).unwrap();
	commitment_params.add_htlc(htlcs[4]).unwrap();

[erickcestari]

Shouldn't we use the same htlc_basepoint that we sent to the target in the open_channel message?

[erickcestari]

We could either return an error or assert when an attempt is made to add a duplicate Htlc.

[erickcestari]

nit:

Suggested change

	let (signature, htlc_signature) = config.sign_counterparty_commitment(&state, &holder);
	assert!(htlc_signature.is_empty()); // There are no HTLCs in the initial commitment transaction.
	let (signature, htlc_signatures) = config.sign_counterparty_commitment(&state, &holder);
	assert!(htlc_signatures.is_empty()); // There are no HTLCs in the initial commitment transaction.

[erickcestari]

nit:

Suggested change

	let (local_signature, local_htlc_signsignature) =
	let (local_signature, local_htlc_signatures) =