htlcswitch: keep final htlc outcome

channeldb/channel.go

@@ -16,6 +16,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
@@ -135,6 +136,26 @@ var (
 	// sent was a revocation and false when it was a commitment signature.
 	// This is nil in the case of new channels with no updates exchanged.
 	lastWasRevokeKey = []byte("last-was-revoke")
+
+	// finalHtlcsBucket contains the htlcs that have been resolved
+	// definitively. Within this bucket, there is a sub-bucket for each
+	// channel. In each channel bucket, the htlc indices are stored along
+	// with final outcome.
+	//
+	// final-htlcs -> chanID -> htlcIndex -> outcome
+	//
+	// 'outcome' is a byte value that encodes:
+	//
+	//       | true      false
+	// ------+------------------
+	// bit 0 | settled   failed
+	// bit 1 | offchain  onchain
+	//
+	// This bucket is positioned at the root level, because its contents
+	// will be kept independent of the channel lifecycle. This is to avoid
+	// the situation where a channel force-closes autonomously and the user
+	// not being able to query for htlc outcomes anymore.
+	finalHtlcsBucket = []byte("final-htlcs")
 )
 
 var (
@@ -618,6 +639,20 @@ func (c ChannelStatus) String() string {
 	return statusStr
 }
 
+// FinalHtlcByte defines a byte type that encodes information about the final
+// htlc resolution.
+type FinalHtlcByte byte
+
+const (
+	// FinalHtlcSettledBit is the bit that encodes whether the htlc was
+	// settled or failed.
+	FinalHtlcSettledBit FinalHtlcByte = 1 << 0
+
+	// FinalHtlcOffchainBit is the bit that encodes whether the htlc was
+	// resolved offchain or onchain.
+	FinalHtlcOffchainBit FinalHtlcByte = 1 << 1
+)
+
 // OpenChannel encapsulates the persistent and dynamic state of an open channel
 // with a remote node. An open channel supports several options for on-disk
 // serialization depending on the exact context. Full (upon channel creation)
@@ -1043,6 +1078,26 @@ func fetchChanBucketRw(tx kvdb.RwTx, nodeKey *btcec.PublicKey,
 	return chanBucket, nil
 }
 
+func fetchFinalHtlcsBucketRw(tx kvdb.RwTx,
+	chanID lnwire.ShortChannelID) (kvdb.RwBucket, error) {
+
+	finalHtlcsBucket, err := tx.CreateTopLevelBucket(finalHtlcsBucket)
+	if err != nil {
+		return nil, err
+	}
+
+	var chanIDBytes [8]byte
+	byteOrder.PutUint64(chanIDBytes[:], chanID.ToUint64())
+	chanBucket, err := finalHtlcsBucket.CreateBucketIfNotExists(
+		chanIDBytes[:],
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return chanBucket, nil
+}
+
 // fullSync syncs the contents of an OpenChannel while re-using an existing
 // database transaction.
 func (c *OpenChannel) fullSync(tx kvdb.RwTx) error {
@@ -1739,8 +1794,12 @@ func syncNewChannel(tx kvdb.RwTx, c *OpenChannel, addrs []net.Addr) error {
 // persisted to be able to produce a valid commit signature if a restart would
 // occur. This method its to be called when we revoke our prior commitment
 // state.
+//
+// A map is returned of all the htlc resolutions that were locked in in this
+// commitment. Keys correspond to htlc indices and values indicate whether the
+// htlc was settled or failed.
 func (c *OpenChannel) UpdateCommitment(newCommitment *ChannelCommitment,
-	unsignedAckedUpdates []LogUpdate) error {
+	unsignedAckedUpdates []LogUpdate) (map[uint64]bool, error) {
 
 	c.Lock()
 	defer c.Unlock()
@@ -1749,9 +1808,11 @@ func (c *OpenChannel) UpdateCommitment(newCommitment *ChannelCommitment,
 	// state as all, as it's impossible to do so in a protocol compliant
 	// manner.
 	if c.hasChanStatus(ChanStatusRestored) {
-		return ErrNoRestoredChannelMutation
+		return nil, ErrNoRestoredChannelMutation
 	}
 
+	var finalHtlcs = make(map[uint64]bool)
+
 	err := kvdb.Update(c.Db.backend, func(tx kvdb.RwTx) error {
 		chanBucket, err := fetchChanBucketRw(
 			tx, c.IdentityPub, &c.FundingOutpoint, c.ChainHash,
@@ -1822,17 +1883,35 @@ func (c *OpenChannel) UpdateCommitment(newCommitment *ChannelCommitment,
 			return err
 		}
 
-		var validUpdates []LogUpdate
+		// Get the bucket where settled htlcs are recorded.
+		finalHtlcsBucket, err := fetchFinalHtlcsBucketRw(
+			tx, c.ShortChannelID,
+		)
+		if err != nil {
+			return err
+		}
+
+		var unsignedUpdates []LogUpdate
 		for _, upd := range updates {
-			// Filter for updates that are not on our local
-			// commitment.
+			// Gather updates that are not on our local commitment.
 			if upd.LogIndex >= newCommitment.LocalLogIndex {
-				validUpdates = append(validUpdates, upd)
+				unsignedUpdates = append(unsignedUpdates, upd)
+
+				continue
+			}
+
+			// The update was locked in. If the update was a
+			// resolution, then store it in the database.
+			err := processFinalHtlc(
+				finalHtlcsBucket, upd, finalHtlcs,
+			)
+			if err != nil {
+				return err
 			}
 		}
 
 		var b3 bytes.Buffer
-		err = serializeLogUpdates(&b3, validUpdates)
+		err = serializeLogUpdates(&b3, unsignedUpdates)
 		if err != nil {
 			return fmt.Errorf("unable to serialize log updates: %v", err)
 		}
@@ -1843,12 +1922,57 @@ func (c *OpenChannel) UpdateCommitment(newCommitment *ChannelCommitment,
 		}
 
 		return nil
-	}, func() {})
+	}, func() {
+		finalHtlcs = make(map[uint64]bool)
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	c.LocalCommitment = *newCommitment
+
+	return finalHtlcs, nil
+}
+
+// processFinalHtlc stores a final htlc outcome in the database if signaled via
+// the supplied log update. An in-memory htlcs map is updated too.
+func processFinalHtlc(finalHtlcsBucket walletdb.ReadWriteBucket, upd LogUpdate,
+	finalHtlcs map[uint64]bool) error {
+
+	var (
+		settled bool
+		id      uint64
+	)
+
+	switch msg := upd.UpdateMsg.(type) {
+	case *lnwire.UpdateFulfillHTLC:
+		settled = true
+		id = msg.ID
+
+	case *lnwire.UpdateFailHTLC:
+		settled = false
+		id = msg.ID
+
+	case *lnwire.UpdateFailMalformedHTLC:
+		settled = false
+		id = msg.ID
+
+	default:
+		return nil
+	}
+
+	err := putFinalHtlc(
+		finalHtlcsBucket, id,
+		FinalHtlcInfo{
+			Settled:  settled,
+			Offchain: true,
+		},
+	)
 	if err != nil {
 		return err
 	}
 
-	c.LocalCommitment = *newCommitment
+	finalHtlcs[id] = settled
 
 	return nil
 }
@@ -2681,6 +2805,36 @@ func (c *OpenChannel) AdvanceCommitChainTail(fwdPkg *FwdPkg,
 	return nil
 }
 
+// FinalHtlcInfo contains information about the final outcome of an htlc.
+type FinalHtlcInfo struct {
+	// Settled is true is the htlc was settled. If false, the htlc was
+	// failed.
+	Settled bool
+
+	// Offchain indicates whether the htlc was resolved off-chain or
+	// on-chain.
+	Offchain bool
+}
+
+// putFinalHtlc writes the final htlc outcome to the database. Additionally it
+// records whether the htlc was resolved off-chain or on-chain.
+func putFinalHtlc(finalHtlcsBucket kvdb.RwBucket, id uint64,
+	info FinalHtlcInfo) error {
+
+	var key [8]byte
+	byteOrder.PutUint64(key[:], id)
+
+	var finalHtlcByte FinalHtlcByte
+	if info.Settled {
+		finalHtlcByte |= FinalHtlcSettledBit
+	}
+	if info.Offchain {
+		finalHtlcByte |= FinalHtlcOffchainBit
+	}
+
+	return finalHtlcsBucket.Put(key[:], []byte{byte(finalHtlcByte)})
+}
+
 // NextLocalHtlcIndex returns the next unallocated local htlc index. To ensure
 // this always returns the next index that has been not been allocated, this
 // will first try to examine any pending commitments, before falling back to the

channeldb/channel_test.go

@@ -641,7 +641,7 @@ func TestChannelStateTransition(t *testing.T) {
 		},
 	}
 
-	err = channel.UpdateCommitment(&commitment, unsignedAckedUpdates)
+	_, err = channel.UpdateCommitment(&commitment, unsignedAckedUpdates)
 	require.NoError(t, err, "unable to update commitment")
 
 	// Assert that update is correctly written to the database.
@@ -1457,3 +1457,41 @@ func TestKeyLocatorEncoding(t *testing.T) {
 	// version are equal.
 	require.Equal(t, keyLoc, decodedKeyLoc)
 }
+
+// TestFinalHtlcs tests final htlc storage and retrieval.
+func TestFinalHtlcs(t *testing.T) {
+	t.Parallel()
+
+	fullDB, err := MakeTestDB(t)
+	require.NoError(t, err, "unable to make test database")
+
+	cdb := fullDB.ChannelStateDB()
+
+	chanID := lnwire.ShortChannelID{
+		BlockHeight: 1,
+		TxIndex:     2,
+		TxPosition:  3,
+	}
+
+	// Test offchain final htlcs.
+	const offchainHtlcID = 1
+
+	err = kvdb.Update(cdb.backend, func(tx kvdb.RwTx) error {
+		bucket, err := fetchFinalHtlcsBucketRw(
+			tx, chanID,
+		)
+		require.NoError(t, err)
+
+		return putFinalHtlc(bucket, offchainHtlcID, FinalHtlcInfo{
+			Settled:  true,
+			Offchain: true,
+		})
+	}, func() {})
+	require.NoError(t, err)
+
+	// Test onchain final htlcs.
+	const onchainHtlcID = 2
+
+	err = cdb.PutOnchainFinalHtlcOutcome(chanID, onchainHtlcID, true)
+	require.NoError(t, err)
+}

channeldb/db.go

@@ -1652,6 +1652,27 @@ func (c *ChannelStateDB) FetchHistoricalChannel(outPoint *wire.OutPoint) (
 	return channel, nil
 }
 
+// PutOnchainFinalHtlcOutcome stores the final on-chain outcome of an htlc in
+// the database.
+func (c *ChannelStateDB) PutOnchainFinalHtlcOutcome(
+	chanID lnwire.ShortChannelID, htlcID uint64, settled bool) error {
+
+	return kvdb.Update(c.backend, func(tx kvdb.RwTx) error {
+		finalHtlcsBucket, err := fetchFinalHtlcsBucketRw(tx, chanID)
+		if err != nil {
+			return err
+		}
+
+		return putFinalHtlc(
+			finalHtlcsBucket, htlcID,
+			FinalHtlcInfo{
+				Settled:  settled,
+				Offchain: false,
+			},
+		)
+	}, func() {})
+}
+
 // MakeTestDB creates a new instance of the ChannelDB for testing purposes.
 // A callback which cleans up the created temporary directories is also
 // returned and intended to be executed after the test completes.

channeldb/db_test.go

@@ -355,7 +355,7 @@ func TestRestoreChannelShells(t *testing.T) {
 	// Ensure that it isn't possible to modify the commitment state machine
 	// of this restored channel.
 	channel := nodeChans[0]
-	err = channel.UpdateCommitment(nil, nil)
+	_, err = channel.UpdateCommitment(nil, nil)
 	if err != ErrNoRestoredChannelMutation {
 		t.Fatalf("able to mutate restored channel")
 	}

contractcourt/breacharbiter_test.go

@@ -2451,7 +2451,7 @@ func forceStateTransition(chanA, chanB *lnwallet.LightningChannel) error {
 		return err
 	}
 
-	bobRevocation, _, err := chanB.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := chanB.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}
@@ -2468,7 +2468,7 @@ func forceStateTransition(chanA, chanB *lnwallet.LightningChannel) error {
 		return err
 	}
 
-	aliceRevocation, _, err := chanA.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := chanA.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}

contractcourt/chain_arbitrator.go

@@ -187,6 +187,11 @@ type ChainArbitratorConfig struct {
 	// complete.
 	SubscribeBreachComplete func(op *wire.OutPoint, c chan struct{}) (
 		bool, error)
+
+	// PutFinalHtlcOutcome stores the final outcome of an htlc in the
+	// database.
+	PutFinalHtlcOutcome func(chanId lnwire.ShortChannelID,
+		htlcId uint64, settled bool) error
 }
 
 // ChainArbitrator is a sub-system that oversees the on-chain resolution of all

contractcourt/channel_arbitrator.go

@@ -1460,6 +1460,10 @@ const (
 	// other party time it out, or eventually learn of the pre-image, in
 	// which case we'll claim on chain.
 	HtlcIncomingWatchAction = 5
+
+	// HtlcIncomingDustFinalAction indicates that we should mark an incoming
+	// dust htlc as final because it can't be claimed on-chain.
+	HtlcIncomingDustFinalAction = 6
 )
 
 // String returns a human readable string describing a chain action.
@@ -1483,6 +1487,9 @@ func (c ChainAction) String() string {
 	case HtlcIncomingWatchAction:
 		return "HtlcIncomingWatchAction"
 
+	case HtlcIncomingDustFinalAction:
+		return "HtlcIncomingDustFinalAction"
+
 	default:
 		return "<unknown action>"
 	}
@@ -1698,6 +1705,10 @@ func (c *ChannelArbitrator) checkCommitChainActions(height uint32,
 				"needed for incoming dust htlc=%x",
 				c.cfg.ChanPoint, htlc.RHash[:])
 
+			actionMap[HtlcIncomingDustFinalAction] = append(
+				actionMap[HtlcIncomingDustFinalAction], htlc,
+			)
+
 			continue
 		}
 
@@ -2213,6 +2224,27 @@ func (c *ChannelArbitrator) prepContractResolutions(
 				htlcResolvers = append(htlcResolvers, resolver)
 			}
 
+		// We've lost an htlc because it isn't manifested on the
+		// commitment transaction that closed the channel.
+		case HtlcIncomingDustFinalAction:
+			for _, htlc := range htlcs {
+				htlc := htlc
+
+				key := channeldb.CircuitKey{
+					ChanID: c.cfg.ShortChanID,
+					HtlcID: htlc.HtlcIndex,
+				}
+
+				// Mark this dust htlc as final failed.
+				chainArbCfg := c.cfg.ChainArbitratorConfig
+				err := chainArbCfg.PutFinalHtlcOutcome(
+					key.ChanID, key.HtlcID, false,
+				)
+				if err != nil {
+					return nil, nil, err
+				}
+			}
+
 		// Finally, if this is an outgoing HTLC we've sent, then we'll
 		// launch a resolver to watch for the pre-image (and settle
 		// backwards), or just timeout.

contractcourt/channel_arbitrator_test.go

@@ -206,6 +206,8 @@ type chanArbTestCtx struct {
 
 	breachSubscribed     chan struct{}
 	breachResolutionChan chan struct{}
+
+	finalHtlcs map[uint64]bool
 }
 
 func (c *chanArbTestCtx) CleanUp() {
@@ -306,6 +308,7 @@ func createTestChannelArbitrator(t *testing.T, log ArbitratorLog,
 
 	chanArbCtx := &chanArbTestCtx{
 		breachSubscribed: make(chan struct{}),
+		finalHtlcs:       make(map[uint64]bool),
 	}
 
 	chanPoint := wire.OutPoint{}
@@ -360,6 +363,13 @@ func createTestChannelArbitrator(t *testing.T, log ArbitratorLog,
 		},
 		Clock:   clock.NewDefaultClock(),
 		Sweeper: mockSweeper,
+		PutFinalHtlcOutcome: func(chanId lnwire.ShortChannelID,
+			htlcId uint64, settled bool) error {
+
+			chanArbCtx.finalHtlcs[htlcId] = settled
+
+			return nil
+		},
 	}
 
 	// We'll use the resolvedChan to synchronize on call to
@@ -966,6 +976,12 @@ func TestChannelArbitratorLocalForceClosePendingHtlc(t *testing.T) {
 		t.Fatalf("unable to stop chan arb: %v", err)
 	}
 
+	// Assert that a final resolution was stored for the incoming dust htlc.
+	expectedFinalHtlcs := map[uint64]bool{
+		incomingDustHtlc.HtlcIndex: false,
+	}
+	require.Equal(t, expectedFinalHtlcs, chanArbCtx.finalHtlcs)
+
 	// We'll no re-create the resolver, notice that we use the existing
 	// arbLog so it carries over the same on-disk state.
 	chanArbCtxNew, err := chanArbCtx.Restart(nil)

contractcourt/htlc_incoming_contest_resolver.go

@@ -50,6 +50,18 @@ func newIncomingContestResolver(
 	}
 }
 
+func (h *htlcIncomingContestResolver) processFinalHtlcFail() error {
+	// Mark the htlc as final failed.
+	err := h.ChainArbitratorConfig.PutFinalHtlcOutcome(
+		h.ChannelArbitratorConfig.ShortChanID, h.htlc.HtlcIndex, false,
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // Resolve attempts to resolve this contract. As we don't yet know of the
 // preimage for the contract, we'll wait for one of two things to happen:
 //
@@ -83,6 +95,10 @@ func (h *htlcIncomingContestResolver) Resolve() (ContractResolver, error) {
 		// link has ran.
 		h.resolved = true
 
+		if err := h.processFinalHtlcFail(); err != nil {
+			return nil, err
+		}
+
 		// We write a report to disk that indicates we could not decode
 		// the htlc.
 		resReport := h.report().resolverReport(
@@ -129,6 +145,10 @@ func (h *htlcIncomingContestResolver) Resolve() (ContractResolver, error) {
 			h.htlcExpiry, currentHeight)
 		h.resolved = true
 
+		if err := h.processFinalHtlcFail(); err != nil {
+			return nil, err
+		}
+
 		// Finally, get our report and checkpoint our resolver with a
 		// timeout outcome report.
 		report := h.report().resolverReport(
@@ -201,6 +221,10 @@ func (h *htlcIncomingContestResolver) Resolve() (ContractResolver, error) {
 
 			h.resolved = true
 
+			if err := h.processFinalHtlcFail(); err != nil {
+				return nil, err
+			}
+
 			// Checkpoint our resolver with an abandoned outcome
 			// because we take no further action on this htlc.
 			report := h.report().resolverReport(
@@ -343,6 +367,10 @@ func (h *htlcIncomingContestResolver) Resolve() (ContractResolver, error) {
 					h.htlcExpiry, currentHeight)
 				h.resolved = true
 
+				if err := h.processFinalHtlcFail(); err != nil {
+					return nil, err
+				}
+
 				report := h.report().resolverReport(
 					nil,
 					channeldb.ResolverTypeIncomingHtlc,

contractcourt/htlc_incoming_resolver_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/stretchr/testify/require"
 )
 
 const (
@@ -298,14 +299,15 @@ func (o *mockOnionProcessor) ReconstructHopIterator(r io.Reader, rHash []byte) (
 }
 
 type incomingResolverTestContext struct {
-	registry       *mockRegistry
-	witnessBeacon  *mockWitnessBeacon
-	resolver       *htlcIncomingContestResolver
-	notifier       *mock.ChainNotifier
-	onionProcessor *mockOnionProcessor
-	resolveErr     chan error
-	nextResolver   ContractResolver
-	t              *testing.T
+	registry               *mockRegistry
+	witnessBeacon          *mockWitnessBeacon
+	resolver               *htlcIncomingContestResolver
+	notifier               *mock.ChainNotifier
+	onionProcessor         *mockOnionProcessor
+	resolveErr             chan error
+	nextResolver           ContractResolver
+	finalHtlcOutcomeStored bool
+	t                      *testing.T
 }
 
 func newIncomingResolverTestContext(t *testing.T, isExit bool) *incomingResolverTestContext {
@@ -323,12 +325,27 @@ func newIncomingResolverTestContext(t *testing.T, isExit bool) *incomingResolver
 
 	checkPointChan := make(chan struct{}, 1)
 
+	c := &incomingResolverTestContext{
+		registry:       registry,
+		witnessBeacon:  witnessBeacon,
+		notifier:       notifier,
+		onionProcessor: onionProcessor,
+		t:              t,
+	}
+
 	chainCfg := ChannelArbitratorConfig{
 		ChainArbitratorConfig: ChainArbitratorConfig{
 			Notifier:       notifier,
 			PreimageDB:     witnessBeacon,
 			Registry:       registry,
 			OnionProcessor: onionProcessor,
+			PutFinalHtlcOutcome: func(chanId lnwire.ShortChannelID,
+				htlcId uint64, settled bool) error {
+
+				c.finalHtlcOutcomeStored = true
+
+				return nil
+			},
 		},
 		PutResolverReport: func(_ kvdb.RwTx,
 			_ *channeldb.ResolverReport) error {
@@ -346,7 +363,8 @@ func newIncomingResolverTestContext(t *testing.T, isExit bool) *incomingResolver
 			return nil
 		},
 	}
-	resolver := &htlcIncomingContestResolver{
+
+	c.resolver = &htlcIncomingContestResolver{
 		htlcSuccessResolver: &htlcSuccessResolver{
 			contractResolverKit: *newContractResolverKit(cfg),
 			htlcResolution:      lnwallet.IncomingHtlcResolution{},
@@ -359,14 +377,7 @@ func newIncomingResolverTestContext(t *testing.T, isExit bool) *incomingResolver
 		htlcExpiry: testHtlcExpiry,
 	}
 
-	return &incomingResolverTestContext{
-		registry:       registry,
-		witnessBeacon:  witnessBeacon,
-		resolver:       resolver,
-		notifier:       notifier,
-		onionProcessor: onionProcessor,
-		t:              t,
-	}
+	return c
 }
 
 func (i *incomingResolverTestContext) resolve() {
@@ -400,6 +411,10 @@ func (i *incomingResolverTestContext) waitForResult(expectSuccessRes bool) {
 		if i.nextResolver != nil {
 			i.t.Fatal("expected no next resolver")
 		}
+
+		require.True(i.t, i.finalHtlcOutcomeStored,
+			"expected final htlc outcome to be stored")
+
 		return
 	}
 

contractcourt/htlc_success_resolver.go

@@ -469,6 +469,14 @@ func (h *htlcSuccessResolver) resolveRemoteCommitOutput() (
 func (h *htlcSuccessResolver) checkpointClaim(spendTx *chainhash.Hash,
 	outcome channeldb.ResolverOutcome) error {
 
+	// Mark the htlc as final settled.
+	err := h.ChainArbitratorConfig.PutFinalHtlcOutcome(
+		h.ChannelArbitratorConfig.ShortChanID, h.htlc.HtlcIndex, true,
+	)
+	if err != nil {
+		return err
+	}
+
 	// Create a resolver report for claiming of the htlc itself.
 	amt := btcutil.Amount(h.htlcResolution.SweepSignDesc.Output.Value)
 	reports := []*channeldb.ResolverReport{

contractcourt/htlc_success_resolver_test.go

@@ -31,6 +31,8 @@ type htlcResolverTestContext struct {
 	resolverResultChan chan resolveResult
 	resolutionChan     chan ResolutionMsg
 
+	finalHtlcOutcomeStored bool
+
 	t *testing.T
 }
 
@@ -75,6 +77,13 @@ func newHtlcResolverTestContext(t *testing.T,
 				testCtx.resolutionChan <- msgs[0]
 				return nil
 			},
+			PutFinalHtlcOutcome: func(chanId lnwire.ShortChannelID,
+				htlcId uint64, settled bool) error {
+
+				testCtx.finalHtlcOutcomeStored = true
+
+				return nil
+			},
 		},
 		PutResolverReport: func(_ kvdb.RwTx,
 			report *channeldb.ResolverReport) error {
@@ -186,6 +195,7 @@ func TestHtlcSuccessSingleStage(t *testing.T) {
 			reports: []*channeldb.ResolverReport{
 				claim,
 			},
+			finalHtlcStored: true,
 		},
 	}
 
@@ -269,6 +279,7 @@ func TestHtlcSuccessSecondStageResolution(t *testing.T) {
 				secondStage,
 				firstStage,
 			},
+			finalHtlcStored: true,
 		},
 	}
 
@@ -450,6 +461,7 @@ func TestHtlcSuccessSecondStageResolutionSweeper(t *testing.T) {
 				secondStage,
 				firstStage,
 			},
+			finalHtlcStored: true,
 		},
 	}
 
@@ -465,9 +477,10 @@ type checkpoint struct {
 	preCheckpoint func(*htlcResolverTestContext, bool) error
 
 	// data we expect the resolver to be checkpointed with next.
-	incubating bool
-	resolved   bool
-	reports    []*channeldb.ResolverReport
+	incubating      bool
+	resolved        bool
+	reports         []*channeldb.ResolverReport
+	finalHtlcStored bool
 }
 
 // testHtlcSuccess tests resolution of a success resolver. It takes a a list of
@@ -573,6 +586,11 @@ func runFromCheckpoint(t *testing.T, ctx *htlcResolverTestContext,
 			}
 		}
 
+		// Check that the final htlc outcome is stored.
+		if cp.finalHtlcStored != ctx.finalHtlcOutcomeStored {
+			t.Fatal("final htlc store expectation failed")
+		}
+
 		// Finally encode the resolver, and store it for later use.
 		b := bytes.Buffer{}
 		if err := resolver.Encode(&b); err != nil {

htlcswitch/link.go

@@ -1920,7 +1920,8 @@ func (l *channelLink) handleUpstreamMsg(msg lnwire.Message) {
 		// As we've just accepted a new state, we'll now
 		// immediately send the remote peer a revocation for our prior
 		// state.
-		nextRevocation, currentHtlcs, err := l.channel.RevokeCurrentCommitment()
+		nextRevocation, currentHtlcs, _, err :=
+			l.channel.RevokeCurrentCommitment()
 		if err != nil {
 			l.log.Errorf("unable to revoke commitment: %v", err)
 			return

htlcswitch/link_isolated_test.go

@@ -179,7 +179,7 @@ func (l *linkTestContext) receiveCommitSigAlice(expHtlcs int) *lnwire.CommitSig
 func (l *linkTestContext) sendRevAndAckBobToAlice() {
 	l.t.Helper()
 
-	rev, _, err := l.bobChannel.RevokeCurrentCommitment()
+	rev, _, _, err := l.bobChannel.RevokeCurrentCommitment()
 	if err != nil {
 		l.t.Fatalf("unable to revoke commitment: %v", err)
 	}

htlcswitch/link_test.go

@@ -1958,7 +1958,7 @@ func handleStateUpdate(link *channelLink,
 		return err
 	}
 
-	remoteRev, _, err := remoteChannel.RevokeCurrentCommitment()
+	remoteRev, _, _, err := remoteChannel.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}
@@ -2062,7 +2062,7 @@ func updateState(batchTick chan time.Time, link *channelLink,
 	}
 
 	// Lastly, send a revocation back to the link.
-	remoteRev, _, err := remoteChannel.RevokeCurrentCommitment()
+	remoteRev, _, _, err := remoteChannel.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}
@@ -3134,7 +3134,7 @@ func TestChannelLinkTrimCircuitsRemoteCommit(t *testing.T) {
 
 	// Next, revoke Bob's current commitment and send it to Alice so that we
 	// can test that Alice's circuits aren't trimmed.
-	rev, _, err := bobChan.RevokeCurrentCommitment()
+	rev, _, _, err := bobChan.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke current commitment")
 
 	_, _, _, _, err = alice.channel.ReceiveRevocation(rev)

lnwallet/channel.go

@@ -4779,15 +4779,17 @@ func (lc *LightningChannel) PendingLocalUpdateCount() uint64 {
 // chain is advanced by a single commitment. This now lowest unrevoked
 // commitment becomes our currently accepted state within the channel. This
 // method also returns the set of HTLC's currently active within the commitment
-// transaction. This return value allows callers to act once an HTLC has been
-// locked into our commitment transaction.
-func (lc *LightningChannel) RevokeCurrentCommitment() (*lnwire.RevokeAndAck, []channeldb.HTLC, error) {
+// transaction and the htlcs the were resolved. This return value allows callers
+// to act once an HTLC has been locked into our commitment transaction.
+func (lc *LightningChannel) RevokeCurrentCommitment() (*lnwire.RevokeAndAck,
+	[]channeldb.HTLC, map[uint64]bool, error) {
+
 	lc.Lock()
 	defer lc.Unlock()
 
 	revocationMsg, err := lc.generateRevocation(lc.currentHeight)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, nil, err
 	}
 
 	lc.log.Tracef("revoking height=%v, now at height=%v",
@@ -4808,11 +4810,11 @@ func (lc *LightningChannel) RevokeCurrentCommitment() (*lnwire.RevokeAndAck, []c
 	// is committed locally.
 	unsignedAckedUpdates := lc.getUnsignedAckedUpdates()
 
-	err = lc.channelState.UpdateCommitment(
+	finalHtlcs, err := lc.channelState.UpdateCommitment(
 		newCommitment, unsignedAckedUpdates,
 	)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, nil, err
 	}
 
 	lc.log.Tracef("state transition accepted: "+
@@ -4825,7 +4827,7 @@ func (lc *LightningChannel) RevokeCurrentCommitment() (*lnwire.RevokeAndAck, []c
 		&lc.channelState.FundingOutpoint,
 	)
 
-	return revocationMsg, newCommitment.Htlcs, nil
+	return revocationMsg, newCommitment.Htlcs, finalHtlcs, nil
 }
 
 // ReceiveRevocation processes a revocation sent by the remote party for the

lnwallet/channel_test.go

@@ -104,7 +104,7 @@ func testAddSettleWorkflow(t *testing.T, tweakless bool) {
 
 	// Bob revokes his prior commitment given to him by Alice, since he now
 	// has a valid signature for a newer commitment.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	// Bob finally send a signature for Alice's commitment transaction.
@@ -135,7 +135,7 @@ func testAddSettleWorkflow(t *testing.T, tweakless bool) {
 	require.NoError(t, err, "alice unable to process bob's new commitment")
 
 	// Alice then generates a revocation for bob.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke alice channel")
 
 	// Finally Bob processes Alice's revocation, at this point the new HTLC
@@ -220,7 +220,7 @@ func testAddSettleWorkflow(t *testing.T, tweakless bool) {
 	err = aliceChannel.ReceiveNewCommitment(bobSig2, bobHtlcSigs2)
 	require.NoError(t, err, "alice unable to process bob's new commitment")
 
-	aliceRevocation2, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation2, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to generate revocation")
 	aliceSig2, aliceHtlcSigs2, _, err := aliceChannel.SignNextCommitment()
 	require.NoError(t, err, "alice unable to sign new commitment")
@@ -239,8 +239,17 @@ func testAddSettleWorkflow(t *testing.T, tweakless bool) {
 	err = bobChannel.ReceiveNewCommitment(aliceSig2, aliceHtlcSigs2)
 	require.NoError(t, err, "bob unable to process alice's new commitment")
 
-	bobRevocation2, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation2, _, finalHtlcs, err := bobChannel.
+		RevokeCurrentCommitment()
+
 	require.NoError(t, err, "bob unable to revoke commitment")
+
+	// Check finalHtlcs for the expected final resolution.
+	require.Len(t, finalHtlcs, 1, "final htlc expected")
+	for _, settled := range finalHtlcs {
+		require.True(t, settled, "final settle expected")
+	}
+
 	fwdPkg, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation2)
 	require.NoError(t, err, "alice unable to process bob's revocation")
 	if len(fwdPkg.Adds) != 0 {
@@ -393,7 +402,7 @@ func TestChannelZeroAddLocalHeight(t *testing.T) {
 
 	// Alice should reply with a revocation.
 	// -----rev----->
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
@@ -570,7 +579,7 @@ func testCommitHTLCSigTieBreak(t *testing.T, restart bool) {
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "unable to receive alice's commitment")
 
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob's commitment")
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err, "unable to receive bob's revocation")
@@ -2312,7 +2321,7 @@ func TestUpdateFeeConcurrentSig(t *testing.T) {
 
 	// Bob can revoke the prior commitment he had. This should lock in the
 	// fee update for him.
-	_, _, err = bobChannel.RevokeCurrentCommitment()
+	_, _, _, err = bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	if chainfee.SatPerKWeight(bobChannel.channelState.LocalCommitment.FeePerKw) != fee {
@@ -2378,7 +2387,7 @@ func TestUpdateFeeSenderCommits(t *testing.T) {
 
 	// Bob can revoke the prior commitment he had. This should lock in the
 	// fee update for him.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	if chainfee.SatPerKWeight(
@@ -2413,7 +2422,7 @@ func TestUpdateFeeSenderCommits(t *testing.T) {
 
 	// Alice can revoke the old commitment, which will lock in the fee
 	// update.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke alice channel")
 
 	if chainfee.SatPerKWeight(
@@ -2480,7 +2489,7 @@ func TestUpdateFeeReceiverCommits(t *testing.T) {
 	// Alice can revoke the prior commitment she had, this will ack
 	// everything received before last commitment signature, but in this
 	// case that is nothing.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	// Bob receives the revocation of the old commitment
@@ -2508,7 +2517,7 @@ func TestUpdateFeeReceiverCommits(t *testing.T) {
 	// Bob can revoke the old commitment. This will ack what he has
 	// received, including the HTLC and fee update. This will lock in the
 	// fee update for bob.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke alice channel")
 
 	if chainfee.SatPerKWeight(
@@ -2542,7 +2551,7 @@ func TestUpdateFeeReceiverCommits(t *testing.T) {
 
 	// After Alice now revokes her old commitment, the fee update should
 	// lock in.
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	if chainfee.SatPerKWeight(
@@ -2644,7 +2653,7 @@ func TestUpdateFeeMultipleUpdates(t *testing.T) {
 
 	// Bob can revoke the prior commitment he had. This should lock in the
 	// fee update for him.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to generate bob revocation")
 
 	if chainfee.SatPerKWeight(
@@ -2680,7 +2689,7 @@ func TestUpdateFeeMultipleUpdates(t *testing.T) {
 
 	// Alice can revoke the old commitment, which will lock in the fee
 	// update.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke alice channel")
 
 	if chainfee.SatPerKWeight(
@@ -3074,7 +3083,7 @@ func TestChanSyncOweCommitment(t *testing.T) {
 	// adding one of her own.
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "bob unable to process alice's commitment")
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSig, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "bob unable to sign commitment")
@@ -3082,7 +3091,7 @@ func TestChanSyncOweCommitment(t *testing.T) {
 	require.NoError(t, err, "alice unable to recv revocation")
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "alice unable to rev bob's commitment")
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -3234,7 +3243,7 @@ func TestChanSyncOweCommitmentPendingRemote(t *testing.T) {
 		// completes, the htlc is settled on the local commitment
 		// transaction. Bob still owes Alice a signature to also settle
 		// the htlc on her local commitment transaction.
-		bobRevoke, _, err := bobChannel.RevokeCurrentCommitment()
+		bobRevoke, _, _, err := bobChannel.RevokeCurrentCommitment()
 		if err != nil {
 			t.Fatalf("unable to revoke commitment: %v", err)
 		}
@@ -3264,7 +3273,7 @@ func TestChanSyncOweCommitmentPendingRemote(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	aliceRevoke, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevoke, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -3330,7 +3339,7 @@ func TestChanSyncOweRevocation(t *testing.T) {
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "bob unable to process alice's commitment")
 
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSig, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "bob unable to sign commitment")
@@ -3342,7 +3351,7 @@ func TestChanSyncOweRevocation(t *testing.T) {
 
 	// At this point, we'll simulate the connection breaking down by Bob's
 	// lack of knowledge of the revocation message that Alice just sent.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 
 	// If we fetch the channel sync messages at this state, then Alice
@@ -3482,7 +3491,7 @@ func TestChanSyncOweRevocationAndCommit(t *testing.T) {
 
 	// Bob generates the revoke and sig message, but the messages don't
 	// reach Alice before the connection dies.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSig, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "bob unable to sign commitment")
@@ -3559,7 +3568,7 @@ func TestChanSyncOweRevocationAndCommit(t *testing.T) {
 	require.NoError(t, err, "alice unable to recv revocation")
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "alice unable to rev bob's commitment")
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -3630,7 +3639,7 @@ func TestChanSyncOweRevocationAndCommitForceTransition(t *testing.T) {
 	// signature for Bob's updated state. Instead she will issue a new
 	// update before sending a new CommitSig. This will lead to Alice's
 	// local commit chain getting height > remote commit chain.
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -3652,7 +3661,7 @@ func TestChanSyncOweRevocationAndCommitForceTransition(t *testing.T) {
 	// Bob then sends his revocation message, but before Alice can process
 	// it (and before he scan send his CommitSig message), then connection
 	// dies.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 
 	// Now if we attempt to synchronize states at this point, Alice should
@@ -3746,7 +3755,7 @@ func TestChanSyncOweRevocationAndCommitForceTransition(t *testing.T) {
 		bobSigMsg.CommitSig, bobSigMsg.HtlcSigs,
 	)
 	require.NoError(t, err, "alice unable to rev bob's commitment")
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -4132,7 +4141,7 @@ func TestChannelRetransmissionFeeUpdate(t *testing.T) {
 
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "bob unable to process alice's commitment")
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSig, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "bob unable to sign commitment")
@@ -4140,7 +4149,7 @@ func TestChannelRetransmissionFeeUpdate(t *testing.T) {
 	require.NoError(t, err, "alice unable to recv revocation")
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "alice unable to rev bob's commitment")
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -4330,7 +4339,7 @@ func TestFeeUpdateOldDiskFormat(t *testing.T) {
 	// transition.
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "bob unable to process alice's commitment")
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSig, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "bob unable to sign commitment")
@@ -4338,7 +4347,7 @@ func TestFeeUpdateOldDiskFormat(t *testing.T) {
 	require.NoError(t, err, "alice unable to recv revocation")
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "alice unable to rev bob's commitment")
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "alice unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to recv revocation")
@@ -5013,7 +5022,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5043,7 +5052,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5087,7 +5096,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5130,11 +5139,18 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	err = aliceChannel.ReceiveFailHTLC(htlc2.ID, []byte("bad"))
 	require.NoError(t, err, "unable to recv htlc cancel")
 
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, finalHtlcs, err := bobChannel.
+		RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
 
+	// Check finalHtlcs for the expected final resolution.
+	require.Len(t, finalHtlcs, 1, "final htlc expected")
+	for _, settled := range finalHtlcs {
+		require.False(t, settled, "final fail expected")
+	}
+
 	// Alice should detect that she doesn't need to forward any Adds's, but
 	// that the Fail has been locked in an can be forwarded.
 	_, adds, settleFails, _, err := aliceChannel.ReceiveRevocation(bobRevocation)
@@ -5179,7 +5195,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5210,7 +5226,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5240,7 +5256,7 @@ func TestLockedInHtlcForwardingSkipAfterRestart(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -5852,13 +5868,13 @@ func TestMaxAsynchronousHtlcs(t *testing.T) {
 	require.NoError(t, err, "unable to receive new commitment")
 
 	// Both sides exchange revocations as in step 4 & 5.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke revocation")
 
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err, "unable to receive revocation")
 
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke revocation")
 
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
@@ -6549,7 +6565,7 @@ func TestChannelRestoreUpdateLogs(t *testing.T) {
 	// Bob receives this commitment signature, and revokes his old state.
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	// When Alice now receives this revocation, she will advance her remote
@@ -6728,7 +6744,7 @@ func TestChannelRestoreUpdateLogsFailedHTLC(t *testing.T) {
 	assertInLogs(t, aliceChannel, 1, 0, 0, 1)
 	restoreAndAssert(t, aliceChannel, 1, 0, 0, 0)
 
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err, "bob unable to process alice's revocation")
@@ -6758,7 +6774,7 @@ func TestChannelRestoreUpdateLogsFailedHTLC(t *testing.T) {
 	// When Alice receives Bob's revocation, the Fail is irrevocably locked
 	// in on both sides. She should compact the logs, removing the HTLC and
 	// the corresponding Fail from the local update log.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err, "unable to receive revocation")
@@ -6974,7 +6990,7 @@ func TestChannelRestoreCommitHeight(t *testing.T) {
 	// Bob receives this commitment signature, and revokes his old state.
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	// Now the HTLC is locked into Bob's commitment, a restoration should
@@ -7004,7 +7020,7 @@ func TestChannelRestoreCommitHeight(t *testing.T) {
 
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	// Now both the local and remote add heights should be properly set.
@@ -7046,7 +7062,7 @@ func TestChannelRestoreCommitHeight(t *testing.T) {
 
 	err = bobChannel.ReceiveNewCommitment(aliceSig, aliceHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	// Since Bob just revoked another commitment, a restoration should
@@ -7082,7 +7098,7 @@ func TestChannelRestoreCommitHeight(t *testing.T) {
 	// Alice should receive the commitment and send over a revocation.
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	// Both heights should be 2 and they are on both commitments.
@@ -7119,7 +7135,7 @@ func TestChannelRestoreCommitHeight(t *testing.T) {
 	// Alice receives commitment, sends revocation.
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	_, _, err = aliceChannel.RevokeCurrentCommitment()
+	_, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke commitment")
 
 	aliceChannel = restoreAndAssertCommitHeights(
@@ -7173,7 +7189,7 @@ func TestForceCloseBorkedState(t *testing.T) {
 	require.NoError(t, err, "unable to sign commit")
 	err = bobChannel.ReceiveNewCommitment(aliceSigs, aliceHtlcSigs)
 	require.NoError(t, err, "unable to receive commitment")
-	revokeMsg, _, err := bobChannel.RevokeCurrentCommitment()
+	revokeMsg, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err, "unable to revoke bob commitment")
 	bobSigs, bobHtlcSigs, _, err := bobChannel.SignNextCommitment()
 	require.NoError(t, err, "unable to sign commit")
@@ -7213,7 +7229,7 @@ func TestForceCloseBorkedState(t *testing.T) {
 	if err != channeldb.ErrChanBorked {
 		t.Fatalf("sign commitment should have failed: %v", err)
 	}
-	_, _, err = aliceChannel.RevokeCurrentCommitment()
+	_, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	if err != channeldb.ErrChanBorked {
 		t.Fatalf("append remove chain tail should have failed")
 	}
@@ -8792,7 +8808,7 @@ func TestChannelUnsignedAckedFailure(t *testing.T) {
 
 	// Alice should reply with a revocation.
 	// -----rev----->
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)
@@ -8817,7 +8833,7 @@ func TestChannelUnsignedAckedFailure(t *testing.T) {
 	// Bob revokes his current commitment and sends a revocation
 	// to Alice.
 	// <----rev------
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = newAliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -8903,7 +8919,7 @@ func TestChannelLocalUnsignedUpdatesFailure(t *testing.T) {
 	// Bob should reply with a revocation and Alice should save the fail as
 	// an unsigned local update.
 	// <----rev-----
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -8987,7 +9003,7 @@ func TestChannelSignedAckRegression(t *testing.T) {
 	require.NoError(t, err)
 
 	// <----rev-----
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9014,7 +9030,7 @@ func TestChannelSignedAckRegression(t *testing.T) {
 	require.NoError(t, err)
 
 	// <----rev-----
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9027,7 +9043,7 @@ func TestChannelSignedAckRegression(t *testing.T) {
 	require.NoError(t, err)
 
 	// -----rev---->
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	fwdPkg, _, _, _, err := newBobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)
@@ -9119,7 +9135,7 @@ func TestIsChannelClean(t *testing.T) {
 	assertCleanOrDirty(false, aliceChannel, bobChannel, t)
 
 	// <---rev---
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9133,7 +9149,7 @@ func TestIsChannelClean(t *testing.T) {
 	assertCleanOrDirty(false, aliceChannel, bobChannel, t)
 
 	// ---rev--->
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)
@@ -9154,7 +9170,7 @@ func TestIsChannelClean(t *testing.T) {
 	assertCleanOrDirty(false, aliceChannel, bobChannel, t)
 
 	// ---rev--->
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)
@@ -9168,7 +9184,7 @@ func TestIsChannelClean(t *testing.T) {
 	assertCleanOrDirty(false, aliceChannel, bobChannel, t)
 
 	// <---rev---
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9192,7 +9208,7 @@ func TestIsChannelClean(t *testing.T) {
 	assertCleanOrDirty(false, aliceChannel, bobChannel, t)
 
 	// <---rev---
-	bobRevocation, _, err = bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err = bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9207,7 +9223,7 @@ func TestIsChannelClean(t *testing.T) {
 
 	// The state should finally be clean after alice sends her revocation.
 	// ---rev--->
-	aliceRevocation, _, err = aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err = aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)
@@ -9346,7 +9362,7 @@ func testGetDustSum(t *testing.T, chantype channeldb.ChannelType) {
 	// Bob now sends a revocation for his prior commitment, and this should
 	// change Alice's perspective to no longer include the first HTLC as
 	// dust.
-	bobRevocation, _, err := bobChannel.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := bobChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = aliceChannel.ReceiveRevocation(bobRevocation)
 	require.NoError(t, err)
@@ -9359,7 +9375,7 @@ func testGetDustSum(t *testing.T, chantype channeldb.ChannelType) {
 	require.NoError(t, err)
 	err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs)
 	require.NoError(t, err)
-	aliceRevocation, _, err := aliceChannel.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := aliceChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 	_, _, _, _, err = bobChannel.ReceiveRevocation(aliceRevocation)
 	require.NoError(t, err)

lnwallet/test_utils.go

@@ -502,7 +502,7 @@ func ForceStateTransition(chanA, chanB *LightningChannel) error {
 		return err
 	}
 
-	bobRevocation, _, err := chanB.RevokeCurrentCommitment()
+	bobRevocation, _, _, err := chanB.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}
@@ -518,7 +518,7 @@ func ForceStateTransition(chanA, chanB *LightningChannel) error {
 		return err
 	}
 
-	aliceRevocation, _, err := chanA.RevokeCurrentCommitment()
+	aliceRevocation, _, _, err := chanA.RevokeCurrentCommitment()
 	if err != nil {
 		return err
 	}

lnwallet/transactions_test.go

@@ -291,7 +291,7 @@ func testVectors(t *testing.T, chanType channeldb.ChannelType, test testCase) {
 	err = remoteChannel.ReceiveNewCommitment(localSig, localHtlcSigs)
 	require.NoError(t, err)
 
-	revMsg, _, err := remoteChannel.RevokeCurrentCommitment()
+	revMsg, _, _, err := remoteChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 
 	_, _, _, _, err = localChannel.ReceiveRevocation(revMsg)
@@ -309,7 +309,7 @@ func testVectors(t *testing.T, chanType channeldb.ChannelType, test testCase) {
 	err = localChannel.ReceiveNewCommitment(remoteSig, remoteHtlcSigs)
 	require.NoError(t, err)
 
-	_, _, err = localChannel.RevokeCurrentCommitment()
+	_, _, _, err = localChannel.RevokeCurrentCommitment()
 	require.NoError(t, err)
 
 	// Now the local node force closes the channel so that we can inspect

server.go

@@ -1165,6 +1165,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		IsForwardedHTLC:               s.htlcSwitch.IsForwardedHTLC,
 		Clock:                         clock.NewDefaultClock(),
 		SubscribeBreachComplete:       s.breachArbiter.SubscribeBreachComplete,
+		PutFinalHtlcOutcome:           s.chanStateDB.PutOnchainFinalHtlcOutcome, // nolint: lll
 	}, dbs.ChanStateDB)
 
 	// Select the configuration and furnding parameters for Bitcoin or