multi: update to fn v2

aliasmgr/aliasmgr.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"sync"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -432,9 +432,9 @@ func (m *Manager) DeleteLocalAlias(alias,
 	}
 
 	// We'll filter the alias set and remove the alias from it.
-	aliasSet = fn.Filter(func(a lnwire.ShortChannelID) bool {
+	aliasSet = fn.Filter(aliasSet, func(a lnwire.ShortChannelID) bool {
 		return a.ToUint64() != alias.ToUint64()
-	}, aliasSet)
+	})
 
 	// If the alias set is empty, we'll delete the base SCID from the
 	// baseToSet map.
@@ -514,11 +514,17 @@ func (m *Manager) RequestAlias() (lnwire.ShortChannelID, error) {
 	// haveAlias returns true if the passed alias is already assigned to a
 	// channel in the baseToSet map.
 	haveAlias := func(maybeNextAlias lnwire.ShortChannelID) bool {
-		return fn.Any(func(aliasList []lnwire.ShortChannelID) bool {
+		return fn.Any(
-			return fn.Any(func(alias lnwire.ShortChannelID) bool {
+			maps.Values(m.baseToSet),
+			func(aliasList []lnwire.ShortChannelID) bool {
+				return fn.Any(
+					aliasList,
+					func(alias lnwire.ShortChannelID) bool {
 						return alias == maybeNextAlias
-			}, aliasList)
+					},
-		}, maps.Values(m.baseToSet))
+				)
+			},
+		)
 	}
 
 	err := kvdb.Update(m.backend, func(tx kvdb.RwTx) error {

chainntnfs/bitcoindnotify/bitcoind.go

@@ -15,7 +15,7 @@ import (
 	"github.com/btcsuite/btcwallet/chain"
 	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/queue"
 )
 

chainntnfs/btcdnotify/btcd.go

@@ -17,7 +17,7 @@ import (
 	"github.com/btcsuite/btcwallet/chain"
 	"github.com/lightningnetwork/lnd/blockcache"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/queue"
 )
 

chainntnfs/interface.go

@@ -13,7 +13,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 var (

chainntnfs/mocks.go

@@ -3,7 +3,7 @@ package chainntnfs
 import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/stretchr/testify/mock"
 )
 

chainreg/chainregistry.go

@@ -23,7 +23,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/chainntnfs/neutrinonotify"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"

chanbackup/backup.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 // LiveChannelSource is an interface that allows us to query for the set of

chanbackup/single.go

@@ -12,7 +12,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnencrypt"
 	"github.com/lightningnetwork/lnd/lnwire"

chanbackup/single_test.go

@@ -13,7 +13,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnencrypt"
 	"github.com/lightningnetwork/lnd/lnwire"

channeldb/channel.go

@@ -19,7 +19,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/walletdb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"

channeldb/channel_test.go

@@ -18,7 +18,7 @@ import (
 	_ "github.com/btcsuite/btcwallet/walletdb/bdb"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/clock"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"

channeldb/migration/lnwire21/custom_records.go

@@ -6,7 +6,7 @@ import (
 	"io"
 	"sort"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
@@ -163,9 +163,12 @@ func (c CustomRecords) SerializeTo(w io.Writer) error {
 // ProduceRecordsSorted converts a slice of record producers into a slice of
 // records and then sorts it by type.
 func ProduceRecordsSorted(recordProducers ...tlv.RecordProducer) []tlv.Record {
-	records := fn.Map(func(producer tlv.RecordProducer) tlv.Record {
+	records := fn.Map(
+		recordProducers,
+		func(producer tlv.RecordProducer) tlv.Record {
 			return producer.Record()
-	}, recordProducers)
+		},
+	)
 
 	// Ensure that the set of records are sorted before we attempt to
 	// decode from the stream, to ensure they're canonical.
@@ -196,9 +199,9 @@ func TlvMapToRecords(tlvMap tlv.TypeMap) []tlv.Record {
 // RecordsAsProducers converts a slice of records into a slice of record
 // producers.
 func RecordsAsProducers(records []tlv.Record) []tlv.RecordProducer {
-	return fn.Map(func(record tlv.Record) tlv.RecordProducer {
+	return fn.Map(records, func(record tlv.Record) tlv.RecordProducer {
 		return &record
-	}, records)
+	})
 }
 
 // EncodeRecords encodes the given records into a byte slice.

channeldb/migration32/mission_control_store.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/btcsuite/btcd/wire"
 	lnwire "github.com/lightningnetwork/lnd/channeldb/migration/lnwire21"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
@@ -371,7 +371,7 @@ func extractMCRoute(r *Route) *mcRoute {
 // extractMCHops extracts the Hop fields that MC actually uses from a slice of
 // Hops.
 func extractMCHops(hops []*Hop) mcHops {
-	return fn.Map(extractMCHop, hops)
+	return fn.Map(hops, extractMCHop)
 }
 
 // extractMCHop extracts the Hop fields that MC actually uses from a Hop.

channeldb/revocation_log.go

@@ -7,7 +7,7 @@ import (
 	"math"
 
 	"github.com/btcsuite/btcd/btcutil"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"

channeldb/revocation_log_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 
 	"github.com/btcsuite/btcd/btcutil"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lntest/channels"
 	"github.com/lightningnetwork/lnd/lnwire"

cmd/commands/cmd_macaroon.go

@@ -10,7 +10,7 @@ import (
 	"strings"
 	"unicode"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/macaroons"
@@ -177,12 +177,15 @@ func bakeMacaroon(ctx *cli.Context) error {
 				"%w", err)
 		}
 
-		ops := fn.Map(func(p *lnrpc.MacaroonPermission) bakery.Op {
+		ops := fn.Map(
+			parsedPermissions,
+			func(p *lnrpc.MacaroonPermission) bakery.Op {
 				return bakery.Op{
 					Entity: p.Entity,
 					Action: p.Action,
 				}
-		}, parsedPermissions)
+			},
+		)
 
 		rawMacaroon, err = macaroons.BakeFromRootKey(macRootKey, ops)
 		if err != nil {

config_builder.go

@@ -33,7 +33,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainreg"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/funding"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/invoices"

contractcourt/anchor_resolver.go

@@ -9,7 +9,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/sweep"
 )

contractcourt/breach_arbitrator.go

@@ -15,7 +15,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"
@@ -1537,9 +1537,9 @@ func (b *BreachArbitrator) createSweepTx(
 	// outputs from the regular, BTC only outputs. So we only need one such
 	// output, which'll carry the custom channel "valuables" from both the
 	// breached commitment and HTLC outputs.
-	hasBlobs := fn.Any(func(i input.Input) bool {
+	hasBlobs := fn.Any(inputs, func(i input.Input) bool {
 		return i.ResolutionBlob().IsSome()
-	}, inputs)
+	})
 	if hasBlobs {
 		weightEstimate.AddP2TROutput()
 	}
@@ -1624,7 +1624,7 @@ func (b *BreachArbitrator) sweepSpendableOutputsTxn(txWeight lntypes.WeightUnit,
 	// First, we'll add the extra sweep output if it exists, subtracting the
 	// amount from the sweep amt.
 	if b.cfg.AuxSweeper.IsSome() {
-		extraChangeOut.WhenResult(func(o sweep.SweepOutput) {
+		extraChangeOut.WhenOk(func(o sweep.SweepOutput) {
 			sweepAmt -= o.Value
 
 			txn.AddTxOut(&o.TxOut)
@@ -1697,7 +1697,7 @@ func (b *BreachArbitrator) sweepSpendableOutputsTxn(txWeight lntypes.WeightUnit,
 	return &justiceTxCtx{
 		justiceTx:  txn,
 		sweepAddr:  pkScript,
-		extraTxOut: extraChangeOut.Option(),
+		extraTxOut: extraChangeOut.OkToSome(),
 		fee:        txFee,
 		inputs:     inputs,
 	}, nil

contractcourt/breach_arbitrator_test.go

@@ -22,7 +22,7 @@ import (
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntest/channels"

contractcourt/briefcase.go

@@ -10,7 +10,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwallet"

contractcourt/briefcase_test.go

@@ -14,7 +14,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnmock"

contractcourt/chain_arbitrator.go

@@ -14,7 +14,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"

contractcourt/chain_watcher.go

@@ -18,7 +18,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnutils"
@@ -451,7 +451,7 @@ func (c *chainWatcher) handleUnknownLocalState(
 		leaseExpiry = c.cfg.chanState.ThawHeight
 	}
 
-	remoteAuxLeaf := fn.ChainOption(
+	remoteAuxLeaf := fn.FlatMapOption(
 		func(l lnwallet.CommitAuxLeaves) input.AuxTapLeaf {
 			return l.RemoteAuxLeaf
 		},
@@ -468,7 +468,7 @@ func (c *chainWatcher) handleUnknownLocalState(
 	// Next, we'll derive our script that includes the revocation base for
 	// the remote party allowing them to claim this output before the CSV
 	// delay if we breach.
-	localAuxLeaf := fn.ChainOption(
+	localAuxLeaf := fn.FlatMapOption(
 		func(l lnwallet.CommitAuxLeaves) input.AuxTapLeaf {
 			return l.LocalAuxLeaf
 		},
@@ -1062,15 +1062,15 @@ func (c *chainWatcher) toSelfAmount(tx *wire.MsgTx) btcutil.Amount {
 			return false
 		}
 
-		return fn.Any(c.cfg.isOurAddr, addrs)
+		return fn.Any(addrs, c.cfg.isOurAddr)
 	}
 
 	// Grab all of the outputs that correspond with our delivery address
 	// or our wallet is aware of.
-	outs := fn.Filter(fn.PredOr(isDeliveryOutput, isWalletOutput), tx.TxOut)
+	outs := fn.Filter(tx.TxOut, fn.PredOr(isDeliveryOutput, isWalletOutput))
 
 	// Grab the values for those outputs.
-	vals := fn.Map(func(o *wire.TxOut) int64 { return o.Value }, outs)
+	vals := fn.Map(outs, func(o *wire.TxOut) int64 { return o.Value })
 
 	// Return the sum.
 	return btcutil.Amount(fn.Sum(vals))

contractcourt/channel_arbitrator.go

@@ -15,7 +15,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/input"
@@ -997,7 +997,7 @@ func (c *ChannelArbitrator) stateStep(
 			getIdx := func(htlc channeldb.HTLC) uint64 {
 				return htlc.HtlcIndex
 			}
-			dustHTLCSet := fn.NewSet(fn.Map(getIdx, dustHTLCs)...)
+			dustHTLCSet := fn.NewSet(fn.Map(dustHTLCs, getIdx)...)
 			err = c.abandonForwards(dustHTLCSet)
 			if err != nil {
 				return StateError, closeTx, err
@@ -1306,7 +1306,7 @@ func (c *ChannelArbitrator) stateStep(
 				return htlc.HtlcIndex
 			}
 			remoteDangling := fn.NewSet(fn.Map(
-				getIdx, htlcActions[HtlcFailDanglingAction],
+				htlcActions[HtlcFailDanglingAction], getIdx,
 			)...)
 			err := c.abandonForwards(remoteDangling)
 			if err != nil {

contractcourt/channel_arbitrator_test.go

@@ -16,7 +16,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"

contractcourt/commit_sweep_resolver.go

@@ -13,7 +13,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/sweep"

contractcourt/contract_resolver.go

@@ -9,7 +9,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btclog/v2"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 var (

contractcourt/htlc_incoming_contest_resolver.go

@@ -10,7 +10,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/invoices"

contractcourt/htlc_lease_resolver.go

@@ -6,7 +6,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/tlv"
 )

contractcourt/htlc_outgoing_contest_resolver.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 

contractcourt/htlc_success_resolver.go

@@ -12,7 +12,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/labels"

contractcourt/htlc_success_resolver_test.go

@@ -12,7 +12,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/kvdb"

contractcourt/htlc_timeout_resolver.go

@@ -12,7 +12,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnutils"

contractcourt/htlc_timeout_resolver_test.go

@@ -14,7 +14,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/input"

contractcourt/utxonursery.go

@@ -15,7 +15,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/labels"

contractcourt/utxonursery_test.go

@@ -18,7 +18,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntest/mock"
 	"github.com/lightningnetwork/lnd/lnwallet"

discovery/gossiper.go

@@ -19,7 +19,7 @@ import (
 	"github.com/lightningnetwork/lnd/batch"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"

discovery/gossiper_test.go

@@ -24,7 +24,7 @@ import (
 	"github.com/lightningnetwork/lnd/batch"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"

funding/aux_funding.go

@@ -2,7 +2,7 @@ package funding
 
 import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/msgmux"

funding/manager.go

@@ -23,7 +23,7 @@ import (
 	"github.com/lightningnetwork/lnd/chanacceptor"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/discovery"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"

funding/manager_test.go

@@ -27,7 +27,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channelnotifier"
 	"github.com/lightningnetwork/lnd/discovery"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"

go.mod

@@ -36,13 +36,13 @@ require (
 	github.com/lightningnetwork/lightning-onion v1.2.1-0.20240712235311-98bd56499dfb
 	github.com/lightningnetwork/lnd/cert v1.2.2
 	github.com/lightningnetwork/lnd/clock v1.1.1
-	github.com/lightningnetwork/lnd/fn v1.2.5
+	github.com/lightningnetwork/lnd/fn/v2 v2.0.2
 	github.com/lightningnetwork/lnd/healthcheck v1.2.6
 	github.com/lightningnetwork/lnd/kvdb v1.4.11
 	github.com/lightningnetwork/lnd/queue v1.1.1
 	github.com/lightningnetwork/lnd/sqldb v1.0.5
 	github.com/lightningnetwork/lnd/ticker v1.1.1
-	github.com/lightningnetwork/lnd/tlv v1.2.6
+	github.com/lightningnetwork/lnd/tlv v1.3.0
 	github.com/lightningnetwork/lnd/tor v1.1.4
 	github.com/ltcsuite/ltcd v0.0.0-20190101042124-f37f8bf35796
 	github.com/miekg/dns v1.1.43

go.sum

@@ -456,8 +456,8 @@ github.com/lightningnetwork/lnd/cert v1.2.2 h1:71YK6hogeJtxSxw2teq3eGeuy4rHGKcFf
 github.com/lightningnetwork/lnd/cert v1.2.2/go.mod h1:jQmFn/Ez4zhDgq2hnYSw8r35bqGVxViXhX6Cd7HXM6U=
 github.com/lightningnetwork/lnd/clock v1.1.1 h1:OfR3/zcJd2RhH0RU+zX/77c0ZiOnIMsDIBjgjWdZgA0=
 github.com/lightningnetwork/lnd/clock v1.1.1/go.mod h1:mGnAhPyjYZQJmebS7aevElXKTFDuO+uNFFfMXK1W8xQ=
-github.com/lightningnetwork/lnd/fn v1.2.5 h1:pGMz0BDUxrhvOtShD4FIysdVy+ulfFAnFvTKjZO5Pp8=
+github.com/lightningnetwork/lnd/fn/v2 v2.0.2 h1:M7o2lYrh/zCp+lntPB3WP/rWTu5U+4ssyHW+kqNJ0fs=
-github.com/lightningnetwork/lnd/fn v1.2.5/go.mod h1:SyFohpVrARPKH3XVAJZlXdVe+IwMYc4OMAvrDY32kw0=
+github.com/lightningnetwork/lnd/fn/v2 v2.0.2/go.mod h1:TOzwrhjB/Azw1V7aa8t21ufcQmdsQOQMDtxVOQWNl8s=
 github.com/lightningnetwork/lnd/healthcheck v1.2.6 h1:1sWhqr93GdkWy4+6U7JxBfcyZIE78MhIHTJZfPx7qqI=
 github.com/lightningnetwork/lnd/healthcheck v1.2.6/go.mod h1:Mu02um4CWY/zdTOvFje7WJgJcHyX2zq/FG3MhOAiGaQ=
 github.com/lightningnetwork/lnd/kvdb v1.4.11 h1:fk1HMVFrsVK3xqU7q+JWHRgBltw/a2qIg1E3zazMb/8=
@@ -468,8 +468,8 @@ github.com/lightningnetwork/lnd/sqldb v1.0.5 h1:ax5vBPf44tN/uD6C5+hBPBjOJ7cRMrUL
 github.com/lightningnetwork/lnd/sqldb v1.0.5/go.mod h1:OG09zL/PHPaBJefp4HsPz2YLUJ+zIQHbpgCtLnOx8I4=
 github.com/lightningnetwork/lnd/ticker v1.1.1 h1:J/b6N2hibFtC7JLV77ULQp++QLtCwT6ijJlbdiZFbSM=
 github.com/lightningnetwork/lnd/ticker v1.1.1/go.mod h1:waPTRAAcwtu7Ji3+3k+u/xH5GHovTsCoSVpho0KDvdA=
-github.com/lightningnetwork/lnd/tlv v1.2.6 h1:icvQG2yDr6k3ZuZzfRdG3EJp6pHurcuh3R6dg0gv/Mw=
+github.com/lightningnetwork/lnd/tlv v1.3.0 h1:exS/KCPEgpOgviIttfiXAPaUqw2rHQrnUOpP7HPBPiY=
-github.com/lightningnetwork/lnd/tlv v1.2.6/go.mod h1:/CmY4VbItpOldksocmGT4lxiJqRP9oLxwSZOda2kzNQ=
+github.com/lightningnetwork/lnd/tlv v1.3.0/go.mod h1:pJuiBj1ecr1WWLOtcZ+2+hu9Ey25aJWFIsjmAoPPnmc=
 github.com/lightningnetwork/lnd/tor v1.1.4 h1:TUW27EXqoZCcCAQPlD4aaDfh8jMbBS9CghNz50qqwtA=
 github.com/lightningnetwork/lnd/tor v1.1.4/go.mod h1:qSRB8llhAK+a6kaTPWOLLXSZc6Hg8ZC0mq1sUQ/8JfI=
 github.com/ltcsuite/ltcd v0.0.0-20190101042124-f37f8bf35796 h1:sjOGyegMIhvgfq5oaue6Td+hxZuf3tDC8lAPrFldqFw=

graph/builder.go

@@ -16,7 +16,7 @@ import (
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/batch"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"

graph/db/models/channel_edge_info.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 // ChannelEdgeInfo represents a fully authenticated channel along with all its

htlcswitch/interceptable_switch.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/go-errors/errors"
 	"github.com/lightningnetwork/lnd/chainntnfs"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/lntypes"

htlcswitch/interfaces.go

@@ -6,7 +6,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/invoices"
 	"github.com/lightningnetwork/lnd/lntypes"

htlcswitch/link.go

@@ -16,7 +16,7 @@ import (
 	"github.com/btcsuite/btclog/v2"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hodl"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"

htlcswitch/link_test.go

@@ -26,7 +26,7 @@ import (
 	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hodl"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"

htlcswitch/mock.go

@@ -24,7 +24,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/invoices"

htlcswitch/quiescer.go

@@ -6,7 +6,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btclog/v2"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 )

htlcswitch/quiescer_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/stretchr/testify/require"

htlcswitch/switch.go

@@ -17,7 +17,7 @@ import (
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"
 	"github.com/lightningnetwork/lnd/kvdb"

htlcswitch/switch_test.go

@@ -17,7 +17,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch/hodl"
 	"github.com/lightningnetwork/lnd/htlcswitch/hop"

input/input.go

@@ -6,7 +6,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/tlv"
 )

input/mocks.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2/schnorr/musig2"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/tlv"

input/script_utils.go

@@ -14,7 +14,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnutils"
 	"golang.org/x/crypto/ripemd160"

input/taproot.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/waddrmgr"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 const (

input/taproot_test.go

@@ -10,7 +10,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/stretchr/testify/require"

intercepted_forward.go

@@ -3,7 +3,7 @@ package lnd
 import (
 	"errors"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"

invoices/modification_interceptor.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"sync/atomic"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 var (

itest/lnd_funding_test.go

@@ -12,7 +12,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/chainreg"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/funding"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/labels"

itest/lnd_sweep_test.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
@@ -1119,9 +1119,9 @@ func testSweepHTLCs(ht *lntest.HarnessTest) {
 		// The sweeping tx has two inputs, one from wallet, the other
 		// from the force close tx. We now check whether the first tx
 		// spends from the force close tx of Alice->Bob.
-		found := fn.Any(func(inp *wire.TxIn) bool {
+		found := fn.Any(txns[0].TxIn, func(inp *wire.TxIn) bool {
 			return inp.PreviousOutPoint.Hash == abCloseTxid
-		}, txns[0].TxIn)
+		})
 
 		// If the first tx spends an outpoint from the force close tx
 		// of Alice->Bob, then it must be the incoming HTLC sweeping

lnrpc/devrpc/dev_server.go

@@ -16,7 +16,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/lnrpc"

lnrpc/marshall_utils.go

@@ -11,7 +11,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/lightningnetwork/lnd/aliasmgr"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"golang.org/x/exp/maps"
@@ -221,12 +221,18 @@ func UnmarshallCoinSelectionStrategy(strategy CoinSelectionStrategy,
 // MarshalAliasMap converts a ScidAliasMap to its proto counterpart. This is
 // used in various RPCs that handle scid alias mappings.
 func MarshalAliasMap(scidMap aliasmgr.ScidAliasMap) []*AliasMap {
-	return fn.Map(func(base lnwire.ShortChannelID) *AliasMap {
+	return fn.Map(
+		maps.Keys(scidMap),
+		func(base lnwire.ShortChannelID) *AliasMap {
 			return &AliasMap{
 				BaseScid: base.ToUint64(),
-			Aliases: fn.Map(func(a lnwire.ShortChannelID) uint64 {
+				Aliases: fn.Map(
+					scidMap[base],
+					func(a lnwire.ShortChannelID) uint64 {
 						return a.ToUint64()
-			}, scidMap[base]),
+					},
+				),
 			}
-	}, maps.Keys(scidMap))
+		},
+	)
 }

lnrpc/routerrpc/forward_interceptor.go

@@ -3,7 +3,7 @@ package routerrpc
 import (
 	"errors"
 
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lnrpc"

lnrpc/routerrpc/router_backend.go

@@ -16,7 +16,7 @@ import (
 	sphinx "github.com/lightningnetwork/lightning-onion"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/feature"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lntypes"

lnrpc/routerrpc/router_server.go

@@ -16,7 +16,7 @@ import (
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/lightningnetwork/lnd/aliasmgr"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
 	"github.com/lightningnetwork/lnd/lntypes"

lnrpc/walletrpc/walletkit_server.go

@@ -31,7 +31,7 @@ import (
 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/contractcourt"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/labels"
@@ -1145,9 +1145,9 @@ func (w *WalletKit) getWaitingCloseChannel(
 		return nil, err
 	}
 
-	channel := fn.Find(func(c *channeldb.OpenChannel) bool {
+	channel := fn.Find(chans, func(c *channeldb.OpenChannel) bool {
 		return c.FundingOutpoint == chanPoint
-	}, chans)
+	})
 
 	return channel.UnwrapOrErr(errors.New("channel not found"))
 }
@@ -1231,18 +1231,23 @@ func (w *WalletKit) BumpForceCloseFee(_ context.Context,
 	pendingSweeps := maps.Values(inputsMap)
 
 	// Discard everything except for the anchor sweeps.
-	anchors := fn.Filter(func(sweep *sweep.PendingInputResponse) bool {
+	anchors := fn.Filter(
-		// Only filter for anchor inputs because these are the only
+		pendingSweeps,
-		// inputs which can be used to bump a closed unconfirmed
+		func(sweep *sweep.PendingInputResponse) bool {
-		// commitment transaction.
+			// Only filter for anchor inputs because these are the
-		if sweep.WitnessType != input.CommitmentAnchor &&
+			// only inputs which can be used to bump a closed
-			sweep.WitnessType != input.TaprootAnchorSweepSpend {
+			// unconfirmed commitment transaction.
-
+			isCommitAnchor := sweep.WitnessType ==
+				input.CommitmentAnchor
+			isTaprootSweepSpend := sweep.WitnessType ==
+				input.TaprootAnchorSweepSpend
+			if !isCommitAnchor && !isTaprootSweepSpend {
 				return false
 			}
 
 			return commitSet.Contains(sweep.OutPoint.Hash)
-	}, pendingSweeps)
+		},
+	)
 
 	if len(anchors) == 0 {
 		return nil, fmt.Errorf("unable to find pending anchor outputs")
@@ -1754,7 +1759,7 @@ func (w *WalletKit) fundPsbtInternalWallet(account string,
 				return true
 			}
 
-			eligibleUtxos := fn.Filter(filterFn, utxos)
+			eligibleUtxos := fn.Filter(utxos, filterFn)
 
 			// Validate all inputs against our known list of UTXOs
 			// now.

lntest/harness.go

@@ -13,7 +13,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/go-errors/errors"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/kvdb/etcd"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"

lntest/harness_assertion.go

@@ -19,7 +19,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
@@ -270,7 +270,7 @@ func (h *HarnessTest) AssertNumActiveEdges(hn *node.HarnessNode,
 			IncludeUnannounced: includeUnannounced,
 		}
 		resp := hn.RPC.DescribeGraph(req)
-		activeEdges := fn.Filter(filterDisabled, resp.Edges)
+		activeEdges := fn.Filter(resp.Edges, filterDisabled)
 		total := len(activeEdges)
 
 		if total-old == expected {

lntest/miner/miner.go

@@ -17,7 +17,7 @@ import (
 	"github.com/btcsuite/btcd/integration/rpctest"
 	"github.com/btcsuite/btcd/rpcclient"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntest/node"
 	"github.com/lightningnetwork/lnd/lntest/wait"
 	"github.com/stretchr/testify/require"
@@ -296,10 +296,7 @@ func (h *HarnessMiner) AssertTxInMempool(txid chainhash.Hash) *wire.MsgTx {
 			return fmt.Errorf("empty mempool")
 		}
 
-		isEqual := func(memTx chainhash.Hash) bool {
+		result := fn.Find(mempool, fn.Eq(txid))
-			return memTx == txid
-		}
-		result := fn.Find(isEqual, mempool)
 
 		if result.IsNone() {
 			return fmt.Errorf("txid %v not found in "+

lntest/mock/walletcontroller.go

@@ -16,7 +16,7 @@ import (
 	base "github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/wallet/txauthor"
 	"github.com/btcsuite/btcwallet/wtxmgr"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )

lntest/node/state.go

@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
 	"github.com/lightningnetwork/lnd/lntest/rpc"
@@ -324,11 +324,11 @@ func (s *State) updateEdgeStats() {
 
 	req := &lnrpc.ChannelGraphRequest{IncludeUnannounced: true}
 	resp := s.rpc.DescribeGraph(req)
-	s.Edge.Total = len(fn.Filter(filterDisabled, resp.Edges))
+	s.Edge.Total = len(fn.Filter(resp.Edges, filterDisabled))
 
 	req = &lnrpc.ChannelGraphRequest{IncludeUnannounced: false}
 	resp = s.rpc.DescribeGraph(req)
-	s.Edge.Public = len(fn.Filter(filterDisabled, resp.Edges))
+	s.Edge.Public = len(fn.Filter(resp.Edges, filterDisabled))
 }
 
 // updateWalletBalance creates stats for the node's wallet balance.

lnwallet/aux_leaf_store.go

@@ -5,7 +5,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"

lnwallet/aux_resolutions.go

@@ -4,7 +4,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/tlv"

lnwallet/aux_signer.go

@@ -2,7 +2,7 @@ package lnwallet
 
 import (
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"

lnwallet/btcwallet/btcwallet.go

@@ -27,7 +27,7 @@ import (
 	"github.com/btcsuite/btcwallet/wtxmgr"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/blockcache"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"

lnwallet/chainfee/filtermanager.go

@@ -9,7 +9,7 @@ import (
 
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/rpcclient"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 const (

lnwallet/chancloser/aux_closer.go

@@ -4,7 +4,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/tlv"

lnwallet/chancloser/chancloser.go

@@ -12,7 +12,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/htlcswitch"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/labels"

lnwallet/chancloser/chancloser_test.go

@@ -14,7 +14,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"

lnwallet/chancloser/interface.go

@@ -6,7 +6,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet"

lnwallet/chanfunding/canned_assembler.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 )

lnwallet/chanfunding/interface.go

@@ -8,7 +8,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/wtxmgr"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 )
 

lnwallet/chanfunding/psbt_assembler.go

@@ -13,7 +13,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 )

lnwallet/channel.go

@@ -25,7 +25,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
@@ -600,7 +600,7 @@ func (lc *LightningChannel) extractPayDescs(feeRate chainfee.SatPerKWeight,
 
 		htlc := htlc
 
-		auxLeaf := fn.ChainOption(
+		auxLeaf := fn.FlatMapOption(
 			func(l CommitAuxLeaves) input.AuxTapLeaf {
 				leaves := l.OutgoingHtlcLeaves
 				if htlc.Incoming {
@@ -1106,7 +1106,7 @@ func (lc *LightningChannel) logUpdateToPayDesc(logUpdate *channeldb.LogUpdate,
 			feeRate, wireMsg.Amount.ToSatoshis(), remoteDustLimit,
 		)
 		if !isDustRemote {
-			auxLeaf := fn.ChainOption(
+			auxLeaf := fn.FlatMapOption(
 				func(l CommitAuxLeaves) input.AuxTapLeaf {
 					leaves := l.OutgoingHtlcLeaves
 					return leaves[pd.HtlcIndex].AuxTapLeaf
@@ -2088,7 +2088,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 
 	// Since it is the remote breach we are reconstructing, the output
 	// going to us will be a to-remote script with our local params.
-	remoteAuxLeaf := fn.ChainOption(
+	remoteAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.RemoteAuxLeaf
 		},
@@ -2102,7 +2102,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 		return nil, err
 	}
 
-	localAuxLeaf := fn.ChainOption(
+	localAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.LocalAuxLeaf
 		},
@@ -2229,7 +2229,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		br.LocalResolutionBlob = resolveBlob.Option()
+		br.LocalResolutionBlob = resolveBlob.OkToSome()
 	}
 
 	// Similarly, if their balance exceeds the remote party's dust limit,
@@ -2308,7 +2308,7 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		br.RemoteResolutionBlob = resolveBlob.Option()
+		br.RemoteResolutionBlob = resolveBlob.OkToSome()
 	}
 
 	// Finally, with all the necessary data constructed, we can pad the
@@ -2338,7 +2338,7 @@ func createHtlcRetribution(chanState *channeldb.OpenChannel,
 	// We'll generate the original second level witness script now, as
 	// we'll need it if we're revoking an HTLC output on the remote
 	// commitment transaction, and *they* go to the second level.
-	secondLevelAuxLeaf := fn.ChainOption(
+	secondLevelAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) fn.Option[input.AuxTapLeaf] {
 			return fn.MapOption(func(val uint16) input.AuxTapLeaf {
 				idx := input.HtlcIndex(val)
@@ -2366,7 +2366,7 @@ func createHtlcRetribution(chanState *channeldb.OpenChannel,
 	// HTLC script. Otherwise, is this was an outgoing HTLC that we sent,
 	// then from the PoV of the remote commitment state, they're the
 	// receiver of this HTLC.
-	htlcLeaf := fn.ChainOption(
+	htlcLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) fn.Option[input.AuxTapLeaf] {
 			return fn.MapOption(func(val uint16) input.AuxTapLeaf {
 				idx := input.HtlcIndex(val)
@@ -2693,13 +2693,13 @@ type HtlcView struct {
 // AuxOurUpdates returns the outgoing HTLCs as a read-only copy of
 // AuxHtlcDescriptors.
 func (v *HtlcView) AuxOurUpdates() []AuxHtlcDescriptor {
-	return fn.Map(newAuxHtlcDescriptor, v.Updates.Local)
+	return fn.Map(v.Updates.Local, newAuxHtlcDescriptor)
 }
 
 // AuxTheirUpdates returns the incoming HTLCs as a read-only copy of
 // AuxHtlcDescriptors.
 func (v *HtlcView) AuxTheirUpdates() []AuxHtlcDescriptor {
-	return fn.Map(newAuxHtlcDescriptor, v.Updates.Remote)
+	return fn.Map(v.Updates.Remote, newAuxHtlcDescriptor)
 }
 
 // fetchHTLCView returns all the candidate HTLC updates which should be
@@ -2917,9 +2917,9 @@ func (lc *LightningChannel) evaluateHTLCView(view *HtlcView,
 	// The fee rate of our view is always the last UpdateFee message from
 	// the channel's OpeningParty.
 	openerUpdates := view.Updates.GetForParty(lc.channelState.Initiator())
-	feeUpdates := fn.Filter(func(u *paymentDescriptor) bool {
+	feeUpdates := fn.Filter(openerUpdates, func(u *paymentDescriptor) bool {
 		return u.EntryType == FeeUpdate
-	}, openerUpdates)
+	})
 	lastFeeUpdate := fn.Last(feeUpdates)
 	lastFeeUpdate.WhenSome(func(pd *paymentDescriptor) {
 		newView.FeePerKw = chainfee.SatPerKWeight(
@@ -2942,14 +2942,17 @@ func (lc *LightningChannel) evaluateHTLCView(view *HtlcView,
 	for _, party := range parties {
 		// First we run through non-add entries in both logs,
 		// populating the skip sets.
-		resolutions := fn.Filter(func(pd *paymentDescriptor) bool {
+		resolutions := fn.Filter(
+			view.Updates.GetForParty(party),
+			func(pd *paymentDescriptor) bool {
 				switch pd.EntryType {
 				case Settle, Fail, MalformedFail:
 					return true
 				default:
 					return false
 				}
-		}, view.Updates.GetForParty(party))
+			},
+		)
 
 		for _, entry := range resolutions {
 			addEntry, err := lc.fetchParent(
@@ -3002,10 +3005,16 @@ func (lc *LightningChannel) evaluateHTLCView(view *HtlcView,
 	// settled HTLCs, and debiting the chain state balance due to any newly
 	// added HTLCs.
 	for _, party := range parties {
-		liveAdds := fn.Filter(func(pd *paymentDescriptor) bool {
+		liveAdds := fn.Filter(
-			return pd.EntryType == Add &&
+			view.Updates.GetForParty(party),
-				!skip.GetForParty(party).Contains(pd.HtlcIndex)
+			func(pd *paymentDescriptor) bool {
-		}, view.Updates.GetForParty(party))
+				isAdd := pd.EntryType == Add
+				shouldSkip := skip.GetForParty(party).
+					Contains(pd.HtlcIndex)
+
+				return isAdd && !shouldSkip
+			},
+		)
 
 		for _, entry := range liveAdds {
 			// Skip the entries that have already had their add
@@ -3063,7 +3072,7 @@ func (lc *LightningChannel) evaluateHTLCView(view *HtlcView,
 	uncommittedUpdates := lntypes.MapDual(
 		view.Updates,
 		func(us []*paymentDescriptor) []*paymentDescriptor {
-			return fn.Filter(isUncommitted, us)
+			return fn.Filter(us, isUncommitted)
 		},
 	)
 
@@ -3189,7 +3198,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		htlcFee := HtlcTimeoutFee(chanType, feePerKw)
 		outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
-		auxLeaf := fn.ChainOption(
+		auxLeaf := fn.FlatMapOption(
 			func(l CommitAuxLeaves) input.AuxTapLeaf {
 				leaves := l.IncomingHtlcLeaves
 				return leaves[htlc.HtlcIndex].SecondLevelLeaf
@@ -3270,7 +3279,7 @@ func genRemoteHtlcSigJobs(keyRing *CommitmentKeyRing,
 		htlcFee := HtlcSuccessFee(chanType, feePerKw)
 		outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
-		auxLeaf := fn.ChainOption(
+		auxLeaf := fn.FlatMapOption(
 			func(l CommitAuxLeaves) input.AuxTapLeaf {
 				leaves := l.OutgoingHtlcLeaves
 				return leaves[htlc.HtlcIndex].SecondLevelLeaf
@@ -4802,7 +4811,7 @@ func genHtlcSigValidationJobs(chanState *channeldb.OpenChannel,
 				htlcFee := HtlcSuccessFee(chanType, feePerKw)
 				outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
-				auxLeaf := fn.ChainOption(func(
+				auxLeaf := fn.FlatMapOption(func(
 					l CommitAuxLeaves) input.AuxTapLeaf {
 
 					leaves := l.IncomingHtlcLeaves
@@ -4895,7 +4904,7 @@ func genHtlcSigValidationJobs(chanState *channeldb.OpenChannel,
 				htlcFee := HtlcTimeoutFee(chanType, feePerKw)
 				outputAmt := htlc.Amount.ToSatoshis() - htlcFee
 
-				auxLeaf := fn.ChainOption(func(
+				auxLeaf := fn.FlatMapOption(func(
 					l CommitAuxLeaves) input.AuxTapLeaf {
 
 					leaves := l.OutgoingHtlcLeaves
@@ -6766,7 +6775,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, //nolint:funlen
 	// Before we can generate the proper sign descriptor, we'll need to
 	// locate the output index of our non-delayed output on the commitment
 	// transaction.
-	remoteAuxLeaf := fn.ChainOption(
+	remoteAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.RemoteAuxLeaf
 		},
@@ -6870,7 +6879,7 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, //nolint:funlen
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		commitResolution.ResolutionBlob = resolveBlob.Option()
+		commitResolution.ResolutionBlob = resolveBlob.OkToSome()
 	}
 
 	closeSummary := channeldb.ChannelCloseSummary{
@@ -7059,7 +7068,7 @@ func newOutgoingHtlcResolution(signer input.Signer,
 
 	// First, we'll re-generate the script used to send the HTLC to the
 	// remote party within their commitment transaction.
-	auxLeaf := fn.ChainOption(func(l CommitAuxLeaves) input.AuxTapLeaf {
+	auxLeaf := fn.FlatMapOption(func(l CommitAuxLeaves) input.AuxTapLeaf {
 		return l.OutgoingHtlcLeaves[htlc.HtlcIndex].AuxTapLeaf
 	})(auxLeaves)
 	htlcScriptInfo, err := genHtlcScript(
@@ -7149,7 +7158,7 @@ func newOutgoingHtlcResolution(signer input.Signer,
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		resolutionBlob := resolveRes.Option()
+		resolutionBlob := resolveRes.OkToSome()
 
 		return &OutgoingHtlcResolution{
 			Expiry:         htlc.RefundTimeout,
@@ -7171,7 +7180,7 @@ func newOutgoingHtlcResolution(signer input.Signer,
 
 	// With the fee calculated, re-construct the second level timeout
 	// transaction.
-	secondLevelAuxLeaf := fn.ChainOption(
+	secondLevelAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			leaves := l.OutgoingHtlcLeaves
 			return leaves[htlc.HtlcIndex].SecondLevelLeaf
@@ -7366,7 +7375,7 @@ func newOutgoingHtlcResolution(signer input.Signer,
 	if err := resolveRes.Err(); err != nil {
 		return nil, fmt.Errorf("unable to aux resolve: %w", err)
 	}
-	resolutionBlob := resolveRes.Option()
+	resolutionBlob := resolveRes.OkToSome()
 
 	return &OutgoingHtlcResolution{
 		Expiry:          htlc.RefundTimeout,
@@ -7406,7 +7415,7 @@ func newIncomingHtlcResolution(signer input.Signer,
 
 	// First, we'll re-generate the script the remote party used to
 	// send the HTLC to us in their commitment transaction.
-	auxLeaf := fn.ChainOption(func(l CommitAuxLeaves) input.AuxTapLeaf {
+	auxLeaf := fn.FlatMapOption(func(l CommitAuxLeaves) input.AuxTapLeaf {
 		return l.IncomingHtlcLeaves[htlc.HtlcIndex].AuxTapLeaf
 	})(auxLeaves)
 	scriptInfo, err := genHtlcScript(
@@ -7497,7 +7506,7 @@ func newIncomingHtlcResolution(signer input.Signer,
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		resolutionBlob := resolveRes.Option()
+		resolutionBlob := resolveRes.OkToSome()
 
 		return &IncomingHtlcResolution{
 			ClaimOutpoint:  op,
@@ -7507,7 +7516,7 @@ func newIncomingHtlcResolution(signer input.Signer,
 		}, nil
 	}
 
-	secondLevelAuxLeaf := fn.ChainOption(
+	secondLevelAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			leaves := l.IncomingHtlcLeaves
 			return leaves[htlc.HtlcIndex].SecondLevelLeaf
@@ -7707,7 +7716,7 @@ func newIncomingHtlcResolution(signer input.Signer,
 		return nil, fmt.Errorf("unable to aux resolve: %w", err)
 	}
 
-	resolutionBlob := resolveRes.Option()
+	resolutionBlob := resolveRes.OkToSome()
 
 	return &IncomingHtlcResolution{
 		SignedSuccessTx: successTx,
@@ -8011,7 +8020,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel,
 		leaseExpiry = chanState.ThawHeight
 	}
 
-	localAuxLeaf := fn.ChainOption(
+	localAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.LocalAuxLeaf
 		},
@@ -8126,7 +8135,7 @@ func NewLocalForceCloseSummary(chanState *channeldb.OpenChannel,
 			return nil, fmt.Errorf("unable to aux resolve: %w", err)
 		}
 
-		commitResolution.ResolutionBlob = resolveBlob.Option()
+		commitResolution.ResolutionBlob = resolveBlob.OkToSome()
 	}
 
 	// Once the delay output has been found (if it exists), then we'll also

lnwallet/channel_test.go

@@ -25,7 +25,7 @@ import (
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/graph/db/models"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
@@ -730,9 +730,12 @@ func TestCommitHTLCSigCustomRecordSize(t *testing.T) {
 
 		// Replace the default PackSigs implementation to return a
 		// large custom records blob.
-		mockSigner.ExpectedCalls = fn.Filter(func(c *mock.Call) bool {
+		mockSigner.ExpectedCalls = fn.Filter(
+			mockSigner.ExpectedCalls,
+			func(c *mock.Call) bool {
 				return c.Method != "PackSigs"
-		}, mockSigner.ExpectedCalls)
+			},
+		)
 		mockSigner.On("PackSigs", mock.Anything).
 			Return(fn.Ok(fn.Some(largeBlob)))
 	})

lnwallet/commitment.go

@@ -11,7 +11,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
@@ -836,7 +836,7 @@ func (cb *CommitmentBuilder) createUnsignedCommitmentTx(ourBalance,
 			continue
 		}
 
-		auxLeaf := fn.ChainOption(
+		auxLeaf := fn.FlatMapOption(
 			func(leaves input.HtlcAuxLeaves) input.AuxTapLeaf {
 				return leaves[htlc.HtlcIndex].AuxTapLeaf
 			},
@@ -864,7 +864,7 @@ func (cb *CommitmentBuilder) createUnsignedCommitmentTx(ourBalance,
 			continue
 		}
 
-		auxLeaf := fn.ChainOption(
+		auxLeaf := fn.FlatMapOption(
 			func(leaves input.HtlcAuxLeaves) input.AuxTapLeaf {
 				return leaves[htlc.HtlcIndex].AuxTapLeaf
 			},
@@ -1323,7 +1323,7 @@ func findOutputIndexesFromRemote(revocationPreimage *chainhash.Hash,
 
 	// Compute the to_local script. From our PoV, when facing a remote
 	// commitment, the to_local output belongs to them.
-	localAuxLeaf := fn.ChainOption(
+	localAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.LocalAuxLeaf
 		},
@@ -1338,7 +1338,7 @@ func findOutputIndexesFromRemote(revocationPreimage *chainhash.Hash,
 
 	// Compute the to_remote script. From our PoV, when facing a remote
 	// commitment, the to_remote output belongs to us.
-	remoteAuxLeaf := fn.ChainOption(
+	remoteAuxLeaf := fn.FlatMapOption(
 		func(l CommitAuxLeaves) input.AuxTapLeaf {
 			return l.RemoteAuxLeaf
 		},

lnwallet/commitment_chain.go

@@ -1,7 +1,7 @@
 package lnwallet
 
 import (
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 )
 
 // commitmentChain represents a chain of unrevoked commitments. The tail of the

lnwallet/config.go

@@ -5,7 +5,7 @@ import (
 	"github.com/btcsuite/btcwallet/wallet"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"

lnwallet/interface.go

@@ -19,7 +19,7 @@ import (
 	base "github.com/btcsuite/btcwallet/wallet"
 	"github.com/btcsuite/btcwallet/wallet/txauthor"
 	"github.com/btcsuite/btcwallet/wtxmgr"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/lnwallet/chanvalidate"

lnwallet/mock.go

@@ -18,7 +18,7 @@ import (
 	"github.com/btcsuite/btcwallet/wtxmgr"
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwallet/chainfee"
 	"github.com/lightningnetwork/lnd/tlv"

lnwallet/musig_session.go

@@ -11,7 +11,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwire"

lnwallet/reservation.go

@@ -12,7 +12,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"

lnwallet/rpcwallet/rpcwallet.go

@@ -22,7 +22,7 @@ import (
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/waddrmgr"
 	basewallet "github.com/btcsuite/btcwallet/wallet"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lncfg"

lnwallet/test/test_interface.go

@@ -34,7 +34,7 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	"github.com/lightningnetwork/lnd/chainntnfs/btcdnotify"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/kvdb"

lnwallet/test_utils.go

@@ -16,7 +16,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"

lnwallet/transactions_test.go

@@ -21,7 +21,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
-	"github.com/lightningnetwork/lnd/fn"
+	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lntypes"