multi: add trace log outputs

This commit adds a couple of trace outputs that were helpful in finding
two bugs fixed in this series of commits.

We also increase the number of levels the spew logger is allowed to
print, so we can see a bit more. We need this limit to avoid endless
loops in self-referencing structs such as proofs.

tapchannel/commitment.go

@@ -763,6 +763,13 @@ func CreateAllocations(chanState lnwallet.AuxChanState, ourBalance,
 		// asset level, NOT for the BTC level.
 		tweakedTree := TweakHtlcTree(htlcTree, htlc.HtlcIndex)
 
+		log.Tracef("Tweaking HTLC script key with index %d: internal "+
+			"key %x -> %x, script key %x -> %x", htlc.HtlcIndex,
+			htlcTree.InternalKey.SerializeCompressed(),
+			tweakedTree.InternalKey.SerializeCompressed(),
+			schnorr.SerializePubKey(htlcTree.TaprootKey),
+			schnorr.SerializePubKey(tweakedTree.TaprootKey))
+
 		allocations = append(allocations, &Allocation{
 			Type:           allocType,
 			Amount:         rfqmsg.Sum(htlc.AssetBalances),
@@ -1288,6 +1295,13 @@ func createSecondLevelHtlcAllocations(chanType channeldb.ChannelType,
 	// the BTC level.
 	tweakedTree := TweakHtlcTree(htlcTree, htlcIndex)
 
+	log.Tracef("Tweaking second level HTLC script key with index %d: "+
+		"internal key %x -> %x, script key %x -> %x", htlcIndex,
+		htlcTree.InternalKey.SerializeCompressed(),
+		tweakedTree.InternalKey.SerializeCompressed(),
+		schnorr.SerializePubKey(htlcTree.TaprootKey),
+		schnorr.SerializePubKey(tweakedTree.TaprootKey))
+
 	allocations := []*Allocation{{
 		Type: SecondLevelHtlcAllocation,
 		// If we're making the second-level transaction just to sign,

tapchannel/log.go

@@ -17,7 +17,7 @@ var log = btclog.Disabled
 // to 4 levels, so it can safely be used for things that contain an MS-SMT tree.
 var limitSpewer = &spew.ConfigState{
 	Indent:   "  ",
-	MaxDepth: 5,
+	MaxDepth: 7,
 }
 
 // DisableLog disables all library log output.  Logging output is disabled

tapsend/send.go

@@ -19,6 +19,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btclog"
+	"github.com/davecgh/go-spew/spew"
 	"github.com/lightninglabs/lndclient"
 	"github.com/lightninglabs/taproot-assets/address"
 	"github.com/lightninglabs/taproot-assets/asset"
@@ -974,6 +975,9 @@ func CreateTaprootSignature(vIn *tappsbt.VInput, virtualTx *wire.MsgTx,
 			"from virtual transaction packet")
 	}
 
+	log.Tracef("Signing virtual TX with descriptor %v",
+		spew.Sdump(spendDesc))
+
 	sig, err := txSigner.SignVirtualTx(&spendDesc, virtualTx, prevOut)
 	if err != nil {
 		return nil, err