multi: turn VInput's proof into actual struct

Now that we've resolved the circular package dependency between the
proof and tappsbt packages, we can finally use the *proof.Proof type
directly for the packet's input proof (and later the output's proof
suffix).

Author: guggero

tapfreighter/wallet.go

@@ -514,7 +514,7 @@ func (f *AssetWallet) passiveAssetVPacket(passiveAsset *asset.Asset,
 
 	// Set the input asset. The input asset proof is not provided as it is
 	// not needed for the re-anchoring process.
-	vPacket.SetInputAsset(0, inputAsset, nil)
+	vPacket.SetInputAsset(0, inputAsset)
 
 	return vPacket
 }
@@ -999,7 +999,7 @@ func (f *AssetWallet) setVPacketInputs(ctx context.Context,
 			return nil, fmt.Errorf("cannot decode proof for input "+
 				"asset: %w", err)
 		}
-		inputProof, err := inputProofFile.RawLastProof()
+		inputProof, err := inputProofFile.LastProof()
 		if err != nil {
 			return nil, fmt.Errorf("cannot get last proof for "+
 				"input asset: %w", err)
@@ -1037,11 +1037,12 @@ func (f *AssetWallet) setVPacketInputs(ctx context.Context,
 					inTrBip32Derivation,
 				},
 			},
+			Proof: inputProof,
 			PInput: psbt.PInput{
 				SighashType: txscript.SigHashDefault,
 			},
 		}
-		vPkt.SetInputAsset(idx, assetInput.Asset, inputProof)
+		vPkt.SetInputAsset(idx, assetInput.Asset)
 
 		inputCommitments[idx] = assetInput.Commitment
 	}
@@ -1127,10 +1128,10 @@ func (f *AssetWallet) SignVirtualPacket(vPkt *tappsbt.VPacket,
 // verifyInclusionProof verifies that the given virtual input's asset is
 // actually committed in the anchor transaction.
 func verifyInclusionProof(vIn *tappsbt.VInput) error {
-	proofReader := bytes.NewReader(vIn.Proof())
-	assetProof := &proof.Proof{}
-	if err := assetProof.Decode(proofReader); err != nil {
-		return fmt.Errorf("unable to decode asset proof: %w", err)
+	assetProof := vIn.Proof
+
+	if assetProof == nil {
+		return fmt.Errorf("input proof is nil")
 	}
 
 	// Before we look at the inclusion proof, we'll make sure that the input
@@ -1143,8 +1144,7 @@ func verifyInclusionProof(vIn *tappsbt.VInput) error {
 
 	if op.Hash != anchorTxHash {
 		return fmt.Errorf("proof anchor tx hash %v doesn't match "+
-			"input anchor outpoint %v in proof %x", anchorTxHash,
-			op.Hash, vIn.Proof())
+			"input anchor outpoint %v", anchorTxHash, op.Hash)
 	}
 	if op.Index >= uint32(len(assetProof.AnchorTx.TxOut)) {
 		return fmt.Errorf("input anchor outpoint index out of range")
@@ -1153,8 +1153,8 @@ func verifyInclusionProof(vIn *tappsbt.VInput) error {
 	anchorTxOut := assetProof.AnchorTx.TxOut[op.Index]
 	if !bytes.Equal(anchorTxOut.PkScript, vIn.Anchor.PkScript) {
 		return fmt.Errorf("proof anchor tx pk script %x doesn't "+
-			"match input anchor script %x in proof %x",
-			anchorTxOut.PkScript, vIn.Anchor.PkScript, vIn.Proof())
+			"match input anchor script %x", anchorTxOut.PkScript,
+			vIn.Anchor.PkScript)
 	}
 
 	anchorKey, err := proof.ExtractTaprootKeyFromScript(vIn.Anchor.PkScript)

tappsbt/address.go

@@ -150,7 +150,7 @@ func OwnershipProofPacket(ownedAsset *asset.Asset,
 		}},
 		ChainParams: chainParams,
 	}
-	vPkt.SetInputAsset(0, ownedAsset, nil)
+	vPkt.SetInputAsset(0, ownedAsset)
 
 	return vPkt
 }

tappsbt/decode.go

@@ -15,6 +15,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/address"
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/commitment"
+	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
@@ -168,7 +169,7 @@ func (i *VInput) decode(pIn psbt.PInput) error {
 		decoder: assetDecoder(&i.asset),
 	}, {
 		key:     PsbtKeyTypeInputTapAssetProof,
-		decoder: tlvDecoder(&i.proof, tlv.DVarBytes),
+		decoder: proofDecoder(&i.Proof),
 	}}
 
 	for idx := range mapping {
@@ -309,7 +310,7 @@ func (o *VOutput) decode(pOut psbt.POutput, txOut *wire.TxOut) error {
 	return nil
 }
 
-// tlvDecoder returns a function that encodes the given byte slice using the
+// tlvDecoder returns a function that decodes the given byte slice using the
 // given TLV tlvDecoder.
 func tlvDecoder(val any, dec tlv.Decoder) decoderFunc {
 	return func(_, byteVal []byte) error {
@@ -326,6 +327,20 @@ func tlvDecoder(val any, dec tlv.Decoder) decoderFunc {
 	}
 }
 
+// proofDecoder returns a decoder function that can handle nil proofs.
+func proofDecoder(p **proof.Proof) decoderFunc {
+	return func(key, byteVal []byte) error {
+		if len(byteVal) == 0 {
+			return nil
+		}
+
+		if *p == nil {
+			*p = &proof.Proof{}
+		}
+		return (*p).Decode(bytes.NewReader(byteVal))
+	}
+}
+
 // assetDecoder returns a decoder function that can handle nil assets.
 func assetDecoder(a **asset.Asset) decoderFunc {
 	return func(key, byteVal []byte) error {

tappsbt/encode.go

@@ -15,6 +15,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/commitment"
 	"github.com/lightninglabs/taproot-assets/fn"
+	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
@@ -181,7 +182,7 @@ func (i *VInput) encode() (psbt.PInput, error) {
 		},
 		{
 			key:     PsbtKeyTypeInputTapAssetProof,
-			encoder: tlvEncoder(&i.proof, tlv.EVarBytes),
+			encoder: proofEncoder(i.Proof),
 		},
 	}
 
@@ -336,6 +337,28 @@ func pubKeyEncoder(pubKey *btcec.PublicKey) encoderFunc {
 	return tlvEncoder(&pubKey, tlv.EPubKey)
 }
 
+// proofEncoder is an encoder that does nothing if the given proof is nil.
+func proofEncoder(p *proof.Proof) encoderFunc {
+	return func(key []byte) ([]*customPsbtField, error) {
+		if p == nil {
+			return nil, nil
+		}
+
+		var buf bytes.Buffer
+		err := p.Encode(&buf)
+		if err != nil {
+			return nil, err
+		}
+
+		return []*customPsbtField{
+			{
+				Key:   fn.CopySlice(key),
+				Value: buf.Bytes(),
+			},
+		}, nil
+	}
+}
+
 // assetEncoder is an encoder that does nothing if the given asset is nil.
 func assetEncoder(a *asset.Asset) encoderFunc {
 	if a == nil {

tappsbt/interface.go

@@ -13,6 +13,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/commitment"
 	"github.com/lightninglabs/taproot-assets/fn"
+	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
@@ -156,12 +157,11 @@ type VPacket struct {
 }
 
 // SetInputAsset sets the input asset that is being spent.
-func (p *VPacket) SetInputAsset(index int, a *asset.Asset, proof []byte) {
+func (p *VPacket) SetInputAsset(index int, a *asset.Asset) {
 	if index >= len(p.Inputs) {
 		p.Inputs = append(p.Inputs, &VInput{})
 	}
 	p.Inputs[index].asset = a.Copy()
-	p.Inputs[index].proof = proof
 	p.Inputs[index].serializeScriptKey(
 		a.ScriptKey, p.ChainParams.HDCoinType,
 	)
@@ -309,23 +309,16 @@ type VInput struct {
 	// input struct for the signing to work correctly.
 	asset *asset.Asset
 
-	// proof is the proof blob that proves the asset being spent was
-	// committed to in the anchor transaction above. This cannot be of type
-	// proof.Proof directly because that would cause a circular dependency.
-	proof []byte
+	// Proof is a transition proof that proves the asset being spent was
+	// committed to in the anchor transaction above.
+	Proof *proof.Proof
 }
 
 // Asset returns the input's asset that's being spent.
 func (i *VInput) Asset() *asset.Asset {
 	return i.asset
 }
 
-// Proof returns the proof blob that the asset being spent was committed to in
-// the anchor transaction.
-func (i *VInput) Proof() []byte {
-	return i.proof
-}
-
 // serializeScriptKey serializes the input asset's script key as the PSBT
 // derivation information on the virtual input.
 func (i *VInput) serializeScriptKey(key asset.ScriptKey, coinType uint32) {

tappsbt/mock.go

@@ -1,23 +1,39 @@
 package tappsbt
 
 import (
+	"bytes"
 	"encoding/hex"
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/btcutil/psbt"
 	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
 	"github.com/lightninglabs/taproot-assets/address"
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/commitment"
 	"github.com/lightninglabs/taproot-assets/internal/test"
+	"github.com/lightninglabs/taproot-assets/proof"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/stretchr/testify/require"
 )
 
+const (
+	// testDataFileName is the name of the directory with the test data.
+	testDataFileName = "testdata"
+)
+
 var (
 	testParams = &address.MainNetTap
+
+	// Block 100002 with 9 transactions on bitcoin mainnet.
+	oddTxBlockHexFileName = filepath.Join(
+		testDataFileName, "odd-block.hex",
+	)
 )
 
 // RandPacket generates a random virtual packet for testing purposes.
@@ -68,6 +84,22 @@ func RandPacket(t testing.TB) *VPacket {
 		txscript.NewTapBranch(leaf1, leaf1),
 	)
 
+	oddTxBlockHex, err := os.ReadFile(oddTxBlockHexFileName)
+	require.NoError(t, err)
+
+	oddTxBlockBytes, err := hex.DecodeString(
+		strings.Trim(string(oddTxBlockHex), "\n"),
+	)
+	require.NoError(t, err)
+
+	var oddTxBlock wire.MsgBlock
+	err = oddTxBlock.Deserialize(bytes.NewReader(oddTxBlockBytes))
+	require.NoError(t, err)
+
+	inputProof := proof.RandProof(
+		t, testAsset.Genesis, inputScriptKey.PubKey, oddTxBlock, 1, 0,
+	)
+
 	vPacket := &VPacket{
 		Inputs: []*VInput{{
 			PrevID: asset.PrevID{
@@ -85,12 +117,15 @@ func RandPacket(t testing.TB) *VPacket {
 				Bip32Derivation:   bip32Derivations,
 				TrBip32Derivation: trBip32Derivations,
 			},
+			Proof: &inputProof,
 		}, {
 			// Empty input.
 		}},
 		Outputs: []*VOutput{{
-			Amount:                             123,
-			AssetVersion:                       asset.Version(test.RandIntn(2)),
+			Amount: 123,
+			AssetVersion: asset.Version(
+				test.RandIntn(2),
+			),
 			Type:                               TypeSplitRoot,
 			Interactive:                        true,
 			AnchorOutputIndex:                  0,
@@ -102,8 +137,10 @@ func RandPacket(t testing.TB) *VPacket {
 			SplitAsset:                         testOutputAsset,
 			AnchorOutputTapscriptSibling:       testPreimage1,
 		}, {
-			Amount:                             345,
-			AssetVersion:                       asset.Version(test.RandIntn(2)),
+			Amount: 345,
+			AssetVersion: asset.Version(
+				test.RandIntn(2),
+			),
 			Type:                               TypeSplitRoot,
 			Interactive:                        false,
 			AnchorOutputIndex:                  1,
@@ -116,7 +153,7 @@ func RandPacket(t testing.TB) *VPacket {
 		}},
 		ChainParams: testParams,
 	}
-	vPacket.SetInputAsset(0, testAsset, []byte("this is a proof"))
+	vPacket.SetInputAsset(0, testAsset)
 
 	return vPacket
 }
@@ -207,7 +244,6 @@ func NewTestFromVInput(t testing.TB, i *VInput) *TestVInput {
 		TrMerkleRoot:  hex.EncodeToString(i.TaprootMerkleRoot),
 		PrevID:        asset.NewTestFromPrevID(&i.PrevID),
 		Anchor:        NewTestFromAnchor(&i.Anchor),
-		Proof:         hex.EncodeToString(i.proof),
 	}
 
 	for idx := range i.Bip32Derivation {
@@ -230,6 +266,10 @@ func NewTestFromVInput(t testing.TB, i *VInput) *TestVInput {
 		ti.Asset = asset.NewTestFromAsset(t, i.asset)
 	}
 
+	if i.Proof != nil {
+		ti.Proof = proof.NewTestFromProof(t, i.Proof)
+	}
+
 	return ti
 }
 
@@ -241,7 +281,7 @@ type TestVInput struct {
 	PrevID            *asset.TestPrevID        `json:"prev_id"`
 	Anchor            *TestAnchor              `json:"anchor"`
 	Asset             *asset.TestAsset         `json:"asset"`
-	Proof             string                   `json:"proof"`
+	Proof             *proof.TestProof         `json:"proof"`
 }
 
 func (ti *TestVInput) ToVInput(t testing.TB) *VInput {
@@ -254,7 +294,6 @@ func (ti *TestVInput) ToVInput(t testing.TB) *VInput {
 		},
 		PrevID: *ti.PrevID.ToPrevID(t),
 		Anchor: *ti.Anchor.ToAnchor(t),
-		proof:  test.ParseHex(t, ti.Proof),
 	}
 
 	for idx := range ti.Bip32Derivation {
@@ -281,6 +320,10 @@ func (ti *TestVInput) ToVInput(t testing.TB) *VInput {
 		require.NoError(t, err)
 	}
 
+	if ti.Proof != nil {
+		vi.Proof = ti.Proof.ToProof(t)
+	}
+
 	return vi
 }
 

tappsbt/testdata/odd-block.hex

@@ -0,0 +1 @@
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