all: define constructor for BlobSidecar (#32213)

The main purpose of this change is to enforce the version setting when
constructing the blobSidecar, avoiding creating sidecar with wrong/default 
version tag.

beacon/engine/types_test.go

@@ -34,21 +34,13 @@ func TestBlobs(t *testing.T) {
 	header := types.Header{}
 	block := types.NewBlock(&header, &types.Body{}, nil, nil)
 
-	sidecarWithoutCellProofs := &types.BlobTxSidecar{
-		Blobs:       []kzg4844.Blob{*emptyBlob},
-		Commitments: []kzg4844.Commitment{emptyBlobCommit},
-		Proofs:      []kzg4844.Proof{emptyBlobProof},
-	}
+	sidecarWithoutCellProofs := types.NewBlobTxSidecar(types.BlobSidecarVersion0, []kzg4844.Blob{*emptyBlob}, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof})
 	env := BlockToExecutableData(block, common.Big0, []*types.BlobTxSidecar{sidecarWithoutCellProofs}, nil)
 	if len(env.BlobsBundle.Proofs) != 1 {
 		t.Fatalf("Expect 1 proof in blobs bundle, got %v", len(env.BlobsBundle.Proofs))
 	}
 
-	sidecarWithCellProofs := &types.BlobTxSidecar{
-		Blobs:       []kzg4844.Blob{*emptyBlob},
-		Commitments: []kzg4844.Commitment{emptyBlobCommit},
-		Proofs:      emptyCellProof,
-	}
+	sidecarWithCellProofs := types.NewBlobTxSidecar(types.BlobSidecarVersion0, []kzg4844.Blob{*emptyBlob}, []kzg4844.Commitment{emptyBlobCommit}, emptyCellProof)
 	env = BlockToExecutableData(block, common.Big0, []*types.BlobTxSidecar{sidecarWithCellProofs}, nil)
 	if len(env.BlobsBundle.Proofs) != 128 {
 		t.Fatalf("Expect 128 proofs in blobs bundle, got %v", len(env.BlobsBundle.Proofs))

cmd/devp2p/internal/ethtest/suite.go

@@ -879,11 +879,7 @@ func makeSidecar(data ...byte) *types.BlobTxSidecar {
 		commitments = append(commitments, c)
 		proofs = append(proofs, p)
 	}
-	return &types.BlobTxSidecar{
-		Blobs:       blobs,
-		Commitments: commitments,
-		Proofs:      proofs,
-	}
+	return types.NewBlobTxSidecar(types.BlobSidecarVersion0, blobs, commitments, proofs)
 }
 
 func (s *Suite) makeBlobTxs(count, blobs int, discriminator byte) (txs types.Transactions) {
@@ -988,14 +984,10 @@ func (s *Suite) TestBlobViolations(t *utesting.T) {
 // data has been modified to produce a different commitment hash.
 func mangleSidecar(tx *types.Transaction) *types.Transaction {
 	sidecar := tx.BlobTxSidecar()
-	copy := types.BlobTxSidecar{
-		Blobs:       append([]kzg4844.Blob{}, sidecar.Blobs...),
-		Commitments: append([]kzg4844.Commitment{}, sidecar.Commitments...),
-		Proofs:      append([]kzg4844.Proof{}, sidecar.Proofs...),
-	}
+	cpy := sidecar.Copy()
 	// zero the first commitment to alter the sidecar hash
-	copy.Commitments[0] = kzg4844.Commitment{}
-	return tx.WithBlobTxSidecar(&copy)
+	cpy.Commitments[0] = kzg4844.Commitment{}
+	return tx.WithBlobTxSidecar(cpy)
 }
 
 func (s *Suite) TestBlobTxWithoutSidecar(t *utesting.T) {

core/txpool/blobpool/blobpool_test.go

@@ -238,11 +238,7 @@ func makeMultiBlobTx(nonce uint64, gasTipCap uint64, gasFeeCap uint64, blobFeeCa
 		BlobFeeCap: uint256.NewInt(blobFeeCap),
 		BlobHashes: blobHashes,
 		Value:      uint256.NewInt(100),
-		Sidecar: &types.BlobTxSidecar{
-			Blobs:       blobs,
-			Commitments: commitments,
-			Proofs:      proofs,
-		},
+		Sidecar:    types.NewBlobTxSidecar(types.BlobSidecarVersion0, blobs, commitments, proofs),
 	}
 	return types.MustSignNewTx(key, types.LatestSigner(params.MainnetChainConfig), blobtx)
 }
@@ -265,11 +261,7 @@ func makeUnsignedTxWithTestBlob(nonce uint64, gasTipCap uint64, gasFeeCap uint64
 		BlobFeeCap: uint256.NewInt(blobFeeCap),
 		BlobHashes: []common.Hash{testBlobVHashes[blobIdx]},
 		Value:      uint256.NewInt(100),
-		Sidecar: &types.BlobTxSidecar{
-			Blobs:       []kzg4844.Blob{*testBlobs[blobIdx]},
-			Commitments: []kzg4844.Commitment{testBlobCommits[blobIdx]},
-			Proofs:      []kzg4844.Proof{testBlobProofs[blobIdx]},
-		},
+		Sidecar:    types.NewBlobTxSidecar(types.BlobSidecarVersion0, []kzg4844.Blob{*testBlobs[blobIdx]}, []kzg4844.Commitment{testBlobCommits[blobIdx]}, []kzg4844.Proof{testBlobProofs[blobIdx]}),
 	}
 }
 

core/txpool/validation.go

@@ -185,7 +185,7 @@ func validateBlobTx(tx *types.Transaction, head *types.Header, opts *ValidationO
 }
 
 func validateBlobSidecarLegacy(sidecar *types.BlobTxSidecar, hashes []common.Hash) error {
-	if sidecar.Version != 0 {
+	if sidecar.Version != types.BlobSidecarVersion0 {
 		return fmt.Errorf("invalid sidecar version pre-osaka: %v", sidecar.Version)
 	}
 	if len(sidecar.Proofs) != len(hashes) {
@@ -200,7 +200,7 @@ func validateBlobSidecarLegacy(sidecar *types.BlobTxSidecar, hashes []common.Has
 }
 
 func validateBlobSidecarOsaka(sidecar *types.BlobTxSidecar, hashes []common.Hash) error {
-	if sidecar.Version != 1 {
+	if sidecar.Version != types.BlobSidecarVersion1 {
 		return fmt.Errorf("invalid sidecar version post-osaka: %v", sidecar.Version)
 	}
 	if len(sidecar.Proofs) != len(hashes)*kzg4844.CellProofsPerBlob {

core/types/tx_blob.go

@@ -31,6 +31,18 @@ import (
 	"github.com/holiman/uint256"
 )
 
+const (
+	// BlobSidecarVersion0 includes a single proof for verifying the entire blob
+	// against its commitment. Used when the full blob is available and needs to
+	// be checked as a whole.
+	BlobSidecarVersion0 = byte(0)
+
+	// BlobSidecarVersion1 includes multiple cell proofs for verifying specific
+	// blob elements (cells). Used in scenarios like data availability sampling,
+	// where only portions of the blob are verified individually.
+	BlobSidecarVersion1 = byte(1)
+)
+
 // BlobTx represents an EIP-4844 transaction.
 type BlobTx struct {
 	ChainID    *uint256.Int
@@ -63,6 +75,16 @@ type BlobTxSidecar struct {
 	Proofs      []kzg4844.Proof      // Proofs needed by the blob pool
 }
 
+// NewBlobTxSidecar initialises the BlobTxSidecar object with the provided parameters.
+func NewBlobTxSidecar(version byte, blobs []kzg4844.Blob, commitments []kzg4844.Commitment, proofs []kzg4844.Proof) *BlobTxSidecar {
+	return &BlobTxSidecar{
+		Version:     version,
+		Blobs:       blobs,
+		Commitments: commitments,
+		Proofs:      proofs,
+	}
+}
+
 // BlobHashes computes the blob hashes of the given blobs.
 func (sc *BlobTxSidecar) BlobHashes() []common.Hash {
 	hasher := sha256.New()
@@ -76,7 +98,7 @@ func (sc *BlobTxSidecar) BlobHashes() []common.Hash {
 // CellProofsAt returns the cell proofs for blob with index idx.
 // This method is only valid for sidecars with version 1.
 func (sc *BlobTxSidecar) CellProofsAt(idx int) ([]kzg4844.Proof, error) {
-	if sc.Version != 1 {
+	if sc.Version != BlobSidecarVersion1 {
 		return nil, fmt.Errorf("cell proof unsupported, version: %d", sc.Version)
 	}
 	if idx < 0 || idx >= len(sc.Blobs) {
@@ -89,6 +111,25 @@ func (sc *BlobTxSidecar) CellProofsAt(idx int) ([]kzg4844.Proof, error) {
 	return sc.Proofs[index : index+kzg4844.CellProofsPerBlob], nil
 }
 
+// ToV1 converts the BlobSidecar to version 1, attaching the cell proofs.
+func (sc *BlobTxSidecar) ToV1() error {
+	if sc.Version == BlobSidecarVersion1 {
+		return nil
+	}
+	if sc.Version == BlobSidecarVersion0 {
+		sc.Proofs = make([]kzg4844.Proof, 0, len(sc.Blobs)*kzg4844.CellProofsPerBlob)
+		for _, blob := range sc.Blobs {
+			cellProofs, err := kzg4844.ComputeCellProofs(&blob)
+			if err != nil {
+				return err
+			}
+			sc.Proofs = append(sc.Proofs, cellProofs...)
+		}
+		sc.Version = BlobSidecarVersion1
+	}
+	return nil
+}
+
 // encodedSize computes the RLP size of the sidecar elements. This does NOT return the
 // encoded size of the BlobTxSidecar, it's just a helper for tx.Size().
 func (sc *BlobTxSidecar) encodedSize() uint64 {
@@ -121,6 +162,19 @@ func (sc *BlobTxSidecar) ValidateBlobCommitmentHashes(hashes []common.Hash) erro
 	return nil
 }
 
+// Copy returns a deep-copied BlobTxSidecar object.
+func (sc *BlobTxSidecar) Copy() *BlobTxSidecar {
+	return &BlobTxSidecar{
+		Version: sc.Version,
+
+		// The element of these slice is fix-size byte array,
+		// therefore slices.Clone will actually deep copy by value.
+		Blobs:       slices.Clone(sc.Blobs),
+		Commitments: slices.Clone(sc.Commitments),
+		Proofs:      slices.Clone(sc.Proofs),
+	}
+}
+
 // blobTxWithBlobs represents blob tx with its corresponding sidecar.
 // This is an interface because sidecars are versioned.
 type blobTxWithBlobs interface {
@@ -148,7 +202,7 @@ func (btx *blobTxWithBlobsV0) tx() *BlobTx {
 }
 
 func (btx *blobTxWithBlobsV0) assign(sc *BlobTxSidecar) error {
-	sc.Version = 0
+	sc.Version = BlobSidecarVersion0
 	sc.Blobs = btx.Blobs
 	sc.Commitments = btx.Commitments
 	sc.Proofs = btx.Proofs
@@ -160,10 +214,10 @@ func (btx *blobTxWithBlobsV1) tx() *BlobTx {
 }
 
 func (btx *blobTxWithBlobsV1) assign(sc *BlobTxSidecar) error {
-	if btx.Version != 1 {
+	if btx.Version != BlobSidecarVersion1 {
 		return fmt.Errorf("unsupported blob tx version %d", btx.Version)
 	}
-	sc.Version = 1
+	sc.Version = BlobSidecarVersion1
 	sc.Blobs = btx.Blobs
 	sc.Commitments = btx.Commitments
 	sc.Proofs = btx.Proofs
@@ -217,12 +271,7 @@ func (tx *BlobTx) copy() TxData {
 		cpy.S.Set(tx.S)
 	}
 	if tx.Sidecar != nil {
-		cpy.Sidecar = &BlobTxSidecar{
-			Version:     tx.Sidecar.Version,
-			Blobs:       slices.Clone(tx.Sidecar.Blobs),
-			Commitments: slices.Clone(tx.Sidecar.Commitments),
-			Proofs:      slices.Clone(tx.Sidecar.Proofs),
-		}
+		cpy.Sidecar = tx.Sidecar.Copy()
 	}
 	return cpy
 }
@@ -280,7 +329,7 @@ func (tx *BlobTx) encode(b *bytes.Buffer) error {
 	case tx.Sidecar == nil:
 		return rlp.Encode(b, tx)
 
-	case tx.Sidecar.Version == 0:
+	case tx.Sidecar.Version == BlobSidecarVersion0:
 		return rlp.Encode(b, &blobTxWithBlobsV0{
 			BlobTx:      tx,
 			Blobs:       tx.Sidecar.Blobs,
@@ -288,7 +337,7 @@ func (tx *BlobTx) encode(b *bytes.Buffer) error {
 			Proofs:      tx.Sidecar.Proofs,
 		})
 
-	case tx.Sidecar.Version == 1:
+	case tx.Sidecar.Version == BlobSidecarVersion1:
 		return rlp.Encode(b, &blobTxWithBlobsV1{
 			BlobTx:      tx,
 			Version:     tx.Sidecar.Version,

core/types/tx_blob_test.go

@@ -87,11 +87,7 @@ func createEmptyBlobTx(key *ecdsa.PrivateKey, withSidecar bool) *Transaction {
 }
 
 func createEmptyBlobTxInner(withSidecar bool) *BlobTx {
-	sidecar := &BlobTxSidecar{
-		Blobs:       []kzg4844.Blob{*emptyBlob},
-		Commitments: []kzg4844.Commitment{emptyBlobCommit},
-		Proofs:      []kzg4844.Proof{emptyBlobProof},
-	}
+	sidecar := NewBlobTxSidecar(BlobSidecarVersion0, []kzg4844.Blob{*emptyBlob}, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof})
 	blobtx := &BlobTx{
 		ChainID:    uint256.NewInt(1),
 		Nonce:      5,

eth/catalyst/api.go

@@ -527,10 +527,10 @@ func (api *ConsensusAPI) GetBlobsV2(hashes []common.Hash) ([]*engine.BlobAndProo
 	if len(hashes) > 128 {
 		return nil, engine.TooLargeRequest.With(fmt.Errorf("requested blob count too large: %v", len(hashes)))
 	}
-
 	available := api.eth.BlobTxPool().AvailableBlobs(hashes)
 	getBlobsRequestedCounter.Inc(int64(len(hashes)))
 	getBlobsAvailableCounter.Inc(int64(available))
+
 	// Optimization: check first if all blobs are available, if not, return empty response
 	if available != len(hashes) {
 		getBlobsV2RequestMiss.Inc(1)
@@ -557,7 +557,7 @@ func (api *ConsensusAPI) GetBlobsV2(hashes []common.Hash) ([]*engine.BlobAndProo
 			// not found, return empty response
 			return nil, nil
 		}
-		if sidecar.Version != 1 {
+		if sidecar.Version != types.BlobSidecarVersion1 {
 			log.Info("GetBlobs queried V0 transaction: index %v, blobhashes %v", index, sidecar.BlobHashes())
 			return nil, nil
 		}
@@ -566,9 +566,7 @@ func (api *ConsensusAPI) GetBlobsV2(hashes []common.Hash) ([]*engine.BlobAndProo
 			if idxes, ok := index[hash]; ok {
 				proofs, err := sidecar.CellProofsAt(bIdx)
 				if err != nil {
-					// TODO @rjl @marius we should return an error
-					log.Info("Failed to get cell proof", "err", err)
-					return nil, nil
+					return nil, engine.InvalidParams.With(err)
 				}
 				var cellProofs []hexutil.Bytes
 				for _, proof := range proofs {

eth/catalyst/api_test.go

@@ -1511,13 +1511,8 @@ func TestBlockToPayloadWithBlobs(t *testing.T) {
 	}
 
 	txs = append(txs, types.NewTx(&inner))
-	sidecars := []*types.BlobTxSidecar{
-		{
-			Blobs:       make([]kzg4844.Blob, 1),
-			Commitments: make([]kzg4844.Commitment, 1),
-			Proofs:      make([]kzg4844.Proof, 1),
-		},
-	}
+	sidecar := types.NewBlobTxSidecar(types.BlobSidecarVersion0, make([]kzg4844.Blob, 1), make([]kzg4844.Commitment, 1), make([]kzg4844.Proof, 1))
+	sidecars := []*types.BlobTxSidecar{sidecar}
 
 	block := types.NewBlock(&header, &types.Body{Transactions: txs}, nil, trie.NewStackTrie(nil))
 	envelope := engine.BlockToExecutableData(block, nil, sidecars, nil)

eth/protocols/eth/handler_test.go

@@ -661,11 +661,7 @@ func testGetPooledTransaction(t *testing.T, blobTx bool) {
 			To:         testAddr,
 			BlobHashes: []common.Hash{emptyBlobHash},
 			BlobFeeCap: uint256.MustFromBig(common.Big1),
-			Sidecar: &types.BlobTxSidecar{
-				Blobs:       emptyBlobs,
-				Commitments: []kzg4844.Commitment{emptyBlobCommit},
-				Proofs:      []kzg4844.Proof{emptyBlobProof},
-			},
+			Sidecar:    types.NewBlobTxSidecar(types.BlobSidecarVersion0, emptyBlobs, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof}),
 		})
 		if err != nil {
 			t.Fatal(err)

ethclient/simulated/backend_test.go

@@ -83,11 +83,7 @@ func newBlobTx(sim *Backend, key *ecdsa.PrivateKey) (*types.Transaction, error)
 		To:         addr,
 		AccessList: nil,
 		BlobHashes: []common.Hash{testBlobVHash},
-		Sidecar: &types.BlobTxSidecar{
-			Blobs:       []kzg4844.Blob{*testBlob},
-			Commitments: []kzg4844.Commitment{testBlobCommit},
-			Proofs:      []kzg4844.Proof{testBlobProof},
-		},
+		Sidecar:    types.NewBlobTxSidecar(types.BlobSidecarVersion0, []kzg4844.Blob{*testBlob}, []kzg4844.Commitment{testBlobCommit}, []kzg4844.Proof{testBlobProof}),
 	})
 	return types.SignTx(tx, types.LatestSignerForChainID(chainid), key)
 }

internal/ethapi/api.go

@@ -1603,11 +1603,7 @@ func (api *TransactionAPI) SignTransaction(ctx context.Context, args Transaction
 	// no longer retains the blobs, only the blob hashes. In this step, we need
 	// to put back the blob(s).
 	if args.IsEIP4844() {
-		signed = signed.WithBlobTxSidecar(&types.BlobTxSidecar{
-			Blobs:       args.Blobs,
-			Commitments: args.Commitments,
-			Proofs:      args.Proofs,
-		})
+		signed = signed.WithBlobTxSidecar(types.NewBlobTxSidecar(types.BlobSidecarVersion0, args.Blobs, args.Commitments, args.Proofs))
 	}
 	data, err := signed.MarshalBinary()
 	if err != nil {

internal/ethapi/api_test.go

@@ -2758,12 +2758,8 @@ func TestFillBlobTransaction(t *testing.T) {
 				Proofs:      []kzg4844.Proof{emptyBlobProof},
 			},
 			want: &result{
-				Hashes: []common.Hash{emptyBlobHash},
-				Sidecar: &types.BlobTxSidecar{
-					Blobs:       emptyBlobs,
-					Commitments: []kzg4844.Commitment{emptyBlobCommit},
-					Proofs:      []kzg4844.Proof{emptyBlobProof},
-				},
+				Hashes:  []common.Hash{emptyBlobHash},
+				Sidecar: types.NewBlobTxSidecar(types.BlobSidecarVersion0, emptyBlobs, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof}),
 			},
 		},
 		{
@@ -2778,12 +2774,8 @@ func TestFillBlobTransaction(t *testing.T) {
 				Proofs:      []kzg4844.Proof{emptyBlobProof},
 			},
 			want: &result{
-				Hashes: []common.Hash{emptyBlobHash},
-				Sidecar: &types.BlobTxSidecar{
-					Blobs:       emptyBlobs,
-					Commitments: []kzg4844.Commitment{emptyBlobCommit},
-					Proofs:      []kzg4844.Proof{emptyBlobProof},
-				},
+				Hashes:  []common.Hash{emptyBlobHash},
+				Sidecar: types.NewBlobTxSidecar(types.BlobSidecarVersion0, emptyBlobs, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof}),
 			},
 		},
 		{
@@ -2808,12 +2800,8 @@ func TestFillBlobTransaction(t *testing.T) {
 				Blobs: emptyBlobs,
 			},
 			want: &result{
-				Hashes: []common.Hash{emptyBlobHash},
-				Sidecar: &types.BlobTxSidecar{
-					Blobs:       emptyBlobs,
-					Commitments: []kzg4844.Commitment{emptyBlobCommit},
-					Proofs:      []kzg4844.Proof{emptyBlobProof},
-				},
+				Hashes:  []common.Hash{emptyBlobHash},
+				Sidecar: types.NewBlobTxSidecar(types.BlobSidecarVersion0, emptyBlobs, []kzg4844.Commitment{emptyBlobCommit}, []kzg4844.Proof{emptyBlobProof}),
 			},
 		},
 	}

internal/ethapi/transaction_args.go

@@ -527,11 +527,8 @@ func (args *TransactionArgs) ToTransaction(defaultType int) *types.Transaction {
 			BlobFeeCap: uint256.MustFromBig((*big.Int)(args.BlobFeeCap)),
 		}
 		if args.Blobs != nil {
-			data.(*types.BlobTx).Sidecar = &types.BlobTxSidecar{
-				Blobs:       args.Blobs,
-				Commitments: args.Commitments,
-				Proofs:      args.Proofs,
-			}
+			// TODO(rjl493456442, marius) support V1
+			data.(*types.BlobTx).Sidecar = types.NewBlobTxSidecar(types.BlobSidecarVersion0, args.Blobs, args.Commitments, args.Proofs)
 		}
 
 	case types.DynamicFeeTxType:

miner/worker.go

@@ -32,7 +32,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/txpool"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
-	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/holiman/uint256"
@@ -430,17 +429,13 @@ func (miner *Miner) commitTransactions(env *environment, plainTxs, blobTxs *tran
 		// Make sure all transactions after osaka have cell proofs
 		if isOsaka {
 			if sidecar := tx.BlobTxSidecar(); sidecar != nil {
-				if sidecar.Version == 0 {
+				if sidecar.Version == types.BlobSidecarVersion0 {
 					log.Info("Including blob tx with v0 sidecar, recomputing proofs", "hash", ltx.Hash)
-					sidecar.Proofs = make([]kzg4844.Proof, 0, len(sidecar.Blobs)*kzg4844.CellProofsPerBlob)
-					for _, blob := range sidecar.Blobs {
-						cellProofs, err := kzg4844.ComputeCellProofs(&blob)
-						if err != nil {
-							panic(err)
-						}
-						sidecar.Proofs = append(sidecar.Proofs, cellProofs...)
+					if err := sidecar.ToV1(); err != nil {
+						txs.Pop()
+						log.Warn("Failed to recompute cell proofs", "hash", ltx.Hash, "err", err)
+						continue
 					}
-					sidecar.Version = 1
 				}
 			}
 		}

signer/core/apitypes/types.go

@@ -167,11 +167,8 @@ func (args *SendTxArgs) ToTransaction() (*types.Transaction, error) {
 			BlobFeeCap: uint256.MustFromBig((*big.Int)(args.BlobFeeCap)),
 		}
 		if args.Blobs != nil {
-			data.(*types.BlobTx).Sidecar = &types.BlobTxSidecar{
-				Blobs:       args.Blobs,
-				Commitments: args.Commitments,
-				Proofs:      args.Proofs,
-			}
+			// TODO(rjl493456442, marius) support V1
+			data.(*types.BlobTx).Sidecar = types.NewBlobTxSidecar(types.BlobSidecarVersion0, args.Blobs, args.Commitments, args.Proofs)
 		}
 
 	case args.MaxFeePerGas != nil:
@@ -222,7 +219,6 @@ func (args *SendTxArgs) validateTxSidecar() error {
 		return nil
 	}
 
-	n := len(args.Blobs)
 	// Assume user provides either only blobs (w/o hashes), or
 	// blobs together with commitments and proofs.
 	if args.Commitments == nil && args.Proofs != nil {
@@ -232,6 +228,7 @@ func (args *SendTxArgs) validateTxSidecar() error {
 	}
 
 	// len(blobs) == len(commitments) == len(proofs) == len(hashes)
+	n := len(args.Blobs)
 	if args.Commitments != nil && len(args.Commitments) != n {
 		return fmt.Errorf("number of blobs and commitments mismatch (have=%d, want=%d)", len(args.Commitments), n)
 	}

signer/core/apitypes/types_test.go

@@ -129,11 +129,7 @@ func TestBlobTxs(t *testing.T) {
 		BlobFeeCap: uint256.NewInt(700),
 		BlobHashes: []common.Hash{hash},
 		Value:      uint256.NewInt(100),
-		Sidecar: &types.BlobTxSidecar{
-			Blobs:       []kzg4844.Blob{blob},
-			Commitments: []kzg4844.Commitment{commitment},
-			Proofs:      []kzg4844.Proof{proof},
-		},
+		Sidecar:    types.NewBlobTxSidecar(types.BlobSidecarVersion0, []kzg4844.Blob{blob}, []kzg4844.Commitment{commitment}, []kzg4844.Proof{proof}),
 	}
 	tx := types.NewTx(b)
 	data, err := json.Marshal(tx)