TransactionByHash returns error

[envestcc]

What version of iotex-core image (or code branch) are you using?

v1.11.1

What operating system and processor architecture are you using?

macOS, M1 Pro

What did you do? If possible, provide a recipe for reproducing the error.

querying transaction via ethclient on testnet for tx hash 0xcbc2560d986d79a46bfd96a08d18c6045b29f97352c1360289e371d9cffd6b6a returns error:

package main

import (
	"context"
	"math/big"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/stretchr/testify/require"
)

func TestIoTexRead(t *testing.T) {
	r := require.New(t)

	cli, err := ethclient.Dial("https://babel-api.testnet.iotex.io")
	r.NoError(err)
	tx, isPending, err := cli.TransactionByHash(context.Background(), common.HexToHash("0xcbc2560d986d79a46bfd96a08d18c6045b29f97352c1360289e371d9cffd6b6a"))
	r.NoError(err)
	r.False(isPending)
	r.NotNil(tx)
	t.Logf("%+v", tx)
}

What did you expect to see?

should return transaction information

What did you see instead?

❯ go test -v -timeout 45s -run ^TestIoTexRead$ testgo/eth
=== RUN   TestIoTexRead
    base_test.go:36: 
                Error Trace:    /Users/chenchen/dev/testgo/eth/base_test.go:36
                Error:          Received unexpected error:
                                json: cannot unmarshal hex number with leading zero digits into Go struct field txJSON.r of type *hexutil.Big
                Test:           TestIoTexRead
--- FAIL: TestIoTexRead (0.90s)
FAIL
FAIL    testgo/eth      1.045s
FAIL

[envestcc]

The output of eth_getTransactionByHash for this tx is as follows:

{
    "hash": "0xcbc2560d986d79a46bfd96a08d18c6045b29f97352c1360289e371d9cffd6b6a",
    "nonce": "0x131",
    "blockHash": "0xbdcf722cbc0dc9b9eb5b46ad4af9e15944a886310b1cb2227129070c0e4b7de5",
    "blockNumber": "0x1551bdb",
    "transactionIndex": "0x0",
    "from": "0xec4daee51c4bf81bd00af165f8ca66823ee3b12a",
    "to": "0xc3527348De07d591c9d567ce1998eFA2031B8675",
    "value": "0x0",
    "gasPrice": "0xe8d4a51000",
    "gas": "0x488ab",
    "input": "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",
    "r": "0x00d50c3169003e7c9c9392069a1c9e5251c8f558120cceb9aa312f0fa4624770",
    "s": "0x1f4cad47a5540cdda5459f7a46c62df752ca588e0b73722ec767ff08994134a4",
    "v": "0x1b"
}

According to the error message, the reason should be that the format of the r field is invalid, which can not begin with 0.

[envestcc]

Compare the implementation:
iotex

// api/web3server_marshal.go:263
R:                byteToHex(obj.signature[:32]),

// api/web3server_utils.go:247
func byteToHex(b []byte) string {
	return "0x" + hex.EncodeToString(b)
}

eth

// internal/ethapi/api.go:1446
v, r, s := tx.RawSignatureValues()
...
R:        (*hexutil.Big)(r),

// common/hexutil/hexutil.go:179
func EncodeBig(bigint *big.Int) string {
	if sign := bigint.Sign(); sign == 0 {
		return "0x0"
	} else if sign > 0 {
		return "0x" + bigint.Text(16)
	} else {
		return "-0x" + bigint.Text(16)[1:]
	}
}

// core/types/transaction_signing.go:536
func decodeSignature(sig []byte) (r, s, v *big.Int) {
	if len(sig) != crypto.SignatureLength {
		panic(fmt.Sprintf("wrong size for signature: got %d, want %d", len(sig), crypto.SignatureLength))
	}
	r = new(big.Int).SetBytes(sig[:32])
	s = new(big.Int).SetBytes(sig[32:64])
	v = new(big.Int).SetBytes([]byte{sig[64] + 27})
	return r, s, v
}