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all: seperate consensus error and evm internal error (#20830)
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* all: seperate consensus error and evm internal error

There are actually two types of error will be returned when
a tranaction/message call is executed: (a) consensus error
(b) evm internal error. The former should be converted to
a consensus issue, e.g. The sender doesn't enough asset to
purchase the gas it specifies. The latter is allowed since
evm itself is a blackbox and internal error is allowed to happen.

This PR emphasizes the difference by introducing a executionResult
structure. The evm error is embedded inside. So if any error
returned, it indicates consensus issue happens.

And also this PR improve the `EstimateGas` API to return the concrete
revert reason if the transaction always fails

* all: polish

* accounts/abi/bind/backends: add tests

* accounts/abi/bind/backends, internal: cleanup error message

* all: address comments

* core: fix lint

* accounts, core, eth, internal: address comments

* accounts, internal: resolve revert reason if possible

* accounts, internal: address comments
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@rjl493456442
rjl493456442 authored Apr 22, 2020
1 parent c60c0c9 commit b9df7ec
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Showing 33 changed files with 550 additions and 238 deletions.
23 changes: 23 additions & 0 deletions accounts/abi/abi.go
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ import (
"io"

"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
)

// The ABI holds information about a contract's context and available
Expand Down Expand Up @@ -234,3 +235,25 @@ func (abi *ABI) HasFallback() bool {
func (abi *ABI) HasReceive() bool {
return abi.Receive.Type == Receive
}

// revertSelector is a special function selector for revert reason unpacking.
var revertSelector = crypto.Keccak256([]byte("Error(string)"))[:4]

// UnpackRevert resolves the abi-encoded revert reason. According to the solidity
// spec https://solidity.readthedocs.io/en/latest/control-structures.html#revert,
// the provided revert reason is abi-encoded as if it were a call to a function
// `Error(string)`. So it's a special tool for it.
func UnpackRevert(data []byte) (string, error) {
if len(data) < 4 {
return "", errors.New("invalid data for unpacking")
}
if !bytes.Equal(data[:4], revertSelector) {
return "", errors.New("invalid data for unpacking")
}
var reason string
typ, _ := NewType("string", "", nil)
if err := (Arguments{{Type: typ}}).Unpack(&reason, data[4:]); err != nil {
return "", err
}
return reason, nil
}
32 changes: 32 additions & 0 deletions accounts/abi/abi_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ package abi
import (
"bytes"
"encoding/hex"
"errors"
"fmt"
"math/big"
"reflect"
Expand Down Expand Up @@ -1070,3 +1071,34 @@ func TestUnnamedEventParam(t *testing.T) {
t.Fatalf("Could not find input")
}
}

func TestUnpackRevert(t *testing.T) {
t.Parallel()

var cases = []struct {
input string
expect string
expectErr error
}{
{"", "", errors.New("invalid data for unpacking")},
{"08c379a1", "", errors.New("invalid data for unpacking")},
{"08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000d72657665727420726561736f6e00000000000000000000000000000000000000", "revert reason", nil},
}
for index, c := range cases {
t.Run(fmt.Sprintf("case %d", index), func(t *testing.T) {
got, err := UnpackRevert(common.Hex2Bytes(c.input))
if c.expectErr != nil {
if err == nil {
t.Fatalf("Expected non-nil error")
}
if err.Error() != c.expectErr.Error() {
t.Fatalf("Expected error mismatch, want %v, got %v", c.expectErr, err)
}
return
}
if c.expect != got {
t.Fatalf("Output mismatch, want %v, got %v", c.expect, got)
}
})
}
}
62 changes: 48 additions & 14 deletions accounts/abi/bind/backends/simulated.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ import (
"time"

"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/accounts/abi"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
Expand All @@ -49,7 +50,6 @@ var (
errBlockNumberUnsupported = errors.New("simulatedBackend cannot access blocks other than the latest block")
errBlockDoesNotExist = errors.New("block does not exist in blockchain")
errTransactionDoesNotExist = errors.New("transaction does not exist")
errGasEstimationFailed = errors.New("gas required exceeds allowance or always failing transaction")
)

// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
Expand Down Expand Up @@ -349,8 +349,11 @@ func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallM
if err != nil {
return nil, err
}
rval, _, _, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), state)
return rval, err
res, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), state)
if err != nil {
return nil, err
}
return res.Return(), nil
}

// PendingCallContract executes a contract call on the pending state.
Expand All @@ -359,8 +362,11 @@ func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereu
defer b.mu.Unlock()
defer b.pendingState.RevertToSnapshot(b.pendingState.Snapshot())

rval, _, _, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
return rval, err
res, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
if err != nil {
return nil, err
}
return res.Return(), nil
}

// PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
Expand Down Expand Up @@ -398,39 +404,67 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
cap = hi

// Create a helper to check if a gas allowance results in an executable transaction
executable := func(gas uint64) bool {
executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
call.Gas = gas

snapshot := b.pendingState.Snapshot()
_, _, failed, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
res, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
b.pendingState.RevertToSnapshot(snapshot)

if err != nil || failed {
return false
if err != nil {
if err == core.ErrIntrinsicGas {
return true, nil, nil // Special case, raise gas limit
}
return true, nil, err // Bail out
}
return true
return res.Failed(), res, nil
}
// Execute the binary search and hone in on an executable gas limit
for lo+1 < hi {
mid := (hi + lo) / 2
if !executable(mid) {
failed, _, err := executable(mid)

// If the error is not nil(consensus error), it means the provided message
// call or transaction will never be accepted no matter how much gas it is
// assigned. Return the error directly, don't struggle any more
if err != nil {
return 0, err
}
if failed {
lo = mid
} else {
hi = mid
}
}
// Reject the transaction as invalid if it still fails at the highest allowance
if hi == cap {
if !executable(hi) {
return 0, errGasEstimationFailed
failed, result, err := executable(hi)
if err != nil {
return 0, err
}
if failed {
if result != nil && result.Err != vm.ErrOutOfGas {
errMsg := fmt.Sprintf("always failing transaction (%v)", result.Err)
if len(result.Revert()) > 0 {
ret, err := abi.UnpackRevert(result.Revert())
if err != nil {
errMsg += fmt.Sprintf(" (%#x)", result.Revert())
} else {
errMsg += fmt.Sprintf(" (%s)", ret)
}
}
return 0, errors.New(errMsg)
}
// Otherwise, the specified gas cap is too low
return 0, fmt.Errorf("gas required exceeds allowance (%d)", cap)
}
}
return hi, nil
}

// callContract implements common code between normal and pending contract calls.
// state is modified during execution, make sure to copy it if necessary.
func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) ([]byte, uint64, bool, error) {
func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) (*core.ExecutionResult, error) {
// Ensure message is initialized properly.
if call.GasPrice == nil {
call.GasPrice = big.NewInt(1)
Expand Down
120 changes: 104 additions & 16 deletions accounts/abi/bind/backends/simulated_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ package backends
import (
"bytes"
"context"
"errors"
"math/big"
"strings"
"testing"
Expand Down Expand Up @@ -356,25 +357,112 @@ func TestSimulatedBackend_TransactionByHash(t *testing.T) {
}

func TestSimulatedBackend_EstimateGas(t *testing.T) {
sim := NewSimulatedBackend(
core.GenesisAlloc{}, 10000000,
)
/*
pragma solidity ^0.6.4;
contract GasEstimation {
function PureRevert() public { revert(); }
function Revert() public { revert("revert reason");}
function OOG() public { for (uint i = 0; ; i++) {}}
function Assert() public { assert(false);}
function Valid() public {}
}*/
const contractAbi = "[{\"inputs\":[],\"name\":\"Assert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"OOG\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"PureRevert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Revert\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"Valid\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]"
const contractBin = "0x60806040523480156100115760006000fd5b50610017565b61016e806100266000396000f3fe60806040523480156100115760006000fd5b506004361061005c5760003560e01c806350f6fe3414610062578063aa8b1d301461006c578063b9b046f914610076578063d8b9839114610080578063e09fface1461008a5761005c565b60006000fd5b61006a610094565b005b6100746100ad565b005b61007e6100b5565b005b6100886100c2565b005b610092610135565b005b6000600090505b5b808060010191505061009b565b505b565b60006000fd5b565b600015156100bf57fe5b5b565b6040517f08c379a000000000000000000000000000000000000000000000000000000000815260040180806020018281038252600d8152602001807f72657665727420726561736f6e0000000000000000000000000000000000000081526020015060200191505060405180910390fd5b565b5b56fea2646970667358221220345bbcbb1a5ecf22b53a78eaebf95f8ee0eceff6d10d4b9643495084d2ec934a64736f6c63430006040033"

key, _ := crypto.GenerateKey()
addr := crypto.PubkeyToAddress(key.PublicKey)
opts := bind.NewKeyedTransactor(key)

sim := NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(params.Ether)}}, 10000000)
defer sim.Close()
bgCtx := context.Background()
testAddr := crypto.PubkeyToAddress(testKey.PublicKey)

gas, err := sim.EstimateGas(bgCtx, ethereum.CallMsg{
From: testAddr,
To: &testAddr,
Value: big.NewInt(1000),
Data: []byte{},
})
if err != nil {
t.Errorf("could not estimate gas: %v", err)
}
parsed, _ := abi.JSON(strings.NewReader(contractAbi))
contractAddr, _, _, _ := bind.DeployContract(opts, parsed, common.FromHex(contractBin), sim)
sim.Commit()

if gas != params.TxGas {
t.Errorf("expected 21000 gas cost for a transaction got %v", gas)
var cases = []struct {
name string
message ethereum.CallMsg
expect uint64
expectError error
}{
{"plain transfer(valid)", ethereum.CallMsg{
From: addr,
To: &addr,
Gas: 0,
GasPrice: big.NewInt(0),
Value: big.NewInt(1),
Data: nil,
}, params.TxGas, nil},

{"plain transfer(invalid)", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 0,
GasPrice: big.NewInt(0),
Value: big.NewInt(1),
Data: nil,
}, 0, errors.New("always failing transaction (execution reverted)")},

{"Revert", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 0,
GasPrice: big.NewInt(0),
Value: nil,
Data: common.Hex2Bytes("d8b98391"),
}, 0, errors.New("always failing transaction (execution reverted) (revert reason)")},

{"PureRevert", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 0,
GasPrice: big.NewInt(0),
Value: nil,
Data: common.Hex2Bytes("aa8b1d30"),
}, 0, errors.New("always failing transaction (execution reverted)")},

{"OOG", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 100000,
GasPrice: big.NewInt(0),
Value: nil,
Data: common.Hex2Bytes("50f6fe34"),
}, 0, errors.New("gas required exceeds allowance (100000)")},

{"Assert", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 100000,
GasPrice: big.NewInt(0),
Value: nil,
Data: common.Hex2Bytes("b9b046f9"),
}, 0, errors.New("always failing transaction (invalid opcode: opcode 0xfe not defined)")},

{"Valid", ethereum.CallMsg{
From: addr,
To: &contractAddr,
Gas: 100000,
GasPrice: big.NewInt(0),
Value: nil,
Data: common.Hex2Bytes("e09fface"),
}, 21275, nil},
}
for _, c := range cases {
got, err := sim.EstimateGas(context.Background(), c.message)
if c.expectError != nil {
if err == nil {
t.Fatalf("Expect error, got nil")
}
if c.expectError.Error() != err.Error() {
t.Fatalf("Expect error, want %v, got %v", c.expectError, err)
}
continue
}
if got != c.expect {
t.Fatalf("Gas estimation mismatch, want %d, got %d", c.expect, got)
}
}
}

Expand Down
4 changes: 2 additions & 2 deletions cmd/geth/retesteth.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -678,7 +678,7 @@ func (api *RetestethAPI) AccountRange(ctx context.Context,
context := core.NewEVMContext(msg, block.Header(), api.blockchain, nil)
// Not yet the searched for transaction, execute on top of the current state
vmenv := vm.NewEVM(context, statedb, api.blockchain.Config(), vm.Config{})
if _, _, _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil {
if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil {
return AccountRangeResult{}, fmt.Errorf("transaction %#x failed: %v", tx.Hash(), err)
}
// Ensure any modifications are committed to the state
Expand Down Expand Up @@ -788,7 +788,7 @@ func (api *RetestethAPI) StorageRangeAt(ctx context.Context,
context := core.NewEVMContext(msg, block.Header(), api.blockchain, nil)
// Not yet the searched for transaction, execute on top of the current state
vmenv := vm.NewEVM(context, statedb, api.blockchain.Config(), vm.Config{})
if _, _, _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil {
if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil {
return StorageRangeResult{}, fmt.Errorf("transaction %#x failed: %v", tx.Hash(), err)
}
// Ensure any modifications are committed to the state
Expand Down
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