go-ethereum/eth/tracers/logger/logger_test.go

// Copyright 2021 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package logger

import (
	"encoding/json"
	"errors"
	"math/big"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/state"
	"github.com/ethereum/go-ethereum/core/tracing"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/params"
	"github.com/holiman/uint256"
)

type dummyStatedb struct {
	state.StateDB
}

func (*dummyStatedb) GetRefund() uint64                                    { return 1337 }
func (*dummyStatedb) GetState(_ common.Address, _ common.Hash) common.Hash { return common.Hash{} }
func (*dummyStatedb) SetState(_ common.Address, _ common.Hash, _ common.Hash) common.Hash {
	return common.Hash{}
}

func (*dummyStatedb) GetStateAndCommittedState(common.Address, common.Hash) (common.Hash, common.Hash) {
	return common.Hash{}, common.Hash{}
}

type dummyOpContext struct{}

func (dummyOpContext) MemoryData() []byte       { return nil }
func (dummyOpContext) StackData() []uint256.Int { return nil }
func (dummyOpContext) Caller() common.Address   { return common.Address{} }
func (dummyOpContext) Address() common.Address  { return common.Address{} }
func (dummyOpContext) CallValue() *uint256.Int  { return new(uint256.Int) }
func (dummyOpContext) CallInput() []byte        { return nil }
func (dummyOpContext) ContractCode() []byte     { return nil }

func TestStoreCapture(t *testing.T) {
	var (
		logger   = NewStructLogger(nil)
		evm      = vm.NewEVM(vm.BlockContext{}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Tracer: logger.Hooks()})
		contract = vm.NewContract(common.Address{}, common.Address{}, new(uint256.Int), 100000, nil)
	)
	contract.Code = []byte{byte(vm.PUSH1), 0x1, byte(vm.PUSH1), 0x0, byte(vm.SSTORE)}
	var index common.Hash
	logger.OnTxStart(evm.GetVMContext(), nil, common.Address{})
	_, err := evm.Run(contract, []byte{}, false)
	if err != nil {
		t.Fatal(err)
	}
	if len(logger.storage[contract.Address()]) == 0 {
		t.Fatalf("expected exactly 1 changed value on address %x, got %d", contract.Address(),
			len(logger.storage[contract.Address()]))
	}
	exp := common.BigToHash(big.NewInt(1))
	if logger.storage[contract.Address()][index] != exp {
		t.Errorf("expected %x, got %x", exp, logger.storage[contract.Address()][index])
	}
}

// Tests that blank fields don't appear in logs when JSON marshalled, to reduce
// logs bloat and confusion. See https://github.com/ethereum/go-ethereum/issues/24487
func TestStructLogMarshalingOmitEmpty(t *testing.T) {
	tests := []struct {
		name string
		log  *StructLog
		want string
	}{
		{"empty err and no fields", &StructLog{},
			`{"pc":0,"op":0,"gas":"0x0","gasCost":"0x0","memSize":0,"stack":null,"depth":0,"refund":0,"opName":"STOP"}`},
		{"with err", &StructLog{Err: errors.New("this failed")},
			`{"pc":0,"op":0,"gas":"0x0","gasCost":"0x0","memSize":0,"stack":null,"depth":0,"refund":0,"opName":"STOP","error":"this failed"}`},
		{"with mem", &StructLog{Memory: make([]byte, 2), MemorySize: 2},
			`{"pc":0,"op":0,"gas":"0x0","gasCost":"0x0","memory":"0x0000","memSize":2,"stack":null,"depth":0,"refund":0,"opName":"STOP"}`},
		{"with 0-size mem", &StructLog{Memory: make([]byte, 0)},
			`{"pc":0,"op":0,"gas":"0x0","gasCost":"0x0","memSize":0,"stack":null,"depth":0,"refund":0,"opName":"STOP"}`},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			blob, err := json.Marshal(tt.log)
			if err != nil {
				t.Fatal(err)
			}
			if have, want := string(blob), tt.want; have != want {
				t.Fatalf("mismatched results\n\thave: %v\n\twant: %v", have, want)
			}
		})
	}
}

func TestStructLogLegacyJSONSpecFormatting(t *testing.T) {
	tests := []struct {
		name string
		log  *StructLog
		want string
	}{
		{
			name: "omits empty error and pads memory/storage",
			log: &StructLog{
				Pc:         7,
				Op:         vm.SSTORE,
				Gas:        100,
				GasCost:    20,
				Memory:     []byte{0xaa, 0xbb},
				Storage:    map[common.Hash]common.Hash{common.BigToHash(big.NewInt(1)): common.BigToHash(big.NewInt(2))},
				Depth:      1,
				ReturnData: []byte{0x12, 0x34},
			},
			want: `{"pc":7,"op":"SSTORE","gas":100,"gasCost":20,"depth":1,"returnData":"0x1234","memory":["0xaabb000000000000000000000000000000000000000000000000000000000000"],"storage":{"0x0000000000000000000000000000000000000000000000000000000000000001":"0x0000000000000000000000000000000000000000000000000000000000000002"}}`,
		},
		{
			name: "includes error only when present",
			log: &StructLog{
				Pc:      1,
				Op:      vm.STOP,
				Gas:     2,
				GasCost: 3,
				Depth:   1,
				Err:     errors.New("boom"),
			},
			want: `{"pc":1,"op":"STOP","gas":2,"gasCost":3,"depth":1,"error":"boom"}`,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			have := string(tt.log.toLegacyJSON())
			if have != tt.want {
				t.Fatalf("mismatched results\n\thave: %v\n\twant: %v", have, tt.want)
			}
		})
	}
}

func TestStructLoggerLimitRejectsOversizedEntry(t *testing.T) {
	entry := (&StructLog{Op: vm.STOP, RefundCounter: 1337}).toLegacyJSON()
	logger := NewStructLogger(&Config{Limit: len(entry) - 1})
	logger.env = &tracing.VMContext{StateDB: &dummyStatedb{}}

	logger.OnOpcode(0, byte(vm.STOP), 0, 0, dummyOpContext{}, nil, 0, nil)

	if len(logger.logs) != 0 {
		t.Fatalf("expected oversized entry to be skipped, got %d logs", len(logger.logs))
	}
	if logger.resultSize != 0 {
		t.Fatalf("expected result size to remain zero, got %d", logger.resultSize)
	}
}

func TestStructLoggerLimitAllowsEntryUpToBoundary(t *testing.T) {
	entry := (&StructLog{Op: vm.STOP, RefundCounter: 1337}).toLegacyJSON()
	logger := NewStructLogger(&Config{Limit: len(entry)})
	logger.env = &tracing.VMContext{StateDB: &dummyStatedb{}}

	logger.OnOpcode(0, byte(vm.STOP), 0, 0, dummyOpContext{}, nil, 0, nil)
	logger.OnOpcode(0, byte(vm.STOP), 0, 0, dummyOpContext{}, nil, 0, nil)

	if len(logger.logs) != 1 {
		t.Fatalf("expected exactly one log at the size boundary, got %d", len(logger.logs))
	}
	if logger.resultSize != len(entry) {
		t.Fatalf("expected result size %d, got %d", len(entry), logger.resultSize)
	}
}