core/vm: adds refund as part of the json standard trace (#17910)

This adds the global accumulated refund counter to the standard
json output as a numeric json value. Previously this was not very
interesting since it was not used much, but with the new sstore
gas changes the value is a lot more interesting from a consensus
investigation perspective.

cmd/evm/json_logger.go

@@ -52,6 +52,7 @@ func (l *JSONLogger) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cos
 		MemorySize:    memory.Len(),
 		Storage:       nil,
 		Depth:         depth,
+		RefundCounter: env.StateDB.GetRefund(),
 		Err:           err,
 	}
 	if !l.cfg.DisableMemory {

core/vm/gen_structlog.go

@@ -13,6 +13,7 @@ import (
 
 var _ = (*structLogMarshaling)(nil)
 
+// MarshalJSON marshals as JSON.
 func (s StructLog) MarshalJSON() ([]byte, error) {
 	type StructLog struct {
 		Pc            uint64                      `json:"pc"`
@@ -24,6 +25,7 @@ func (s StructLog) MarshalJSON() ([]byte, error) {
 		Stack         []*math.HexOrDecimal256     `json:"stack"`
 		Storage       map[common.Hash]common.Hash `json:"-"`
 		Depth         int                         `json:"depth"`
+		RefundCounter uint64                      `json:"refund"`
 		Err           error                       `json:"-"`
 		OpName        string                      `json:"opName"`
 		ErrorString   string                      `json:"error"`
@@ -43,12 +45,14 @@ func (s StructLog) MarshalJSON() ([]byte, error) {
 	}
 	enc.Storage = s.Storage
 	enc.Depth = s.Depth
+	enc.RefundCounter = s.RefundCounter
 	enc.Err = s.Err
 	enc.OpName = s.OpName()
 	enc.ErrorString = s.ErrorString()
 	return json.Marshal(&enc)
 }
 
+// UnmarshalJSON unmarshals from JSON.
 func (s *StructLog) UnmarshalJSON(input []byte) error {
 	type StructLog struct {
 		Pc            *uint64                     `json:"pc"`
@@ -60,6 +64,7 @@ func (s *StructLog) UnmarshalJSON(input []byte) error {
 		Stack         []*math.HexOrDecimal256     `json:"stack"`
 		Storage       map[common.Hash]common.Hash `json:"-"`
 		Depth         *int                        `json:"depth"`
+		RefundCounter *uint64                     `json:"refund"`
 		Err           error                       `json:"-"`
 	}
 	var dec StructLog
@@ -96,6 +101,9 @@ func (s *StructLog) UnmarshalJSON(input []byte) error {
 	if dec.Depth != nil {
 		s.Depth = *dec.Depth
 	}
+	if dec.RefundCounter != nil {
+		s.RefundCounter = *dec.RefundCounter
+	}
 	if dec.Err != nil {
 		s.Err = dec.Err
 	}

core/vm/logger.go

@@ -65,6 +65,7 @@ type StructLog struct {
 	Stack         []*big.Int                  `json:"stack"`
 	Storage       map[common.Hash]common.Hash `json:"-"`
 	Depth         int                         `json:"depth"`
+	RefundCounter uint64                      `json:"refund"`
 	Err           error                       `json:"-"`
 }
 
@@ -177,7 +178,7 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 		storage = l.changedValues[contract.Address()].Copy()
 	}
 	// create a new snaptshot of the EVM.
-	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, storage, depth, err}
+	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, storage, depth, env.StateDB.GetRefund(), err}
 
 	l.logs = append(l.logs, log)
 	return nil

core/vm/logger_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -41,9 +42,15 @@ func (d *dummyContractRef) SetBalance(*big.Int)        {}
 func (d *dummyContractRef) SetNonce(uint64)            {}
 func (d *dummyContractRef) Balance() *big.Int          { return new(big.Int) }
 
+type dummyStatedb struct {
+	state.StateDB
+}
+
+func (dummyStatedb) GetRefund() uint64 { return 1337 }
+
 func TestStoreCapture(t *testing.T) {
 	var (
-		env      = NewEVM(Context{}, nil, params.TestChainConfig, Config{})
+		env      = NewEVM(Context{}, &dummyStatedb{}, params.TestChainConfig, Config{})
 		logger   = NewStructLogger(nil)
 		mem      = NewMemory()
 		stack    = newstack()
@@ -51,9 +58,7 @@ func TestStoreCapture(t *testing.T) {
 	)
 	stack.push(big.NewInt(1))
 	stack.push(big.NewInt(0))
-
 	var index common.Hash
-
 	logger.CaptureState(env, 0, SSTORE, 0, 0, mem, stack, contract, 0, nil)
 	if len(logger.changedValues[contract.Address()]) == 0 {
 		t.Fatalf("expected exactly 1 changed value on address %x, got %d", contract.Address(), len(logger.changedValues[contract.Address()]))

eth/tracers/tracer.go

@@ -295,6 +295,7 @@ type Tracer struct {
 	costValue   *uint   // Swappable cost value wrapped by a log accessor
 	depthValue  *uint   // Swappable depth value wrapped by a log accessor
 	errorValue  *string // Swappable error value wrapped by a log accessor
+	refundValue *uint   // Swappable refund value wrapped by a log accessor
 
 	ctx map[string]interface{} // Transaction context gathered throughout execution
 	err error                  // Error, if one has occurred
@@ -323,6 +324,7 @@ func New(code string) (*Tracer, error) {
 		gasValue:        new(uint),
 		costValue:       new(uint),
 		depthValue:      new(uint),
+		refundValue:     new(uint),
 	}
 	// Set up builtins for this environment
 	tracer.vm.PushGlobalGoFunction("toHex", func(ctx *duktape.Context) int {
@@ -442,6 +444,9 @@ func New(code string) (*Tracer, error) {
 	tracer.vm.PushGoFunction(func(ctx *duktape.Context) int { ctx.PushUint(*tracer.depthValue); return 1 })
 	tracer.vm.PutPropString(logObject, "getDepth")
 
+	tracer.vm.PushGoFunction(func(ctx *duktape.Context) int { ctx.PushUint(*tracer.refundValue); return 1 })
+	tracer.vm.PutPropString(logObject, "getRefund")
+
 	tracer.vm.PushGoFunction(func(ctx *duktape.Context) int {
 		if tracer.errorValue != nil {
 			ctx.PushString(*tracer.errorValue)
@@ -527,6 +532,7 @@ func (jst *Tracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost
 		*jst.gasValue = uint(gas)
 		*jst.costValue = uint(cost)
 		*jst.depthValue = uint(depth)
+		*jst.refundValue = uint(env.StateDB.GetRefund())
 
 		jst.errorValue = nil
 		if err != nil {

eth/tracers/tracer_test.go

@@ -25,6 +25,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/params"
 )
@@ -43,8 +44,14 @@ func (account) ReturnGas(*big.Int)                                  {}
 func (account) SetCode(common.Hash, []byte)                         {}
 func (account) ForEachStorage(cb func(key, value common.Hash) bool) {}
 
+type dummyStatedb struct {
+	state.StateDB
+}
+
+func (dummyStatedb) GetRefund() uint64 { return 1337 }
+
 func runTrace(tracer *Tracer) (json.RawMessage, error) {
-	env := vm.NewEVM(vm.Context{BlockNumber: big.NewInt(1)}, nil, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
+	env := vm.NewEVM(vm.Context{BlockNumber: big.NewInt(1)}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
 
 	contract := vm.NewContract(account{}, account{}, big.NewInt(0), 10000)
 	contract.Code = []byte{byte(vm.PUSH1), 0x1, byte(vm.PUSH1), 0x1, 0x0}
@@ -126,7 +133,7 @@ func TestHaltBetweenSteps(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	env := vm.NewEVM(vm.Context{BlockNumber: big.NewInt(1)}, nil, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
+	env := vm.NewEVM(vm.Context{BlockNumber: big.NewInt(1)}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
 	contract := vm.NewContract(&account{}, &account{}, big.NewInt(0), 0)
 
 	tracer.CaptureState(env, 0, 0, 0, 0, nil, nil, contract, 0, nil)