eth/tracers: various fixes (#30540)

Breaking changes:

- The ChainConfig was exposed to tracers via VMContext passed in
`OnTxStart`. This is unnecessary specially looking through the lens of
live tracers as chain config remains the same throughout the lifetime of
the program. It was there so that native API-invoked tracers could
access it. So instead we moved it to the constructor of API tracers.

Non-breaking:

- Change the default config of the tracers to be `{}` instead of nil.
This way an extra nil check can be avoided.

Refactoring:

- Rename `supply` struct to `supplyTracer`.
- Un-export some hook definitions.

cmd/evm/internal/t8ntool/execution.go

@@ -132,7 +132,7 @@ type rejectedTx struct {
 // Apply applies a set of transactions to a pre-state
 func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 	txIt txIterator, miningReward int64,
-	getTracerFn func(txIndex int, txHash common.Hash) (*tracers.Tracer, io.WriteCloser, error)) (*state.StateDB, *ExecutionResult, []byte, error) {
+	getTracerFn func(txIndex int, txHash common.Hash, chainConfig *params.ChainConfig) (*tracers.Tracer, io.WriteCloser, error)) (*state.StateDB, *ExecutionResult, []byte, error) {
 	// Capture errors for BLOCKHASH operation, if we haven't been supplied the
 	// required blockhashes
 	var hashError error
@@ -242,7 +242,7 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 				continue
 			}
 		}
-		tracer, traceOutput, err := getTracerFn(txIndex, tx.Hash())
+		tracer, traceOutput, err := getTracerFn(txIndex, tx.Hash(), chainConfig)
 		if err != nil {
 			return nil, nil, nil, err
 		}

cmd/evm/internal/t8ntool/transition.go

@@ -82,7 +82,9 @@ type input struct {
 }
 
 func Transition(ctx *cli.Context) error {
-	var getTracer = func(txIndex int, txHash common.Hash) (*tracers.Tracer, io.WriteCloser, error) { return nil, nil, nil }
+	var getTracer = func(txIndex int, txHash common.Hash, chainConfig *params.ChainConfig) (*tracers.Tracer, io.WriteCloser, error) {
+		return nil, nil, nil
+	}
 
 	baseDir, err := createBasedir(ctx)
 	if err != nil {
@@ -97,7 +99,7 @@ func Transition(ctx *cli.Context) error {
 			EnableReturnData: ctx.Bool(TraceEnableReturnDataFlag.Name),
 			Debug:            true,
 		}
-		getTracer = func(txIndex int, txHash common.Hash) (*tracers.Tracer, io.WriteCloser, error) {
+		getTracer = func(txIndex int, txHash common.Hash, _ *params.ChainConfig) (*tracers.Tracer, io.WriteCloser, error) {
 			traceFile, err := os.Create(filepath.Join(baseDir, fmt.Sprintf("trace-%d-%v.jsonl", txIndex, txHash.String())))
 			if err != nil {
 				return nil, nil, NewError(ErrorIO, fmt.Errorf("failed creating trace-file: %v", err))
@@ -121,12 +123,12 @@ func Transition(ctx *cli.Context) error {
 		if ctx.IsSet(TraceTracerConfigFlag.Name) {
 			config = []byte(ctx.String(TraceTracerConfigFlag.Name))
 		}
-		getTracer = func(txIndex int, txHash common.Hash) (*tracers.Tracer, io.WriteCloser, error) {
+		getTracer = func(txIndex int, txHash common.Hash, chainConfig *params.ChainConfig) (*tracers.Tracer, io.WriteCloser, error) {
 			traceFile, err := os.Create(filepath.Join(baseDir, fmt.Sprintf("trace-%d-%v.json", txIndex, txHash.String())))
 			if err != nil {
 				return nil, nil, NewError(ErrorIO, fmt.Errorf("failed creating trace-file: %v", err))
 			}
-			tracer, err := tracers.DefaultDirectory.New(ctx.String(TraceTracerFlag.Name), nil, config)
+			tracer, err := tracers.DefaultDirectory.New(ctx.String(TraceTracerFlag.Name), nil, config, chainConfig)
 			if err != nil {
 				return nil, nil, NewError(ErrorConfig, fmt.Errorf("failed instantiating tracer: %w", err))
 			}

cmd/utils/flags.go

@@ -543,6 +543,7 @@ var (
 	VMTraceJsonConfigFlag = &cli.StringFlag{
 		Name:     "vmtrace.jsonconfig",
 		Usage:    "Tracer configuration (JSON)",
+		Value:    "{}",
 		Category: flags.VMCategory,
 	}
 	// API options.
@@ -1899,13 +1900,8 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	// VM tracing config.
 	if ctx.IsSet(VMTraceFlag.Name) {
 		if name := ctx.String(VMTraceFlag.Name); name != "" {
-			var config string
-			if ctx.IsSet(VMTraceJsonConfigFlag.Name) {
-				config = ctx.String(VMTraceJsonConfigFlag.Name)
-			}
-
 			cfg.VMTrace = name
-			cfg.VMTraceJsonConfig = config
+			cfg.VMTraceJsonConfig = ctx.String(VMTraceJsonConfigFlag.Name)
 		}
 	}
 }
@@ -2186,10 +2182,7 @@ func MakeChain(ctx *cli.Context, stack *node.Node, readonly bool) (*core.BlockCh
 	}
 	if ctx.IsSet(VMTraceFlag.Name) {
 		if name := ctx.String(VMTraceFlag.Name); name != "" {
-			var config json.RawMessage
-			if ctx.IsSet(VMTraceJsonConfigFlag.Name) {
-				config = json.RawMessage(ctx.String(VMTraceJsonConfigFlag.Name))
-			}
+			config := json.RawMessage(ctx.String(VMTraceJsonConfigFlag.Name))
 			t, err := tracers.LiveDirectory.New(name, config)
 			if err != nil {
 				Fatalf("Failed to create tracer %q: %v", name, err)

core/tracing/hooks.go

@@ -55,9 +55,8 @@ type VMContext struct {
 	Time        uint64
 	Random      *common.Hash
 	// Effective tx gas price
-	GasPrice    *big.Int
-	ChainConfig *params.ChainConfig
-	StateDB     StateDB
+	GasPrice *big.Int
+	StateDB  StateDB
 }
 
 // BlockEvent is emitted upon tracing an incoming block.

core/vm/evm.go

@@ -613,7 +613,6 @@ func (evm *EVM) GetVMContext() *tracing.VMContext {
 		Time:        evm.Context.Time,
 		Random:      evm.Context.Random,
 		GasPrice:    evm.TxContext.GasPrice,
-		ChainConfig: evm.ChainConfig(),
 		StateDB:     evm.StateDB,
 	}
 }

core/vm/runtime/runtime_test.go

@@ -395,7 +395,7 @@ func benchmarkNonModifyingCode(gas uint64, code []byte, name string, tracerCode
 	cfg.State, _ = state.New(types.EmptyRootHash, state.NewDatabaseForTesting())
 	cfg.GasLimit = gas
 	if len(tracerCode) > 0 {
-		tracer, err := tracers.DefaultDirectory.New(tracerCode, new(tracers.Context), nil)
+		tracer, err := tracers.DefaultDirectory.New(tracerCode, new(tracers.Context), nil, cfg.ChainConfig)
 		if err != nil {
 			b.Fatal(err)
 		}
@@ -887,7 +887,7 @@ func TestRuntimeJSTracer(t *testing.T) {
 			statedb.SetCode(common.HexToAddress("0xee"), calleeCode)
 			statedb.SetCode(common.HexToAddress("0xff"), suicideCode)
 
-			tracer, err := tracers.DefaultDirectory.New(jsTracer, new(tracers.Context), nil)
+			tracer, err := tracers.DefaultDirectory.New(jsTracer, new(tracers.Context), nil, params.MergedTestChainConfig)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -922,7 +922,7 @@ func TestJSTracerCreateTx(t *testing.T) {
 	code := []byte{byte(vm.PUSH1), 0, byte(vm.PUSH1), 0, byte(vm.RETURN)}
 
 	statedb, _ := state.New(types.EmptyRootHash, state.NewDatabaseForTesting())
-	tracer, err := tracers.DefaultDirectory.New(jsTracer, new(tracers.Context), nil)
+	tracer, err := tracers.DefaultDirectory.New(jsTracer, new(tracers.Context), nil, params.MergedTestChainConfig)
 	if err != nil {
 		t.Fatal(err)
 	}

eth/backend.go

@@ -197,7 +197,7 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 		}
 	)
 	if config.VMTrace != "" {
-		var traceConfig json.RawMessage
+		traceConfig := json.RawMessage("{}")
 		if config.VMTraceJsonConfig != "" {
 			traceConfig = json.RawMessage(config.VMTraceJsonConfig)
 		}

eth/tracers/api.go

@@ -1011,7 +1011,7 @@ func (api *API) traceTx(ctx context.Context, tx *types.Transaction, message *cor
 			Stop:      logger.Stop,
 		}
 	} else {
-		tracer, err = DefaultDirectory.New(*config.Tracer, txctx, config.TracerConfig)
+		tracer, err = DefaultDirectory.New(*config.Tracer, txctx, config.TracerConfig, api.backend.ChainConfig())
 		if err != nil {
 			return nil, err
 		}

eth/tracers/dir.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/tracing"
+	"github.com/ethereum/go-ethereum/params"
 )
 
 // Context contains some contextual infos for a transaction execution that is not
@@ -44,8 +45,8 @@ type Tracer struct {
 	Stop func(err error)
 }
 
-type ctorFn func(*Context, json.RawMessage) (*Tracer, error)
-type jsCtorFn func(string, *Context, json.RawMessage) (*Tracer, error)
+type ctorFn func(*Context, json.RawMessage, *params.ChainConfig) (*Tracer, error)
+type jsCtorFn func(string, *Context, json.RawMessage, *params.ChainConfig) (*Tracer, error)
 
 type elem struct {
 	ctor ctorFn
@@ -78,12 +79,15 @@ func (d *directory) RegisterJSEval(f jsCtorFn) {
 // New returns a new instance of a tracer, by iterating through the
 // registered lookups. Name is either name of an existing tracer
 // or an arbitrary JS code.
-func (d *directory) New(name string, ctx *Context, cfg json.RawMessage) (*Tracer, error) {
+func (d *directory) New(name string, ctx *Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*Tracer, error) {
+	if len(cfg) == 0 {
+		cfg = json.RawMessage("{}")
+	}
 	if elem, ok := d.elems[name]; ok {
-		return elem.ctor(ctx, cfg)
+		return elem.ctor(ctx, cfg, chainConfig)
 	}
 	// Assume JS code
-	return d.jsEval(name, ctx, cfg)
+	return d.jsEval(name, ctx, cfg, chainConfig)
 }
 
 // IsJS will return true if the given tracer will evaluate

eth/tracers/internal/tracetest/calltrace_test.go

@@ -120,7 +120,7 @@ func testCallTracer(tracerName string, dirPath string, t *testing.T) {
 			)
 			state.Close()
 
-			tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig)
+			tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig, test.Genesis.Config)
 			if err != nil {
 				t.Fatalf("failed to create call tracer: %v", err)
 			}
@@ -227,7 +227,7 @@ func benchTracer(tracerName string, test *callTracerTest, b *testing.B) {
 	b.ReportAllocs()
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), nil)
+		tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), nil, test.Genesis.Config)
 		if err != nil {
 			b.Fatalf("failed to create call tracer: %v", err)
 		}
@@ -264,7 +264,7 @@ func TestInternals(t *testing.T) {
 		}
 	)
 	mkTracer := func(name string, cfg json.RawMessage) *tracers.Tracer {
-		tr, err := tracers.DefaultDirectory.New(name, nil, cfg)
+		tr, err := tracers.DefaultDirectory.New(name, nil, cfg, config)
 		if err != nil {
 			t.Fatalf("failed to create call tracer: %v", err)
 		}

eth/tracers/internal/tracetest/flat_calltrace_test.go

@@ -89,7 +89,7 @@ func flatCallTracerTestRunner(tracerName string, filename string, dirPath string
 	defer state.Close()
 
 	// Create the tracer, the EVM environment and run it
-	tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig)
+	tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig, test.Genesis.Config)
 	if err != nil {
 		return fmt.Errorf("failed to create call tracer: %v", err)
 	}

eth/tracers/internal/tracetest/prestate_test.go

@@ -97,7 +97,7 @@ func testPrestateDiffTracer(tracerName string, dirPath string, t *testing.T) {
 			)
 			defer state.Close()
 
-			tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig)
+			tracer, err := tracers.DefaultDirectory.New(tracerName, new(tracers.Context), test.TracerConfig, test.Genesis.Config)
 			if err != nil {
 				t.Fatalf("failed to create call tracer: %v", err)
 			}

eth/tracers/js/goja.go

@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth/tracers"
 	"github.com/ethereum/go-ethereum/eth/tracers/internal"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/holiman/uint256"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -46,10 +47,10 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
-	type ctorFn = func(*tracers.Context, json.RawMessage) (*tracers.Tracer, error)
+	type ctorFn = func(*tracers.Context, json.RawMessage, *params.ChainConfig) (*tracers.Tracer, error)
 	lookup := func(code string) ctorFn {
-		return func(ctx *tracers.Context, cfg json.RawMessage) (*tracers.Tracer, error) {
-			return newJsTracer(code, ctx, cfg)
+		return func(ctx *tracers.Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*tracers.Tracer, error) {
+			return newJsTracer(code, ctx, cfg, chainConfig)
 		}
 	}
 	for name, code := range assetTracers {
@@ -102,6 +103,7 @@ func fromBuf(vm *goja.Runtime, bufType goja.Value, buf goja.Value, allowString b
 type jsTracer struct {
 	vm                *goja.Runtime
 	env               *tracing.VMContext
+	chainConfig       *params.ChainConfig
 	toBig             toBigFn               // Converts a hex string into a JS bigint
 	toBuf             toBufFn               // Converts a []byte into a JS buffer
 	fromBuf           fromBufFn             // Converts an array, hex string or Uint8Array to a []byte
@@ -138,13 +140,14 @@ type jsTracer struct {
 // The methods `result` and `fault` are required to be present.
 // The methods `step`, `enter`, and `exit` are optional, but note that
 // `enter` and `exit` always go together.
-func newJsTracer(code string, ctx *tracers.Context, cfg json.RawMessage) (*tracers.Tracer, error) {
+func newJsTracer(code string, ctx *tracers.Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*tracers.Tracer, error) {
 	vm := goja.New()
 	// By default field names are exported to JS as is, i.e. capitalized.
 	vm.SetFieldNameMapper(goja.UncapFieldNameMapper())
 	t := &jsTracer{
-		vm:  vm,
-		ctx: make(map[string]goja.Value),
+		vm:          vm,
+		ctx:         make(map[string]goja.Value),
+		chainConfig: chainConfig,
 	}
 
 	t.setTypeConverters()
@@ -244,7 +247,7 @@ func (t *jsTracer) OnTxStart(env *tracing.VMContext, tx *types.Transaction, from
 	db := &dbObj{db: env.StateDB, vm: t.vm, toBig: t.toBig, toBuf: t.toBuf, fromBuf: t.fromBuf}
 	t.dbValue = db.setupObject()
 	// Update list of precompiles based on current block
-	rules := env.ChainConfig.Rules(env.BlockNumber, env.Random != nil, env.Time)
+	rules := t.chainConfig.Rules(env.BlockNumber, env.Random != nil, env.Time)
 	t.activePrecompiles = vm.ActivePrecompiles(rules)
 	t.ctx["block"] = t.vm.ToValue(t.env.BlockNumber.Uint64())
 	t.ctx["gas"] = t.vm.ToValue(tx.Gas())