refactor default config

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 != "" {
-			config := json.RawMessage("{}")
+			config := json.RawMessage(ctx.String(VMTraceJsonConfigFlag.Name))
-			if ctx.IsSet(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)

eth/tracers/dir.go

@@ -80,6 +80,9 @@ func (d *directory) RegisterJSEval(f jsCtorFn) {
 // 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, chainConfig *params.ChainConfig) (*Tracer, error) {
+	if len(cfg) == 0 {
+		cfg = json.RawMessage("{}")
+	}
 	if elem, ok := d.elems[name]; ok {
 		return elem.ctor(ctx, cfg, chainConfig)
 	}

eth/tracers/live.go

@@ -40,6 +40,9 @@ func (d *liveDirectory) Register(name string, f ctorFunc) {
 
 // New instantiates a tracer by name.
 func (d *liveDirectory) New(name string, config json.RawMessage) (*tracing.Hooks, error) {
+	if len(config) == 0 {
+		config = json.RawMessage("{}")
+	}
 	if f, ok := d.elems[name]; ok {
 		return f(config)
 	}

eth/tracers/native/call.go

@@ -146,11 +146,9 @@ func newCallTracer(ctx *tracers.Context, cfg json.RawMessage, chainConfig *param
 
 func newCallTracerObject(ctx *tracers.Context, cfg json.RawMessage) (*callTracer, error) {
 	var config callTracerConfig
-	if cfg != nil {
 	if err := json.Unmarshal(cfg, &config); err != nil {
 		return nil, err
 	}
-	}
 	// First callframe contains tx context info
 	// and is populated on start and end.
 	return &callTracer{callstack: make([]callFrame, 0, 1), config: config}, nil

eth/tracers/native/call_flat.go

@@ -129,15 +129,13 @@ type flatCallTracerConfig struct {
 // newFlatCallTracer returns a new flatCallTracer.
 func newFlatCallTracer(ctx *tracers.Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*tracers.Tracer, error) {
 	var config flatCallTracerConfig
-	if cfg != nil {
 	if err := json.Unmarshal(cfg, &config); err != nil {
 		return nil, err
 	}
-	}
 
 	// Create inner call tracer with default configuration, don't forward
 	// the OnlyTopCall or WithLog to inner for now
-	t, err := newCallTracerObject(ctx, nil)
+	t, err := newCallTracerObject(ctx, json.RawMessage("{}"))
 	if err != nil {
 		return nil, err
 	}

eth/tracers/native/mux.go

@@ -41,11 +41,9 @@ type muxTracer struct {
 // newMuxTracer returns a new mux tracer.
 func newMuxTracer(ctx *tracers.Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*tracers.Tracer, error) {
 	var config map[string]json.RawMessage
-	if cfg != nil {
 	if err := json.Unmarshal(cfg, &config); err != nil {
 		return nil, err
 	}
-	}
 	objects := make([]*tracers.Tracer, 0, len(config))
 	names := make([]string, 0, len(config))
 	for k, v := range config {

eth/tracers/native/prestate.go

@@ -77,11 +77,9 @@ type prestateTracerConfig struct {
 
 func newPrestateTracer(ctx *tracers.Context, cfg json.RawMessage, chainConfig *params.ChainConfig) (*tracers.Tracer, error) {
 	var config prestateTracerConfig
-	if cfg != nil {
 	if err := json.Unmarshal(cfg, &config); err != nil {
 		return nil, err
 	}
-	}
 	t := &prestateTracer{
 		pre:     stateMap{},
 		post:    stateMap{},