eth/tracers: package restructuring (#23857)

* eth/tracers: restructure tracer package

* core/vm/runtime: load js tracers

* eth/tracers: mv bigint js code to own file

* eth/tracers: add method docs for native tracers

* eth/tracers: minor doc fix

* core,eth: cancel evm on nativecalltracer stop

* core/vm: fix failing test
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>

cmd/geth/main.go

@@ -40,7 +40,8 @@ import (
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/node"
 
-	// Force-load the native, to trigger registration
+	// Force-load the tracer engines to trigger registration
+	_ "github.com/ethereum/go-ethereum/eth/tracers/js"
 	_ "github.com/ethereum/go-ethereum/eth/tracers/native"
 
 	"gopkg.in/urfave/cli.v1"

core/vm/access_list_tracer.go

@@ -141,7 +141,7 @@ func (a *AccessListTracer) CaptureStart(env *EVM, from common.Address, to common
 }
 
 // CaptureState captures all opcodes that touch storage or addresses and adds them to the accesslist.
-func (a *AccessListTracer) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+func (a *AccessListTracer) CaptureState(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
 	stack := scope.Stack
 	if (op == SLOAD || op == SSTORE) && stack.len() >= 1 {
 		slot := common.Hash(stack.data[stack.len()-1].Bytes32())
@@ -161,7 +161,7 @@ func (a *AccessListTracer) CaptureState(env *EVM, pc uint64, op OpCode, gas, cos
 	}
 }
 
-func (*AccessListTracer) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
+func (*AccessListTracer) CaptureFault(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 }
 
 func (*AccessListTracer) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {}

core/vm/interpreter.go

@@ -169,9 +169,9 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		defer func() {
 			if err != nil {
 				if !logged {
-					in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
+					in.cfg.Tracer.CaptureState(pcCopy, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
 				} else {
-					in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, callContext, in.evm.depth, err)
+					in.cfg.Tracer.CaptureFault(pcCopy, op, gasCopy, cost, callContext, in.evm.depth, err)
 				}
 			}
 		}()
@@ -253,7 +253,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		}
 
 		if in.cfg.Debug {
-			in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
+			in.cfg.Tracer.CaptureState(pc, op, gasCopy, cost, callContext, in.returnData, in.evm.depth, err)
 			logged = true
 		}
 

core/vm/logger.go

@@ -105,10 +105,10 @@ func (s *StructLog) ErrorString() string {
 // if you need to retain them beyond the current call.
 type EVMLogger interface {
 	CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int)
-	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error)
+	CaptureState(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error)
 	CaptureEnter(typ OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int)
 	CaptureExit(output []byte, gasUsed uint64, err error)
-	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error)
+	CaptureFault(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error)
 	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error)
 }
 
@@ -119,6 +119,7 @@ type EVMLogger interface {
 // contract their storage.
 type StructLogger struct {
 	cfg LogConfig
+	env *EVM
 
 	storage map[common.Address]Storage
 	logs    []StructLog
@@ -147,12 +148,13 @@ func (l *StructLogger) Reset() {
 
 // CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (l *StructLogger) CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	l.env = env
 }
 
 // CaptureState logs a new structured log message and pushes it out to the environment
 //
 // CaptureState also tracks SLOAD/SSTORE ops to track storage change.
-func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+func (l *StructLogger) CaptureState(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
 	memory := scope.Memory
 	stack := scope.Stack
 	contract := scope.Contract
@@ -186,7 +188,7 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 		if op == SLOAD && stack.len() >= 1 {
 			var (
 				address = common.Hash(stack.data[stack.len()-1].Bytes32())
-				value   = env.StateDB.GetState(contract.Address(), address)
+				value   = l.env.StateDB.GetState(contract.Address(), address)
 			)
 			l.storage[contract.Address()][address] = value
 			storage = l.storage[contract.Address()].Copy()
@@ -206,13 +208,13 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 		copy(rdata, rData)
 	}
 	// create a new snapshot of the EVM.
-	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, rdata, storage, depth, env.StateDB.GetRefund(), err}
+	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, rdata, storage, depth, l.env.StateDB.GetRefund(), err}
 	l.logs = append(l.logs, log)
 }
 
 // CaptureFault implements the EVMLogger interface to trace an execution fault
 // while running an opcode.
-func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
+func (l *StructLogger) CaptureFault(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 }
 
 // CaptureEnd is called after the call finishes to finalize the tracing.
@@ -291,12 +293,13 @@ func WriteLogs(writer io.Writer, logs []*types.Log) {
 type mdLogger struct {
 	out io.Writer
 	cfg *LogConfig
+	env *EVM
 }
 
 // NewMarkdownLogger creates a logger which outputs information in a format adapted
 // for human readability, and is also a valid markdown table
 func NewMarkdownLogger(cfg *LogConfig, writer io.Writer) *mdLogger {
-	l := &mdLogger{writer, cfg}
+	l := &mdLogger{out: writer, cfg: cfg}
 	if l.cfg == nil {
 		l.cfg = &LogConfig{}
 	}
@@ -304,6 +307,7 @@ func NewMarkdownLogger(cfg *LogConfig, writer io.Writer) *mdLogger {
 }
 
 func (t *mdLogger) CaptureStart(env *EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	t.env = env
 	if !create {
 		fmt.Fprintf(t.out, "From: `%v`\nTo: `%v`\nData: `0x%x`\nGas: `%d`\nValue `%v` wei\n",
 			from.String(), to.String(),
@@ -321,7 +325,7 @@ func (t *mdLogger) CaptureStart(env *EVM, from common.Address, to common.Address
 }
 
 // CaptureState also tracks SLOAD/SSTORE ops to track storage change.
-func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+func (t *mdLogger) CaptureState(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
 	stack := scope.Stack
 	fmt.Fprintf(t.out, "| %4d  | %10v  |  %3d |", pc, op, cost)
 
@@ -334,14 +338,14 @@ func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64
 		b := fmt.Sprintf("[%v]", strings.Join(a, ","))
 		fmt.Fprintf(t.out, "%10v |", b)
 	}
-	fmt.Fprintf(t.out, "%10v |", env.StateDB.GetRefund())
+	fmt.Fprintf(t.out, "%10v |", t.env.StateDB.GetRefund())
 	fmt.Fprintln(t.out, "")
 	if err != nil {
 		fmt.Fprintf(t.out, "Error: %v\n", err)
 	}
 }
 
-func (t *mdLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
+func (t *mdLogger) CaptureFault(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, depth int, err error) {
 	fmt.Fprintf(t.out, "\nError: at pc=%d, op=%v: %v\n", pc, op, err)
 }
 

core/vm/logger_json.go

@@ -29,12 +29,13 @@ import (
 type JSONLogger struct {
 	encoder *json.Encoder
 	cfg     *LogConfig
+	env     *EVM
 }
 
 // NewJSONLogger creates a new EVM tracer that prints execution steps as JSON objects
 // into the provided stream.
 func NewJSONLogger(cfg *LogConfig, writer io.Writer) *JSONLogger {
-	l := &JSONLogger{json.NewEncoder(writer), cfg}
+	l := &JSONLogger{encoder: json.NewEncoder(writer), cfg: cfg}
 	if l.cfg == nil {
 		l.cfg = &LogConfig{}
 	}
@@ -42,12 +43,13 @@ func NewJSONLogger(cfg *LogConfig, writer io.Writer) *JSONLogger {
 }
 
 func (l *JSONLogger) CaptureStart(env *EVM, from, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	l.env = env
 }
 
-func (l *JSONLogger) CaptureFault(*EVM, uint64, OpCode, uint64, uint64, *ScopeContext, int, error) {}
+func (l *JSONLogger) CaptureFault(uint64, OpCode, uint64, uint64, *ScopeContext, int, error) {}
 
 // CaptureState outputs state information on the logger.
-func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
+func (l *JSONLogger) CaptureState(pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
 	memory := scope.Memory
 	stack := scope.Stack
 
@@ -58,7 +60,7 @@ func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint
 		GasCost:       cost,
 		MemorySize:    memory.Len(),
 		Depth:         depth,
-		RefundCounter: env.StateDB.GetRefund(),
+		RefundCounter: l.env.StateDB.GetRefund(),
 		Err:           err,
 	}
 	if l.cfg.EnableMemory {

core/vm/logger_test.go

@@ -62,7 +62,8 @@ func TestStoreCapture(t *testing.T) {
 	scope.Stack.push(uint256.NewInt(1))
 	scope.Stack.push(new(uint256.Int))
 	var index common.Hash
-	logger.CaptureState(env, 0, SSTORE, 0, 0, scope, nil, 0, nil)
+	logger.CaptureStart(env, common.Address{}, contract.Address(), false, nil, 0, nil)
+	logger.CaptureState(0, SSTORE, 0, 0, scope, nil, 0, nil)
 	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()]))

core/vm/runtime/runtime_test.go

@@ -35,6 +35,9 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/eth/tracers"
 	"github.com/ethereum/go-ethereum/params"
+
+	// force-load js tracers to trigger registration
+	_ "github.com/ethereum/go-ethereum/eth/tracers/js"
 )
 
 func TestDefaults(t *testing.T) {
@@ -330,12 +333,12 @@ type stepCounter struct {
 func (s *stepCounter) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
-func (s *stepCounter) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, depth int, err error) {
+func (s *stepCounter) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, depth int, err error) {
 }
 
 func (s *stepCounter) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {}
 
-func (s *stepCounter) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+func (s *stepCounter) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
 	s.steps++
 	// Enable this for more output
 	//s.inner.CaptureState(env, pc, op, gas, cost, memory, stack, rStack, contract, depth, err)
@@ -511,7 +514,7 @@ func BenchmarkSimpleLoop(b *testing.B) {
 // TestEip2929Cases contains various testcases that are used for
 // EIP-2929 about gas repricings
 func TestEip2929Cases(t *testing.T) {
-
+	t.Skip("Test only useful for generating documentation")
 	id := 1
 	prettyPrint := func(comment string, code []byte) {
 

eth/tracers/testing/calltrace_test.go → eth/tracers/internal/tracetest/calltrace_test.go

-package testing
+// 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 tracetest
 
 import (
 	"encoding/json"
@@ -17,14 +33,67 @@ import (
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/eth/tracers"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/tests"
 
-	// Force-load the native, to trigger registration
+	// Force-load native and js pacakges, to trigger registration
+	_ "github.com/ethereum/go-ethereum/eth/tracers/js"
 	_ "github.com/ethereum/go-ethereum/eth/tracers/native"
 )
 
+// To generate a new callTracer test, copy paste the makeTest method below into
+// a Geth console and call it with a transaction hash you which to export.
+
+/*
+// makeTest generates a callTracer test by running a prestate reassembled and a
+// call trace run, assembling all the gathered information into a test case.
+var makeTest = function(tx, rewind) {
+  // Generate the genesis block from the block, transaction and prestate data
+  var block   = eth.getBlock(eth.getTransaction(tx).blockHash);
+  var genesis = eth.getBlock(block.parentHash);
+
+  delete genesis.gasUsed;
+  delete genesis.logsBloom;
+  delete genesis.parentHash;
+  delete genesis.receiptsRoot;
+  delete genesis.sha3Uncles;
+  delete genesis.size;
+  delete genesis.transactions;
+  delete genesis.transactionsRoot;
+  delete genesis.uncles;
+
+  genesis.gasLimit  = genesis.gasLimit.toString();
+  genesis.number    = genesis.number.toString();
+  genesis.timestamp = genesis.timestamp.toString();
+
+  genesis.alloc = debug.traceTransaction(tx, {tracer: "prestateTracer", rewind: rewind});
+  for (var key in genesis.alloc) {
+    genesis.alloc[key].nonce = genesis.alloc[key].nonce.toString();
+  }
+  genesis.config = admin.nodeInfo.protocols.eth.config;
+
+  // Generate the call trace and produce the test input
+  var result = debug.traceTransaction(tx, {tracer: "callTracer", rewind: rewind});
+  delete result.time;
+
+  console.log(JSON.stringify({
+    genesis: genesis,
+    context: {
+      number:     block.number.toString(),
+      difficulty: block.difficulty,
+      timestamp:  block.timestamp.toString(),
+      gasLimit:   block.gasLimit.toString(),
+      miner:      block.miner,
+    },
+    input:  eth.getRawTransaction(tx),
+    result: result,
+  }, null, 2));
+}
+*/
+
 type callContext struct {
 	Number     math.HexOrDecimal64   `json:"number"`
 	Difficulty *math.HexOrDecimal256 `json:"difficulty"`
@@ -70,7 +139,7 @@ func TestCallTracerNative(t *testing.T) {
 }
 
 func testCallTracer(tracerName string, dirPath string, t *testing.T) {
-	files, err := ioutil.ReadDir(filepath.Join("..", "testdata", dirPath))
+	files, err := ioutil.ReadDir(filepath.Join("testdata", dirPath))
 	if err != nil {
 		t.Fatalf("failed to retrieve tracer test suite: %v", err)
 	}
@@ -87,7 +156,7 @@ func testCallTracer(tracerName string, dirPath string, t *testing.T) {
 				tx   = new(types.Transaction)
 			)
 			// Call tracer test found, read if from disk
-			if blob, err := ioutil.ReadFile(filepath.Join("..", "testdata", dirPath, file.Name())); err != nil {
+			if blob, err := ioutil.ReadFile(filepath.Join("testdata", dirPath, file.Name())); err != nil {
 				t.Fatalf("failed to read testcase: %v", err)
 			} else if err := json.Unmarshal(blob, test); err != nil {
 				t.Fatalf("failed to parse testcase: %v", err)
@@ -175,7 +244,7 @@ func camel(str string) string {
 	return strings.Join(pieces, "")
 }
 func BenchmarkTracers(b *testing.B) {
-	files, err := ioutil.ReadDir(filepath.Join("..", "testdata", "call_tracer"))
+	files, err := ioutil.ReadDir(filepath.Join("testdata", "call_tracer"))
 	if err != nil {
 		b.Fatalf("failed to retrieve tracer test suite: %v", err)
 	}
@@ -185,7 +254,7 @@ func BenchmarkTracers(b *testing.B) {
 		}
 		file := file // capture range variable
 		b.Run(camel(strings.TrimSuffix(file.Name(), ".json")), func(b *testing.B) {
-			blob, err := ioutil.ReadFile(filepath.Join("..", "testdata", "call_tracer", file.Name()))
+			blob, err := ioutil.ReadFile(filepath.Join("testdata", "call_tracer", file.Name()))
 			if err != nil {
 				b.Fatalf("failed to read testcase: %v", err)
 			}
@@ -244,3 +313,82 @@ func benchTracer(tracerName string, test *callTracerTest, b *testing.B) {
 		statedb.RevertToSnapshot(snap)
 	}
 }
+
+// TestZeroValueToNotExitCall tests the calltracer(s) on the following:
+// Tx to A, A calls B with zero value. B does not already exist.
+// Expected: that enter/exit is invoked and the inner call is shown in the result
+func TestZeroValueToNotExitCall(t *testing.T) {
+	var to = common.HexToAddress("0x00000000000000000000000000000000deadbeef")
+	privkey, err := crypto.HexToECDSA("0000000000000000deadbeef00000000000000000000000000000000deadbeef")
+	if err != nil {
+		t.Fatalf("err %v", err)
+	}
+	signer := types.NewEIP155Signer(big.NewInt(1))
+	tx, err := types.SignNewTx(privkey, signer, &types.LegacyTx{
+		GasPrice: big.NewInt(0),
+		Gas:      50000,
+		To:       &to,
+	})
+	if err != nil {
+		t.Fatalf("err %v", err)
+	}
+	origin, _ := signer.Sender(tx)
+	txContext := vm.TxContext{
+		Origin:   origin,
+		GasPrice: big.NewInt(1),
+	}
+	context := vm.BlockContext{
+		CanTransfer: core.CanTransfer,
+		Transfer:    core.Transfer,
+		Coinbase:    common.Address{},
+		BlockNumber: new(big.Int).SetUint64(8000000),
+		Time:        new(big.Int).SetUint64(5),
+		Difficulty:  big.NewInt(0x30000),
+		GasLimit:    uint64(6000000),
+	}
+	var code = []byte{
+		byte(vm.PUSH1), 0x0, byte(vm.DUP1), byte(vm.DUP1), byte(vm.DUP1), // in and outs zero
+		byte(vm.DUP1), byte(vm.PUSH1), 0xff, byte(vm.GAS), // value=0,address=0xff, gas=GAS
+		byte(vm.CALL),
+	}
+	var alloc = core.GenesisAlloc{
+		to: core.GenesisAccount{
+			Nonce: 1,
+			Code:  code,
+		},
+		origin: core.GenesisAccount{
+			Nonce:   0,
+			Balance: big.NewInt(500000000000000),
+		},
+	}
+	_, statedb := tests.MakePreState(rawdb.NewMemoryDatabase(), alloc, false)
+	// Create the tracer, the EVM environment and run it
+	tracer, err := tracers.New("callTracer", nil)
+	if err != nil {
+		t.Fatalf("failed to create call tracer: %v", err)
+	}
+	evm := vm.NewEVM(context, txContext, statedb, params.MainnetChainConfig, vm.Config{Debug: true, Tracer: tracer})
+	msg, err := tx.AsMessage(signer, nil)
+	if err != nil {
+		t.Fatalf("failed to prepare transaction for tracing: %v", err)
+	}
+	st := core.NewStateTransition(evm, msg, new(core.GasPool).AddGas(tx.Gas()))
+	if _, err = st.TransitionDb(); err != nil {
+		t.Fatalf("failed to execute transaction: %v", err)
+	}
+	// Retrieve the trace result and compare against the etalon
+	res, err := tracer.GetResult()
+	if err != nil {
+		t.Fatalf("failed to retrieve trace result: %v", err)
+	}
+	have := new(callTrace)
+	if err := json.Unmarshal(res, have); err != nil {
+		t.Fatalf("failed to unmarshal trace result: %v", err)
+	}
+	wantStr := `{"type":"CALL","from":"0x682a80a6f560eec50d54e63cbeda1c324c5f8d1b","to":"0x00000000000000000000000000000000deadbeef","value":"0x0","gas":"0x7148","gasUsed":"0x2d0","input":"0x","output":"0x","calls":[{"type":"CALL","from":"0x00000000000000000000000000000000deadbeef","to":"0x00000000000000000000000000000000000000ff","value":"0x0","gas":"0x6cbf","gasUsed":"0x0","input":"0x","output":"0x"}]}`
+	want := new(callTrace)
+	json.Unmarshal([]byte(wantStr), want)
+	if !jsonEqual(have, want) {
+		t.Error("have != want")
+	}
+}

eth/tracers/tracer_test.go → eth/tracers/js/tracer_test.go

@@ -14,7 +14,7 @@
 // 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 tracers
+package js
 
 import (
 	"encoding/json"
@@ -26,6 +26,7 @@ import (
 	"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/eth/tracers"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -58,13 +59,13 @@ func testCtx() *vmContext {
 	return &vmContext{blockCtx: vm.BlockContext{BlockNumber: big.NewInt(1)}, txCtx: vm.TxContext{GasPrice: big.NewInt(100000)}}
 }
 
-func runTrace(tracer Tracer, vmctx *vmContext, chaincfg *params.ChainConfig) (json.RawMessage, error) {
-	env := vm.NewEVM(vmctx.blockCtx, vmctx.txCtx, &dummyStatedb{}, chaincfg, vm.Config{Debug: true, Tracer: tracer})
+func runTrace(tracer tracers.Tracer, vmctx *vmContext, chaincfg *params.ChainConfig) (json.RawMessage, error) {
 	var (
+		env             = vm.NewEVM(vmctx.blockCtx, vmctx.txCtx, &dummyStatedb{}, chaincfg, vm.Config{Debug: true, Tracer: tracer})
 		startGas uint64 = 10000
 		value           = big.NewInt(0)
+		contract        = vm.NewContract(account{}, account{}, value, startGas)
 	)
-	contract := vm.NewContract(account{}, account{}, value, startGas)
 	contract.Code = []byte{byte(vm.PUSH1), 0x1, byte(vm.PUSH1), 0x1, 0x0}
 
 	tracer.CaptureStart(env, contract.Caller(), contract.Address(), false, []byte{}, startGas, value)
@@ -79,14 +80,11 @@ func runTrace(tracer Tracer, vmctx *vmContext, chaincfg *params.ChainConfig) (js
 func TestTracer(t *testing.T) {
 	execTracer := func(code string) ([]byte, string) {
 		t.Helper()
-		tracer, err := New(code, new(Context))
+		tracer, err := newJsTracer(code, nil)
 		if err != nil {
 			t.Fatal(err)
 		}
-		ret, err := runTrace(tracer, &vmContext{
-			blockCtx: vm.BlockContext{BlockNumber: big.NewInt(1)},
-			txCtx:    vm.TxContext{GasPrice: big.NewInt(100000)},
-		}, params.TestChainConfig)
+		ret, err := runTrace(tracer, testCtx(), params.TestChainConfig)
 		if err != nil {
 			return nil, err.Error() // Stringify to allow comparison without nil checks
 		}
@@ -131,9 +129,8 @@ func TestTracer(t *testing.T) {
 
 func TestHalt(t *testing.T) {
 	t.Skip("duktape doesn't support abortion")
-
 	timeout := errors.New("stahp")
-	tracer, err := New("{step: function() { while(1); }, result: function() { return null; }}", new(Context))
+	tracer, err := newJsTracer("{step: function() { while(1); }, result: function() { return null; }, fault: function(){}}", nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -147,18 +144,19 @@ func TestHalt(t *testing.T) {
 }
 
 func TestHaltBetweenSteps(t *testing.T) {
-	tracer, err := New("{step: function() {}, fault: function() {}, result: function() { return null; }}", new(Context))
+	tracer, err := newJsTracer("{step: function() {}, fault: function() {}, result: function() { return null; }}", nil)
 	if err != nil {
 		t.Fatal(err)
 	}
-	env := vm.NewEVM(vm.BlockContext{BlockNumber: big.NewInt(1)}, vm.TxContext{}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
+	env := vm.NewEVM(vm.BlockContext{BlockNumber: big.NewInt(1)}, vm.TxContext{GasPrice: big.NewInt(1)}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
 	scope := &vm.ScopeContext{
 		Contract: vm.NewContract(&account{}, &account{}, big.NewInt(0), 0),
 	}
-	tracer.CaptureState(env, 0, 0, 0, 0, scope, nil, 0, nil)
+	tracer.CaptureStart(env, common.Address{}, common.Address{}, false, []byte{}, 0, big.NewInt(0))
+	tracer.CaptureState(0, 0, 0, 0, scope, nil, 0, nil)
 	timeout := errors.New("stahp")
 	tracer.Stop(timeout)
-	tracer.CaptureState(env, 0, 0, 0, 0, scope, nil, 0, nil)
+	tracer.CaptureState(0, 0, 0, 0, scope, nil, 0, nil)
 
 	if _, err := tracer.GetResult(); err.Error() != timeout.Error() {
 		t.Errorf("Expected timeout error, got %v", err)
@@ -168,24 +166,16 @@ func TestHaltBetweenSteps(t *testing.T) {
 // TestNoStepExec tests a regular value transfer (no exec), and accessing the statedb
 // in 'result'
 func TestNoStepExec(t *testing.T) {
-	runEmptyTrace := func(tracer Tracer, vmctx *vmContext) (json.RawMessage, error) {
-		env := vm.NewEVM(vmctx.blockCtx, vmctx.txCtx, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
-		startGas := uint64(10000)
-		contract := vm.NewContract(account{}, account{}, big.NewInt(0), startGas)
-		tracer.CaptureStart(env, contract.Caller(), contract.Address(), false, []byte{}, startGas, big.NewInt(0))
-		tracer.CaptureEnd(nil, startGas-contract.Gas, 1, nil)
-		return tracer.GetResult()
-	}
 	execTracer := func(code string) []byte {
 		t.Helper()
-		tracer, err := New(code, new(Context))
+		tracer, err := newJsTracer(code, nil)
 		if err != nil {
 			t.Fatal(err)
 		}
-		ret, err := runEmptyTrace(tracer, &vmContext{
-			blockCtx: vm.BlockContext{BlockNumber: big.NewInt(1)},
-			txCtx:    vm.TxContext{GasPrice: big.NewInt(100000)},
-		})
+		env := vm.NewEVM(vm.BlockContext{BlockNumber: big.NewInt(1)}, vm.TxContext{GasPrice: big.NewInt(100)}, &dummyStatedb{}, params.TestChainConfig, vm.Config{Debug: true, Tracer: tracer})
+		tracer.CaptureStart(env, common.Address{}, common.Address{}, false, []byte{}, 1000, big.NewInt(0))
+		tracer.CaptureEnd(nil, 0, 1, nil)
+		ret, err := tracer.GetResult()
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -212,7 +202,7 @@ func TestIsPrecompile(t *testing.T) {
 	chaincfg.IstanbulBlock = big.NewInt(200)
 	chaincfg.BerlinBlock = big.NewInt(300)
 	txCtx := vm.TxContext{GasPrice: big.NewInt(100000)}
-	tracer, err := New("{addr: toAddress('0000000000000000000000000000000000000009'), res: null, step: function() { this.res = isPrecompiled(this.addr); }, fault: function() {}, result: function() { return this.res; }}", new(Context))
+	tracer, err := newJsTracer("{addr: toAddress('0000000000000000000000000000000000000009'), res: null, step: function() { this.res = isPrecompiled(this.addr); }, fault: function() {}, result: function() { return this.res; }}", nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -226,7 +216,7 @@ func TestIsPrecompile(t *testing.T) {
 		t.Errorf("Tracer should not consider blake2f as precompile in byzantium")
 	}
 
-	tracer, _ = New("{addr: toAddress('0000000000000000000000000000000000000009'), res: null, step: function() { this.res = isPrecompiled(this.addr); }, fault: function() {}, result: function() { return this.res; }}", new(Context))
+	tracer, _ = newJsTracer("{addr: toAddress('0000000000000000000000000000000000000009'), res: null, step: function() { this.res = isPrecompiled(this.addr); }, fault: function() {}, result: function() { return this.res; }}", nil)
 	blockCtx = vm.BlockContext{BlockNumber: big.NewInt(250)}
 	res, err = runTrace(tracer, &vmContext{blockCtx, txCtx}, chaincfg)
 	if err != nil {
@@ -239,23 +229,20 @@ func TestIsPrecompile(t *testing.T) {
 
 func TestEnterExit(t *testing.T) {
 	// test that either both or none of enter() and exit() are defined
-	if _, err := New("{step: function() {}, fault: function() {}, result: function() { return null; }, enter: function() {}}", new(Context)); err == nil {
+	if _, err := newJsTracer("{step: function() {}, fault: function() {}, result: function() { return null; }, enter: function() {}}", new(tracers.Context)); err == nil {
 		t.Fatal("tracer creation should've failed without exit() definition")
 	}
-	if _, err := New("{step: function() {}, fault: function() {}, result: function() { return null; }, enter: function() {}, exit: function() {}}", new(Context)); err != nil {
+	if _, err := newJsTracer("{step: function() {}, fault: function() {}, result: function() { return null; }, enter: function() {}, exit: function() {}}", new(tracers.Context)); err != nil {
 		t.Fatal(err)
 	}
-
 	// test that the enter and exit method are correctly invoked and the values passed
-	tracer, err := New("{enters: 0, exits: 0, enterGas: 0, gasUsed: 0, step: function() {}, fault: function() {}, result: function() { return {enters: this.enters, exits: this.exits, enterGas: this.enterGas, gasUsed: this.gasUsed} }, enter: function(frame) { this.enters++; this.enterGas = frame.getGas(); }, exit: function(res) { this.exits++; this.gasUsed = res.getGasUsed(); }}", new(Context))
+	tracer, err := newJsTracer("{enters: 0, exits: 0, enterGas: 0, gasUsed: 0, step: function() {}, fault: function() {}, result: function() { return {enters: this.enters, exits: this.exits, enterGas: this.enterGas, gasUsed: this.gasUsed} }, enter: function(frame) { this.enters++; this.enterGas = frame.getGas(); }, exit: function(res) { this.exits++; this.gasUsed = res.getGasUsed(); }}", new(tracers.Context))
 	if err != nil {
 		t.Fatal(err)
 	}
-
 	scope := &vm.ScopeContext{
 		Contract: vm.NewContract(&account{}, &account{}, big.NewInt(0), 0),
 	}
-
 	tracer.CaptureEnter(vm.CALL, scope.Contract.Caller(), scope.Contract.Address(), []byte{}, 1000, new(big.Int))
 	tracer.CaptureExit([]byte{}, 400, nil)
 

eth/tracers/native/call.go

@@ -31,7 +31,7 @@ import (
 )
 
 func init() {
-	tracers.RegisterNativeTracer("callTracer", NewCallTracer)
+	register("callTracer", newCallTracer)
 }
 
 type callFrame struct {
@@ -48,21 +48,24 @@ type callFrame struct {
 }
 
 type callTracer struct {
+	env       *vm.EVM
 	callstack []callFrame
 	interrupt uint32 // Atomic flag to signal execution interruption
 	reason    error  // Textual reason for the interruption
 }
 
-// NewCallTracer returns a native go tracer which tracks
+// newCallTracer returns a native go tracer which tracks
 // call frames of a tx, and implements vm.EVMLogger.
-func NewCallTracer() tracers.Tracer {
+func newCallTracer() tracers.Tracer {
 	// First callframe contains tx context info
 	// and is populated on start and end.
 	t := &callTracer{callstack: make([]callFrame, 1)}
 	return t
 }
 
+// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (t *callTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
+	t.env = env
 	t.callstack[0] = callFrame{
 		Type:  "CALL",
 		From:  addrToHex(from),
@@ -76,6 +79,7 @@ func (t *callTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Ad
 	}
 }
 
+// CaptureEnd is called after the call finishes to finalize the tracing.
 func (t *callTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration, err error) {
 	t.callstack[0].GasUsed = uintToHex(gasUsed)
 	if err != nil {
@@ -88,16 +92,19 @@ func (t *callTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration,
 	}
 }
 
-func (t *callTracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+// CaptureState implements the EVMLogger interface to trace a single step of VM execution.
+func (t *callTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
 }
 
-func (t *callTracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
+// CaptureFault implements the EVMLogger interface to trace an execution fault.
+func (t *callTracer) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
 }
 
+// CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
 func (t *callTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
 	// Skip if tracing was interrupted
 	if atomic.LoadUint32(&t.interrupt) > 0 {
-		// TODO: env.Cancel()
+		t.env.Cancel()
 		return
 	}
 
@@ -112,6 +119,8 @@ func (t *callTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.
 	t.callstack = append(t.callstack, call)
 }
 
+// CaptureExit is called when EVM exits a scope, even if the scope didn't
+// execute any code.
 func (t *callTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
 	size := len(t.callstack)
 	if size <= 1 {
@@ -134,6 +143,8 @@ func (t *callTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
 	t.callstack[size-1].Calls = append(t.callstack[size-1].Calls, call)
 }
 
+// GetResult returns the json-encoded nested list of call traces, and any
+// error arising from the encoding or forceful termination (via `Stop`).
 func (t *callTracer) GetResult() (json.RawMessage, error) {
 	if len(t.callstack) != 1 {
 		return nil, errors.New("incorrect number of top-level calls")
@@ -145,6 +156,7 @@ func (t *callTracer) GetResult() (json.RawMessage, error) {
 	return json.RawMessage(res), t.reason
 }
 
+// Stop terminates execution of the tracer at the first opportune moment.
 func (t *callTracer) Stop(err error) {
 	t.reason = err
 	atomic.StoreUint32(&t.interrupt, 1)

eth/tracers/native/noop.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 native
 
 import (
@@ -11,36 +27,48 @@ import (
 )
 
 func init() {
-	tracers.RegisterNativeTracer("noopTracerNative", NewNoopTracer)
+	register("noopTracerNative", newNoopTracer)
 }
 
+// noopTracer is a go implementation of the Tracer interface which
+// performs no action. It's mostly useful for testing purposes.
 type noopTracer struct{}
 
-func NewNoopTracer() tracers.Tracer {
+// newNoopTracer returns a new noop tracer.
+func newNoopTracer() tracers.Tracer {
 	return &noopTracer{}
 }
 
+// CaptureStart implements the EVMLogger interface to initialize the tracing operation.
 func (t *noopTracer) CaptureStart(env *vm.EVM, from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
 }
 
+// CaptureEnd is called after the call finishes to finalize the tracing.
 func (t *noopTracer) CaptureEnd(output []byte, gasUsed uint64, _ time.Duration, err error) {
 }
 
-func (t *noopTracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
+// CaptureState implements the EVMLogger interface to trace a single step of VM execution.
+func (t *noopTracer) CaptureState(pc uint64, op vm.OpCode, gas, cost uint64, scope *vm.ScopeContext, rData []byte, depth int, err error) {
 }
 
-func (t *noopTracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
+// CaptureFault implements the EVMLogger interface to trace an execution fault.
+func (t *noopTracer) CaptureFault(pc uint64, op vm.OpCode, gas, cost uint64, _ *vm.ScopeContext, depth int, err error) {
 }
 
+// CaptureEnter is called when EVM enters a new scope (via call, create or selfdestruct).
 func (t *noopTracer) CaptureEnter(typ vm.OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
 }
 
+// CaptureExit is called when EVM exits a scope, even if the scope didn't
+// execute any code.
 func (t *noopTracer) CaptureExit(output []byte, gasUsed uint64, err error) {
 }
 
+// GetResult returns an empty json object.
 func (t *noopTracer) GetResult() (json.RawMessage, error) {
 	return json.RawMessage(`{}`), nil
 }
 
+// Stop terminates execution of the tracer at the first opportune moment.
 func (t *noopTracer) Stop(err error) {
 }

eth/tracers/native/tracer.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 native is a collection of tracers written in go.
+
+In order to add a native tracer and have it compiled into the binary, a new
+file needs to be added to this folder, containing an implementation of the
+`eth.tracers.Tracer` interface.
+
+Aside from implementing the tracer, it also needs to register itself, using the
+`register` method -- and this needs to be done in the package initialization.
+
+Example:
+
+```golang
+func init() {
+	register("noopTracerNative", newNoopTracer)
+}
+```
+*/
+package native
+
+import (
+	"errors"
+
+	"github.com/ethereum/go-ethereum/eth/tracers"
+)
+
+// init registers itself this packages as a lookup for tracers.
+func init() {
+	tracers.RegisterLookup(false, lookup)
+}
+
+/*
+ctors is a map of package-local tracer constructors.
+
+We cannot be certain about the order of init-functions within a package,
+The go spec (https://golang.org/ref/spec#Package_initialization) says
+
+> To ensure reproducible initialization behavior, build systems
+> are encouraged to present multiple files belonging to the same
+> package in lexical file name order to a compiler.
+
+Hence, we cannot make the map in init, but must make it upon first use.
+*/
+var ctors map[string]func() tracers.Tracer
+
+// register is used by native tracers to register their presence.
+func register(name string, ctor func() tracers.Tracer) {
+	if ctors == nil {
+		ctors = make(map[string]func() tracers.Tracer)
+	}
+	ctors[name] = ctor
+}
+
+// lookup returns a tracer, if one can be matched to the given name.
+func lookup(name string, ctx *tracers.Context) (tracers.Tracer, error) {
+	if ctors == nil {
+		ctors = make(map[string]func() tracers.Tracer)
+	}
+	if ctor, ok := ctors[name]; ok {
+		return ctor(), nil
+	}
+	return nil, errors.New("no tracer found")
+}

eth/tracers/tracers.go

@@ -14,18 +14,25 @@
 // 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 tracers is a collection of JavaScript transaction tracers.
+// Package tracers is a manager for transaction tracing engines.
 package tracers
 
 import (
 	"encoding/json"
-	"strings"
-	"unicode"
+	"errors"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/vm"
-	"github.com/ethereum/go-ethereum/eth/tracers/internal/tracers"
 )
 
+// Context contains some contextual infos for a transaction execution that is not
+// available from within the EVM object.
+type Context struct {
+	BlockHash common.Hash // Hash of the block the tx is contained within (zero if dangling tx or call)
+	TxIndex   int         // Index of the transaction within a block (zero if dangling tx or call)
+	TxHash    common.Hash // Hash of the transaction being traced (zero if dangling call)
+}
+
 // Tracer interface extends vm.EVMLogger and additionally
 // allows collecting the tracing result.
 type Tracer interface {
@@ -35,50 +42,31 @@ type Tracer interface {
 	Stop(err error)
 }
 
+type lookupFunc func(string, *Context) (Tracer, error)
+
 var (
-	nativeTracers map[string]func() Tracer = make(map[string]func() Tracer)
-	jsTracers                              = make(map[string]string)
+	lookups []lookupFunc
 )
 
-// RegisterNativeTracer makes native tracers which adhere
-// to the `Tracer` interface available to the rest of the codebase.
-// It is typically invoked in the `init()` function, e.g. see the `native/call.go`.
-func RegisterNativeTracer(name string, ctor func() Tracer) {
-	nativeTracers[name] = ctor
-}
-
-// New returns a new instance of a tracer,
-// 1. If 'code' is the name of a registered native tracer, then that tracer
-//   is instantiated and returned
-// 2. If 'code' is the name of a registered js-tracer, then that tracer is
-//   instantiated and returned
-// 3. Otherwise, the code is interpreted as the js code of a js-tracer, and
-//   is evaluated and returned.
-func New(code string, ctx *Context) (Tracer, error) {
-	// Resolve native tracer
-	if fn, ok := nativeTracers[code]; ok {
-		return fn(), nil
+// RegisterLookup registers a method as a lookup for tracers, meaning that
+// users can invoke a named tracer through that lookup. If 'wildcard' is true,
+// then the lookup will be placed last. This is typically meant for interpreted
+// engines (js) which can evaluate dynamic user-supplied code.
+func RegisterLookup(wildcard bool, lookup lookupFunc) {
+	if wildcard {
+		lookups = append(lookups, lookup)
+	} else {
+		lookups = append([]lookupFunc{lookup}, lookups...)
 	}
-	// Resolve js-tracers by name and assemble the tracer object
-	if tracer, ok := jsTracers[code]; ok {
-		code = tracer
-	}
-	return newJsTracer(code, ctx)
 }
 
-// camel converts a snake cased input string into a camel cased output.
-func camel(str string) string {
-	pieces := strings.Split(str, "_")
-	for i := 1; i < len(pieces); i++ {
-		pieces[i] = string(unicode.ToUpper(rune(pieces[i][0]))) + pieces[i][1:]
-	}
-	return strings.Join(pieces, "")
-}
-
-// init retrieves the JavaScript transaction tracers included in go-ethereum.
-func init() {
-	for _, file := range tracers.AssetNames() {
-		name := camel(strings.TrimSuffix(file, ".js"))
-		jsTracers[name] = string(tracers.MustAsset(file))
+// New returns a new instance of a tracer, by iterating through the
+// registered lookups.
+func New(code string, ctx *Context) (Tracer, error) {
+	for _, lookup := range lookups {
+		if tracer, err := lookup(code, ctx); err == nil {
+			return tracer, nil
+		}
 	}
+	return nil, errors.New("tracer not found")
 }

eth/tracers/tracers_test.go

@@ -17,11 +17,7 @@
 package tracers
 
 import (
-	"crypto/ecdsa"
-	"crypto/rand"
-	"encoding/json"
 	"math/big"
-	"reflect"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -35,56 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/tests"
 )
 
-// To generate a new callTracer test, copy paste the makeTest method below into
-// a Geth console and call it with a transaction hash you which to export.
-
-/*
-// makeTest generates a callTracer test by running a prestate reassembled and a
-// call trace run, assembling all the gathered information into a test case.
-var makeTest = function(tx, rewind) {
-  // Generate the genesis block from the block, transaction and prestate data
-  var block   = eth.getBlock(eth.getTransaction(tx).blockHash);
-  var genesis = eth.getBlock(block.parentHash);
-
-  delete genesis.gasUsed;
-  delete genesis.logsBloom;
-  delete genesis.parentHash;
-  delete genesis.receiptsRoot;
-  delete genesis.sha3Uncles;
-  delete genesis.size;
-  delete genesis.transactions;
-  delete genesis.transactionsRoot;
-  delete genesis.uncles;
-
-  genesis.gasLimit  = genesis.gasLimit.toString();
-  genesis.number    = genesis.number.toString();
-  genesis.timestamp = genesis.timestamp.toString();
-
-  genesis.alloc = debug.traceTransaction(tx, {tracer: "prestateTracer", rewind: rewind});
-  for (var key in genesis.alloc) {
-    genesis.alloc[key].nonce = genesis.alloc[key].nonce.toString();
-  }
-  genesis.config = admin.nodeInfo.protocols.eth.config;
-
-  // Generate the call trace and produce the test input
-  var result = debug.traceTransaction(tx, {tracer: "callTracer", rewind: rewind});
-  delete result.time;
-
-  console.log(JSON.stringify({
-    genesis: genesis,
-    context: {
-      number:     block.number.toString(),
-      difficulty: block.difficulty,
-      timestamp:  block.timestamp.toString(),
-      gasLimit:   block.gasLimit.toString(),
-      miner:      block.miner,
-    },
-    input:  eth.getRawTransaction(tx),
-    result: result,
-  }, null, 2));
-}
-*/
-
 // callTrace is the result of a callTracer run.
 type callTrace struct {
 	Type    string          `json:"type"`
@@ -99,184 +45,6 @@ type callTrace struct {
 	Calls   []callTrace     `json:"calls,omitempty"`
 }
 
-// TestZeroValueToNotExitCall tests the calltracer(s) on the following:
-// Tx to A, A calls B with zero value. B does not already exist.
-// Expected: that enter/exit is invoked and the inner call is shown in the result
-func TestZeroValueToNotExitCall(t *testing.T) {
-	var to = common.HexToAddress("0x00000000000000000000000000000000deadbeef")
-	privkey, err := crypto.HexToECDSA("0000000000000000deadbeef00000000000000000000000000000000deadbeef")
-	if err != nil {
-		t.Fatalf("err %v", err)
-	}
-	signer := types.NewEIP155Signer(big.NewInt(1))
-	tx, err := types.SignNewTx(privkey, signer, &types.LegacyTx{
-		GasPrice: big.NewInt(0),
-		Gas:      50000,
-		To:       &to,
-	})
-	if err != nil {
-		t.Fatalf("err %v", err)
-	}
-	origin, _ := signer.Sender(tx)
-	txContext := vm.TxContext{
-		Origin:   origin,
-		GasPrice: big.NewInt(1),
-	}
-	context := vm.BlockContext{
-		CanTransfer: core.CanTransfer,
-		Transfer:    core.Transfer,
-		Coinbase:    common.Address{},
-		BlockNumber: new(big.Int).SetUint64(8000000),
-		Time:        new(big.Int).SetUint64(5),
-		Difficulty:  big.NewInt(0x30000),
-		GasLimit:    uint64(6000000),
-	}
-	var code = []byte{
-		byte(vm.PUSH1), 0x0, byte(vm.DUP1), byte(vm.DUP1), byte(vm.DUP1), // in and outs zero
-		byte(vm.DUP1), byte(vm.PUSH1), 0xff, byte(vm.GAS), // value=0,address=0xff, gas=GAS
-		byte(vm.CALL),
-	}
-	var alloc = core.GenesisAlloc{
-		to: core.GenesisAccount{
-			Nonce: 1,
-			Code:  code,
-		},
-		origin: core.GenesisAccount{
-			Nonce:   0,
-			Balance: big.NewInt(500000000000000),
-		},
-	}
-	_, statedb := tests.MakePreState(rawdb.NewMemoryDatabase(), alloc, false)
-	// Create the tracer, the EVM environment and run it
-	tracer, err := New("callTracerJs", new(Context))
-	if err != nil {
-		t.Fatalf("failed to create call tracer: %v", err)
-	}
-	evm := vm.NewEVM(context, txContext, statedb, params.MainnetChainConfig, vm.Config{Debug: true, Tracer: tracer})
-	msg, err := tx.AsMessage(signer, nil)
-	if err != nil {
-		t.Fatalf("failed to prepare transaction for tracing: %v", err)
-	}
-	st := core.NewStateTransition(evm, msg, new(core.GasPool).AddGas(tx.Gas()))
-	if _, err = st.TransitionDb(); err != nil {
-		t.Fatalf("failed to execute transaction: %v", err)
-	}
-	// Retrieve the trace result and compare against the etalon
-	res, err := tracer.GetResult()
-	if err != nil {
-		t.Fatalf("failed to retrieve trace result: %v", err)
-	}
-	have := new(callTrace)
-	if err := json.Unmarshal(res, have); err != nil {
-		t.Fatalf("failed to unmarshal trace result: %v", err)
-	}
-	wantStr := `{"type":"CALL","from":"0x682a80a6f560eec50d54e63cbeda1c324c5f8d1b","to":"0x00000000000000000000000000000000deadbeef","value":"0x0","gas":"0x7148","gasUsed":"0x2d0","input":"0x","output":"0x","calls":[{"type":"CALL","from":"0x00000000000000000000000000000000deadbeef","to":"0x00000000000000000000000000000000000000ff","value":"0x0","gas":"0x6cbf","gasUsed":"0x0","input":"0x","output":"0x"}]}`
-	want := new(callTrace)
-	json.Unmarshal([]byte(wantStr), want)
-	if !jsonEqual(have, want) {
-		t.Error("have != want")
-	}
-}
-
-func TestPrestateTracerCreate2(t *testing.T) {
-	unsignedTx := types.NewTransaction(1, common.HexToAddress("0x00000000000000000000000000000000deadbeef"),
-		new(big.Int), 5000000, big.NewInt(1), []byte{})
-
-	privateKeyECDSA, err := ecdsa.GenerateKey(crypto.S256(), rand.Reader)
-	if err != nil {
-		t.Fatalf("err %v", err)
-	}
-	signer := types.NewEIP155Signer(big.NewInt(1))
-	tx, err := types.SignTx(unsignedTx, signer, privateKeyECDSA)
-	if err != nil {
-		t.Fatalf("err %v", err)
-	}
-	/**
-		This comes from one of the test-vectors on the Skinny Create2 - EIP
-
-	    address 0x00000000000000000000000000000000deadbeef
-	    salt 0x00000000000000000000000000000000000000000000000000000000cafebabe
-	    init_code 0xdeadbeef
-	    gas (assuming no mem expansion): 32006
-	    result: 0x60f3f640a8508fC6a86d45DF051962668E1e8AC7
-	*/
-	origin, _ := signer.Sender(tx)
-	txContext := vm.TxContext{
-		Origin:   origin,
-		GasPrice: big.NewInt(1),
-	}
-	context := vm.BlockContext{
-		CanTransfer: core.CanTransfer,
-		Transfer:    core.Transfer,
-		Coinbase:    common.Address{},
-		BlockNumber: new(big.Int).SetUint64(8000000),
-		Time:        new(big.Int).SetUint64(5),
-		Difficulty:  big.NewInt(0x30000),
-		GasLimit:    uint64(6000000),
-	}
-	alloc := core.GenesisAlloc{}
-
-	// The code pushes 'deadbeef' into memory, then the other params, and calls CREATE2, then returns
-	// the address
-	alloc[common.HexToAddress("0x00000000000000000000000000000000deadbeef")] = core.GenesisAccount{
-		Nonce:   1,
-		Code:    hexutil.MustDecode("0x63deadbeef60005263cafebabe6004601c6000F560005260206000F3"),
-		Balance: big.NewInt(1),
-	}
-	alloc[origin] = core.GenesisAccount{
-		Nonce:   1,
-		Code:    []byte{},
-		Balance: big.NewInt(500000000000000),
-	}
-	_, statedb := tests.MakePreState(rawdb.NewMemoryDatabase(), alloc, false)
-
-	// Create the tracer, the EVM environment and run it
-	tracer, err := New("prestateTracer", new(Context))
-	if err != nil {
-		t.Fatalf("failed to create call tracer: %v", err)
-	}
-	evm := vm.NewEVM(context, txContext, statedb, params.MainnetChainConfig, vm.Config{Debug: true, Tracer: tracer})
-
-	msg, err := tx.AsMessage(signer, nil)
-	if err != nil {
-		t.Fatalf("failed to prepare transaction for tracing: %v", err)
-	}
-	st := core.NewStateTransition(evm, msg, new(core.GasPool).AddGas(tx.Gas()))
-	if _, err = st.TransitionDb(); err != nil {
-		t.Fatalf("failed to execute transaction: %v", err)
-	}
-	// Retrieve the trace result and compare against the etalon
-	res, err := tracer.GetResult()
-	if err != nil {
-		t.Fatalf("failed to retrieve trace result: %v", err)
-	}
-	ret := make(map[string]interface{})
-	if err := json.Unmarshal(res, &ret); err != nil {
-		t.Fatalf("failed to unmarshal trace result: %v", err)
-	}
-	if _, has := ret["0x60f3f640a8508fc6a86d45df051962668e1e8ac7"]; !has {
-		t.Fatalf("Expected 0x60f3f640a8508fc6a86d45df051962668e1e8ac7 in result")
-	}
-}
-
-// jsonEqual is similar to reflect.DeepEqual, but does a 'bounce' via json prior to
-// comparison
-func jsonEqual(x, y interface{}) bool {
-	xTrace := new(callTrace)
-	yTrace := new(callTrace)
-	if xj, err := json.Marshal(x); err == nil {
-		json.Unmarshal(xj, xTrace)
-	} else {
-		return false
-	}
-	if yj, err := json.Marshal(y); err == nil {
-		json.Unmarshal(yj, yTrace)
-	} else {
-		return false
-	}
-	return reflect.DeepEqual(xTrace, yTrace)
-}
-
 func BenchmarkTransactionTrace(b *testing.B) {
 	key, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 	from := crypto.PubkeyToAddress(key.PublicKey)