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eth/tracers: add support for block overrides in debug_traceCall (ethe…
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…reum#24871)

This PR adds support for block overrides when doing debug_traceCall.

- Previously, debug_traceCall against pending erroneously used a common.Hash{} stateroot when looking up the state, meaning that a totally empty state was used -- so it always failed,
- With this change, we reject executing debug_traceCall against pending.
- And we add ability to override all evm-visible header fields.
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@holiman
holiman authored Jun 2, 2022
1 parent f9806dc commit d8a2305
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Showing 4 changed files with 120 additions and 42 deletions.
5 changes: 5 additions & 0 deletions core/evm.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,11 @@ func GetHashFn(ref *types.Header, chain ChainContext) func(n uint64) common.Hash
var cache []common.Hash

return func(n uint64) common.Hash {
if ref.Number.Uint64() <= n {
// This situation can happen if we're doing tracing and using
// block overrides.
return common.Hash{}
}
// If there's no hash cache yet, make one
if len(cache) == 0 {
cache = append(cache, ref.ParentHash)
Expand Down
15 changes: 12 additions & 3 deletions eth/tracers/api.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -179,6 +179,7 @@ type TraceCallConfig struct {
Timeout *string
Reexec *uint64
StateOverrides *ethapi.StateOverride
BlockOverrides *ethapi.BlockOverrides
}

// StdTraceConfig holds extra parameters to standard-json trace functions.
Expand Down Expand Up @@ -806,7 +807,6 @@ func (api *API) TraceTransaction(ctx context.Context, hash common.Hash, config *
// TraceCall lets you trace a given eth_call. It collects the structured logs
// created during the execution of EVM if the given transaction was added on
// top of the provided block and returns them as a JSON object.
// You can provide -2 as a block number to trace on top of the pending block.
func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, config *TraceCallConfig) (interface{}, error) {
// Try to retrieve the specified block
var (
Expand All @@ -816,6 +816,14 @@ func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, bloc
if hash, ok := blockNrOrHash.Hash(); ok {
block, err = api.blockByHash(ctx, hash)
} else if number, ok := blockNrOrHash.Number(); ok {
if number == rpc.PendingBlockNumber {
// We don't have access to the miner here. For tracing 'future' transactions,
// it can be done with block- and state-overrides instead, which offers
// more flexibility and stability than trying to trace on 'pending', since
// the contents of 'pending' is unstable and probably not a true representation
// of what the next actual block is likely to contain.
return nil, errors.New("tracing on top of pending is not supported")
}
block, err = api.blockByNumber(ctx, number)
} else {
return nil, errors.New("invalid arguments; neither block nor hash specified")
Expand All @@ -832,18 +840,19 @@ func (api *API) TraceCall(ctx context.Context, args ethapi.TransactionArgs, bloc
if err != nil {
return nil, err
}
// Apply the customized state rules if required.
vmctx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)
// Apply the customization rules if required.
if config != nil {
if err := config.StateOverrides.Apply(statedb); err != nil {
return nil, err
}
config.BlockOverrides.Apply(&vmctx)
}
// Execute the trace
msg, err := args.ToMessage(api.backend.RPCGasCap(), block.BaseFee())
if err != nil {
return nil, err
}
vmctx := core.NewEVMBlockContext(block.Header(), api.chainContext(ctx), nil)

var traceConfig *TraceConfig
if config != nil {
Expand Down
107 changes: 68 additions & 39 deletions eth/tracers/api_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -196,13 +196,12 @@ func TestTraceCall(t *testing.T) {
tx, _ := types.SignTx(types.NewTransaction(uint64(i), accounts[1].addr, big.NewInt(1000), params.TxGas, b.BaseFee(), nil), signer, accounts[0].key)
b.AddTx(tx)
}))

var testSuite = []struct {
blockNumber rpc.BlockNumber
call ethapi.TransactionArgs
config *TraceCallConfig
expectErr error
expect interface{}
expect string
}{
// Standard JSON trace upon the genesis, plain transfer.
{
Expand All @@ -214,12 +213,7 @@ func TestTraceCall(t *testing.T) {
},
config: nil,
expectErr: nil,
expect: &logger.ExecutionResult{
Gas: params.TxGas,
Failed: false,
ReturnValue: "",
StructLogs: []logger.StructLogRes{},
},
expect: `{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}`,
},
// Standard JSON trace upon the head, plain transfer.
{
Expand All @@ -231,12 +225,7 @@ func TestTraceCall(t *testing.T) {
},
config: nil,
expectErr: nil,
expect: &logger.ExecutionResult{
Gas: params.TxGas,
Failed: false,
ReturnValue: "",
StructLogs: []logger.StructLogRes{},
},
expect: `{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}`,
},
// Standard JSON trace upon the non-existent block, error expects
{
Expand All @@ -248,7 +237,7 @@ func TestTraceCall(t *testing.T) {
},
config: nil,
expectErr: fmt.Errorf("block #%d not found", genBlocks+1),
expect: nil,
//expect: nil,
},
// Standard JSON trace upon the latest block
{
Expand All @@ -260,14 +249,9 @@ func TestTraceCall(t *testing.T) {
},
config: nil,
expectErr: nil,
expect: &logger.ExecutionResult{
Gas: params.TxGas,
Failed: false,
ReturnValue: "",
StructLogs: []logger.StructLogRes{},
},
expect: `{"gas":21000,"failed":false,"returnValue":"","structLogs":[]}`,
},
// Standard JSON trace upon the pending block
// Tracing on 'pending' should fail:
{
blockNumber: rpc.PendingBlockNumber,
call: ethapi.TransactionArgs{
Expand All @@ -276,36 +260,48 @@ func TestTraceCall(t *testing.T) {
Value: (*hexutil.Big)(big.NewInt(1000)),
},
config: nil,
expectErr: nil,
expect: &logger.ExecutionResult{
Gas: params.TxGas,
Failed: false,
ReturnValue: "",
StructLogs: []logger.StructLogRes{},
expectErr: errors.New("tracing on top of pending is not supported"),
},
{
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &accounts[0].addr,
Input: &hexutil.Bytes{0x43}, // blocknumber
},
config: &TraceCallConfig{
BlockOverrides: &ethapi.BlockOverrides{Number: (*hexutil.Big)(big.NewInt(0x1337))},
},
expectErr: nil,
expect: ` {"gas":53018,"failed":false,"returnValue":"","structLogs":[
{"pc":0,"op":"NUMBER","gas":24946984,"gasCost":2,"depth":1,"stack":[]},
{"pc":1,"op":"STOP","gas":24946982,"gasCost":0,"depth":1,"stack":["0x1337"]}]}`,
},
}
for _, testspec := range testSuite {
for i, testspec := range testSuite {
result, err := api.TraceCall(context.Background(), testspec.call, rpc.BlockNumberOrHash{BlockNumber: &testspec.blockNumber}, testspec.config)
if testspec.expectErr != nil {
if err == nil {
t.Errorf("Expect error %v, get nothing", testspec.expectErr)
t.Errorf("test %d: expect error %v, got nothing", i, testspec.expectErr)
continue
}
if !reflect.DeepEqual(err, testspec.expectErr) {
t.Errorf("Error mismatch, want %v, get %v", testspec.expectErr, err)
t.Errorf("test %d: error mismatch, want %v, git %v", i, testspec.expectErr, err)
}
} else {
if err != nil {
t.Errorf("Expect no error, get %v", err)
t.Errorf("test %d: expect no error, got %v", i, err)
continue
}
var have *logger.ExecutionResult
if err := json.Unmarshal(result.(json.RawMessage), &have); err != nil {
t.Errorf("failed to unmarshal result %v", err)
t.Errorf("test %d: failed to unmarshal result %v", i, err)
}
var want *logger.ExecutionResult
if err := json.Unmarshal([]byte(testspec.expect), &want); err != nil {
t.Errorf("test %d: failed to unmarshal result %v", i, err)
}
if !reflect.DeepEqual(have, testspec.expect) {
t.Errorf("Result mismatch, want %v, get %v", testspec.expect, have)
if !reflect.DeepEqual(have, want) {
t.Errorf("test %d: result mismatch, want %v, got %v", i, testspec.expect, string(result.(json.RawMessage)))
}
}
}
Expand Down Expand Up @@ -446,7 +442,7 @@ func TestTracingWithOverrides(t *testing.T) {
type res struct {
Gas int
Failed bool
returnValue string
ReturnValue string
}
var testSuite = []struct {
blockNumber rpc.BlockNumber
Expand All @@ -457,7 +453,7 @@ func TestTracingWithOverrides(t *testing.T) {
}{
// Call which can only succeed if state is state overridden
{
blockNumber: rpc.PendingBlockNumber,
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &randomAccounts[0].addr,
To: &randomAccounts[1].addr,
Expand All @@ -472,7 +468,7 @@ func TestTracingWithOverrides(t *testing.T) {
},
// Invalid call without state overriding
{
blockNumber: rpc.PendingBlockNumber,
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &randomAccounts[0].addr,
To: &randomAccounts[1].addr,
Expand All @@ -498,7 +494,7 @@ func TestTracingWithOverrides(t *testing.T) {
// }
// }
{
blockNumber: rpc.PendingBlockNumber,
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &randomAccounts[0].addr,
To: &randomAccounts[2].addr,
Expand All @@ -515,6 +511,39 @@ func TestTracingWithOverrides(t *testing.T) {
},
want: `{"gas":23347,"failed":false,"returnValue":"000000000000000000000000000000000000000000000000000000000000007b"}`,
},
{ // Override blocknumber
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &accounts[0].addr,
// BLOCKNUMBER PUSH1 MSTORE
Input: newRPCBytes(common.Hex2Bytes("4360005260206000f3")),
//&hexutil.Bytes{0x43}, // blocknumber
},
config: &TraceCallConfig{
BlockOverrides: &ethapi.BlockOverrides{Number: (*hexutil.Big)(big.NewInt(0x1337))},
},
want: `{"gas":59537,"failed":false,"returnValue":"0000000000000000000000000000000000000000000000000000000000001337"}`,
},
{ // Override blocknumber, and query a blockhash
blockNumber: rpc.LatestBlockNumber,
call: ethapi.TransactionArgs{
From: &accounts[0].addr,
Input: &hexutil.Bytes{
0x60, 0x00, 0x40, // BLOCKHASH(0)
0x60, 0x00, 0x52, // STORE memory offset 0
0x61, 0x13, 0x36, 0x40, // BLOCKHASH(0x1336)
0x60, 0x20, 0x52, // STORE memory offset 32
0x61, 0x13, 0x37, 0x40, // BLOCKHASH(0x1337)
0x60, 0x40, 0x52, // STORE memory offset 64
0x60, 0x60, 0x60, 0x00, 0xf3, // RETURN (0-96)

}, // blocknumber
},
config: &TraceCallConfig{
BlockOverrides: &ethapi.BlockOverrides{Number: (*hexutil.Big)(big.NewInt(0x1337))},
},
want: `{"gas":72666,"failed":false,"returnValue":"000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"}`,
},
}
for i, tc := range testSuite {
result, err := api.TraceCall(context.Background(), tc.call, rpc.BlockNumberOrHash{BlockNumber: &tc.blockNumber}, tc.config)
Expand Down
35 changes: 35 additions & 0 deletions internal/ethapi/api.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -888,6 +888,41 @@ func (diff *StateOverride) Apply(state *state.StateDB) error {
return nil
}

// BlockOverrides is a set of header fields to override.
type BlockOverrides struct {
Number *hexutil.Big
Difficulty *hexutil.Big
Time *hexutil.Big
GasLimit *hexutil.Uint64
Coinbase *common.Address
Random *common.Hash
}

// Apply overrides the given header fields into the given block context.
func (diff *BlockOverrides) Apply(blockCtx *vm.BlockContext) {
if diff == nil {
return
}
if diff.Number != nil {
blockCtx.BlockNumber = diff.Number.ToInt()
}
if diff.Difficulty != nil {
blockCtx.Difficulty = diff.Difficulty.ToInt()
}
if diff.Time != nil {
blockCtx.Time = diff.Time.ToInt()
}
if diff.GasLimit != nil {
blockCtx.GasLimit = uint64(*diff.GasLimit)
}
if diff.Coinbase != nil {
blockCtx.Coinbase = *diff.Coinbase
}
if diff.Random != nil {
blockCtx.Random = diff.Random
}
}

func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())

Expand Down

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