feat(rpc): implement debug_executionWitness API

eth/api_debug.go

@@ -24,8 +24,10 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/stateless"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/internal/ethapi"
@@ -443,3 +445,73 @@ func (api *DebugAPI) GetTrieFlushInterval() (string, error) {
 	}
 	return api.eth.blockchain.GetTrieFlushInterval().String(), nil
 }
+
+func (api *DebugAPI) ExecutionWitness(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*ExecutionWitness, error) {
+	block, err := api.eth.APIBackend.BlockByNumberOrHash(ctx, blockNrOrHash)
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve block: %w", err)
+	}
+	if block == nil {
+		return nil, fmt.Errorf("block not found: %s", blockNrOrHash.String())
+	}
+
+	witness, err := generateWitness(api.eth.blockchain, block)
+	return ToExecutionWitness(witness), err
+}
+
+func generateWitness(blockchain *core.BlockChain, block *types.Block) (*stateless.Witness, error) {
+	witness, err := stateless.NewWitness(block.Header(), blockchain)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create witness: %w", err)
+	}
+
+	parentHeader := witness.Headers[0]
+	statedb, err := blockchain.StateAt(parentHeader.Root)
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve parent state: %w", err)
+	}
+
+	statedb.StartPrefetcher("debug_execution_witness", witness)
+	defer statedb.StopPrefetcher()
+
+	res, err := blockchain.Processor().Process(block, statedb, *blockchain.GetVMConfig())
+	if err != nil {
+		return nil, fmt.Errorf("failed to process block %d: %w", block.Number(), err)
+	}
+
+	if err := blockchain.Validator().ValidateState(block, statedb, res, false); err != nil {
+		return nil, fmt.Errorf("failed to validate block %d: %w", block.Number(), err)
+	}
+
+	return witness, nil
+}
+
+// ExecutionWitness is a witness json encoding for transferring across the network.
+// In the future, we'll probably consider using the extWitness format instead for less overhead if performance becomes an issue.
+// Currently using this format for ease of reading, parsing and compatibility across clients.
+type ExecutionWitness struct {
+	Headers []*types.Header   `json:"headers"`
+	Codes   map[string]string `json:"codes"`
+	State   map[string]string `json:"state"`
+}
+
+func transformMap(in map[string]struct{}) map[string]string {
+	out := make(map[string]string, len(in))
+	for item := range in {
+		bytes := []byte(item)
+		key := crypto.Keccak256Hash(bytes).Hex()
+		out[key] = hexutil.Encode(bytes)
+	}
+	return out
+}
+
+// ToExecutionWitness converts a witness to an execution witness format that is compatible with reth.
+// keccak(node) => node
+// keccak(bytecodes) => bytecodes
+func ToExecutionWitness(w *stateless.Witness) *ExecutionWitness {
+	return &ExecutionWitness{
+		Headers: w.Headers,
+		Codes:   transformMap(w.Codes),
+		State:   transformMap(w.State),
+	}
+}

eth/api_debug_test.go

@@ -19,20 +19,26 @@ package eth
 import (
 	"bytes"
 	"fmt"
+	"math/big"
 	"reflect"
 	"slices"
 	"strings"
 	"testing"
 
 	"github.com/davecgh/go-spew/spew"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/tracing"
 	"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/params"
 	"github.com/ethereum/go-ethereum/triedb"
 	"github.com/holiman/uint256"
+	"github.com/stretchr/testify/require"
 )
 
 var dumper = spew.ConfigState{Indent: "    "}
@@ -224,3 +230,30 @@ func TestStorageRangeAt(t *testing.T) {
 		}
 	}
 }
+
+func TestExecutionWitness(t *testing.T) {
+	t.Parallel()
+
+	// Create a database pre-initialize with a genesis block
+	db := rawdb.NewMemoryDatabase()
+	gspec := &core.Genesis{
+		Config: params.TestChainConfig,
+		Alloc:  types.GenesisAlloc{testAddr: {Balance: big.NewInt(1000000)}},
+	}
+	chain, _ := core.NewBlockChain(db, nil, gspec, nil, ethash.NewFaker(), vm.Config{}, nil)
+
+	blockNum := 10
+	_, bs, _ := core.GenerateChainWithGenesis(gspec, ethash.NewFaker(), blockNum, nil)
+	if _, err := chain.InsertChain(bs); err != nil {
+		panic(err)
+	}
+
+	block := chain.GetBlockByNumber(uint64(blockNum - 1))
+	require.NotNil(t, block)
+
+	witness, err := generateWitness(chain, block)
+	require.NoError(t, err)
+
+	_, _, err = core.ExecuteStateless(params.TestChainConfig, block, witness)
+	require.NoError(t, err)
+}