op-node: minimal debug-namespace RPC client bindings

op-node/sources/debug_client.go

+package sources
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+)
+
+type DebugClient struct {
+	callContext CallContextFn
+}
+
+func NewDebugClient(callContext CallContextFn) *DebugClient {
+	return &DebugClient{callContext}
+}
+
+func (o *DebugClient) NodeByHash(ctx context.Context, hash common.Hash) ([]byte, error) {
+	// MPT nodes are stored as the hash of the node (with no prefix)
+	node, err := o.dbGet(ctx, hash[:])
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve state MPT node: %w", err)
+	}
+	return node, nil
+}
+
+func (o *DebugClient) CodeByHash(ctx context.Context, hash common.Hash) ([]byte, error) {
+	// First try retrieving with the new code prefix
+	code, err := o.dbGet(ctx, append(append(make([]byte, 0), rawdb.CodePrefix...), hash[:]...))
+	if err != nil {
+		// Fallback to the legacy un-prefixed version
+		code, err = o.dbGet(ctx, hash[:])
+		if err != nil {
+			return nil, fmt.Errorf("failed to retrieve contract code, using new and legacy keys, with codehash %s: %w", hash, err)
+		}
+	}
+	return code, nil
+}
+
+func (o *DebugClient) dbGet(ctx context.Context, key []byte) ([]byte, error) {
+	var node hexutil.Bytes
+	err := o.callContext(ctx, &node, "debug_dbGet", hexutil.Encode(key))
+	if err != nil {
+		return nil, fmt.Errorf("fetch error %x: %w", key, err)
+	}
+	return node, nil
+}

op-node/testutils/mock_debug_client.go

+package testutils
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/mock"
+)
+
+type MockDebugClient struct {
+	mock.Mock
+}
+
+func (m *MockDebugClient) ExpectNodeByHash(hash common.Hash, res []byte, err error) {
+	m.Mock.On("NodeByHash", hash).Once().Return(res, &err)
+}
+
+func (m *MockDebugClient) NodeByHash(ctx context.Context, hash common.Hash) ([]byte, error) {
+	out := m.Mock.MethodCalled("NodeByHash", hash)
+	return out[0].([]byte), *out[1].(*error)
+}
+
+func (m *MockDebugClient) ExpectCodeByHash(hash common.Hash, res []byte, err error) {
+	m.Mock.On("CodeByHash", hash).Once().Return(res, &err)
+}
+
+func (m *MockDebugClient) CodeByHash(ctx context.Context, hash common.Hash) ([]byte, error) {
+	out := m.Mock.MethodCalled("CodeByHash", hash)
+	return out[0].([]byte), *out[1].(*error)
+}