op-program: Use hardcoded chain config when available

Fixes a bug where the host incorrectly informs the client that a
custom chain config is in use. The client then attempts to read the
chain config pre-image data. However, this pre-image data will not be
available in on-chain contexts.

op-program/host/config/config.go

@@ -64,6 +64,9 @@ type Config struct {
 	// ServerMode indicates that the program should run in pre-image server mode and wait for requests.
 	// No client program is run.
 	ServerMode bool
+
+	// IsCustomChainConfig indicates that the program uses a custom chain configuration
+	IsCustomChainConfig bool
 }
 
 func (c *Config) Check() error {
@@ -117,6 +120,8 @@ func NewConfig(
 	l2Claim common.Hash,
 	l2ClaimBlockNum uint64,
 ) *Config {
+	_, err := params.LoadOPStackChainConfig(l2Genesis.ChainID.Uint64())
+	isCustomConfig := err != nil
 	return &Config{
 		Rollup:              rollupCfg,
 		L2ChainConfig:       l2Genesis,
@@ -126,6 +131,7 @@ func NewConfig(
 		L2Claim:             l2Claim,
 		L2ClaimBlockNumber:  l2ClaimBlockNum,
 		L1RPCKind:           sources.RPCKindBasic,
+		IsCustomChainConfig: isCustomConfig,
 	}
 }
 
@@ -156,6 +162,7 @@ func NewConfigFromCLI(log log.Logger, ctx *cli.Context) (*Config, error) {
 	}
 	l2GenesisPath := ctx.String(flags.L2GenesisPath.Name)
 	var l2ChainConfig *params.ChainConfig
+	var isCustomConfig bool
 	if l2GenesisPath == "" {
 		networkName := ctx.String(flags.Network.Name)
 		ch := chaincfg.ChainByName(networkName)
@@ -169,6 +176,7 @@ func NewConfigFromCLI(log log.Logger, ctx *cli.Context) (*Config, error) {
 		l2ChainConfig = cfg
 	} else {
 		l2ChainConfig, err = loadChainConfigFromGenesis(l2GenesisPath)
+		isCustomConfig = true
 	}
 	if err != nil {
 		return nil, fmt.Errorf("invalid genesis: %w", err)
@@ -188,6 +196,7 @@ func NewConfigFromCLI(log log.Logger, ctx *cli.Context) (*Config, error) {
 		L1RPCKind:           sources.RPCProviderKind(ctx.String(flags.L1RPCProviderKind.Name)),
 		ExecCmd:             ctx.String(flags.Exec.Name),
 		ServerMode:          ctx.Bool(flags.Server.Name),
+		IsCustomChainConfig: isCustomConfig,
 	}, nil
 }
 

op-program/host/config/config_test.go

 package config
 
 import (
+	"math/big"
 	"testing"
 
 	"github.com/ethereum-optimism/optimism/op-node/chaincfg"
 	"github.com/ethereum-optimism/optimism/op-node/rollup"
+	"github.com/ethereum-optimism/optimism/op-program/chainconfig"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/stretchr/testify/require"
@@ -12,7 +14,7 @@ import (
 
 var (
 	validRollupConfig    = chaincfg.Goerli
-	validL2Genesis       = params.GoerliChainConfig
+	validL2Genesis       = chainconfig.OPGoerliChainConfig
 	validL1Head          = common.Hash{0xaa}
 	validL2Head          = common.Hash{0xbb}
 	validL2Claim         = common.Hash{0xcc}
@@ -158,6 +160,19 @@ func TestRejectExecAndServerMode(t *testing.T) {
 	require.ErrorIs(t, err, ErrNoExecInServerMode)
 }
 
+func TestIsCustomChainConfig(t *testing.T) {
+	t.Run("nonCustom", func(t *testing.T) {
+		cfg := validConfig()
+		require.Equal(t, cfg.IsCustomChainConfig, false)
+	})
+	t.Run("custom", func(t *testing.T) {
+		customChainConfig := &params.ChainConfig{ChainID: big.NewInt(0x1212121212)}
+		cfg := NewConfig(validRollupConfig, customChainConfig, validL1Head, validL2Head, validL2OutputRoot, validL2Claim, validL2ClaimBlockNum)
+		require.Equal(t, cfg.IsCustomChainConfig, true)
+	})
+
+}
+
 func validConfig() *Config {
 	cfg := NewConfig(validRollupConfig, validL2Genesis, validL1Head, validL2Head, validL2OutputRoot, validL2Claim, validL2ClaimBlockNum)
 	cfg.DataDir = "/tmp/configTest"

op-program/host/kvstore/local.go

@@ -38,7 +38,15 @@ func (s *LocalPreimageSource) Get(key common.Hash) ([]byte, error) {
 	case l2ClaimBlockNumberKey:
 		return binary.BigEndian.AppendUint64(nil, s.config.L2ClaimBlockNumber), nil
 	case l2ChainIDKey:
-		return binary.BigEndian.AppendUint64(nil, client.CustomChainIDIndicator), nil
+		// The CustomChainIDIndicator informs the client to rely on the L2ChainConfigKey to
+		// read the chain config. Otherwise, it'll attempt to read a non-existent hardcoded chain config
+		var chainID uint64
+		if s.config.IsCustomChainConfig {
+			chainID = client.CustomChainIDIndicator
+		} else {
+			chainID = s.config.L2ChainConfig.ChainID.Uint64()
+		}
+		return binary.BigEndian.AppendUint64(nil, chainID), nil
 	case l2ChainConfigKey:
 		return json.Marshal(s.config.L2ChainConfig)
 	case rollupKey:

op-program/host/kvstore/local_test.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/ethereum-optimism/optimism/op-node/chaincfg"
 	preimage "github.com/ethereum-optimism/optimism/op-preimage"
-	"github.com/ethereum-optimism/optimism/op-program/client"
 	"github.com/ethereum-optimism/optimism/op-program/host/config"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/params"
@@ -33,7 +32,7 @@ func TestLocalPreimageSource(t *testing.T) {
 		{"L2OutputRoot", l2OutputRootKey, cfg.L2OutputRoot.Bytes()},
 		{"L2Claim", l2ClaimKey, cfg.L2Claim.Bytes()},
 		{"L2ClaimBlockNumber", l2ClaimBlockNumberKey, binary.BigEndian.AppendUint64(nil, cfg.L2ClaimBlockNumber)},
-		{"L2ChainID", l2ChainIDKey, binary.BigEndian.AppendUint64(nil, client.CustomChainIDIndicator)},
+		{"L2ChainID", l2ChainIDKey, binary.BigEndian.AppendUint64(nil, cfg.L2ChainConfig.ChainID.Uint64())},
 		{"Rollup", rollupKey, asJson(t, cfg.Rollup)},
 		{"ChainConfig", l2ChainConfigKey, asJson(t, cfg.L2ChainConfig)},
 		{"Unknown", preimage.LocalIndexKey(1000).PreimageKey(), nil},