Merge pull request #5335 from ethereum-optimism/aj/refactor-engine-api

op-e2e: Separate engine API implementation from backend

op-e2e/actions/l2_batcher_test.go

@@ -447,7 +447,7 @@ func TestBigL2Txs(gt *testing.T) {
 			require.NoError(t, err)
 			gas, err := core.IntrinsicGas(data, nil, false, true, true, false)
 			require.NoError(t, err)
-			if gas > engine.l2GasPool.Gas() {
+			if gas > engine.engineApi.RemainingBlockGas() {
 				break
 			}
 			tx := types.MustSignNewTx(dp.Secrets.Alice, signer, &types.DynamicFeeTx{

op-e2e/actions/l2_engine.go

@@ -3,12 +3,12 @@ package actions
 import (
 	"errors"
 
+	"github.com/ethereum-optimism/optimism/op-e2e/e2eutils"
+	"github.com/ethereum-optimism/optimism/op-program/l2/engineapi"
 	"github.com/stretchr/testify/require"
 
-	"github.com/ethereum/go-ethereum/beacon/engine"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	geth "github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
@@ -39,21 +39,9 @@ type L2Engine struct {
 
 	// L2 evm / chain
 	l2Chain  *core.BlockChain
-	l2Database ethdb.Database
-	l2Cfg      *core.Genesis
 	l2Signer types.Signer
 
-	// L2 block building data
-	l2BuildingHeader *types.Header             // block header that we add txs to for block building
-	l2BuildingState  *state.StateDB            // state used for block building
-	l2GasPool        *core.GasPool             // track gas used of ongoing building
-	pendingIndices   map[common.Address]uint64 // per account, how many txs from the pool were already included in the block, since the pool is lagging behind block mining.
-	l2Transactions   []*types.Transaction      // collects txs that were successfully included into current block build
-	l2Receipts       []*types.Receipt          // collect receipts of ongoing building
-	l2ForceEmpty     bool                      // when no additional txs may be processed (i.e. when sequencer drift runs out)
-	l2TxFailed       []*types.Transaction      // log of failed transactions which could not be included
-
-	payloadID engine.PayloadID // ID of payload that is currently being built
+	engineApi *engineapi.L2EngineAPI
 
 	failL2RPC error // mock error
 }
@@ -61,6 +49,38 @@ type L2Engine struct {
 type EngineOption func(ethCfg *ethconfig.Config, nodeCfg *node.Config) error
 
 func NewL2Engine(t Testing, log log.Logger, genesis *core.Genesis, rollupGenesisL1 eth.BlockID, jwtPath string, options ...EngineOption) *L2Engine {
+	n, ethBackend, apiBackend := newBackend(t, genesis, jwtPath, options)
+	engineApi := engineapi.NewL2EngineAPI(log, apiBackend)
+	chain := ethBackend.BlockChain()
+	genesisBlock := chain.Genesis()
+	eng := &L2Engine{
+		log:  log,
+		node: n,
+		eth:  ethBackend,
+		rollupGenesis: &rollup.Genesis{
+			L1:     rollupGenesisL1,
+			L2:     eth.BlockID{Hash: genesisBlock.Hash(), Number: genesisBlock.NumberU64()},
+			L2Time: genesis.Timestamp,
+		},
+		l2Chain:   chain,
+		l2Signer:  types.LatestSigner(genesis.Config),
+		engineApi: engineApi,
+	}
+	// register the custom engine API, so we can serve engine requests while having more control
+	// over sequencing of individual txs.
+	n.RegisterAPIs([]rpc.API{
+		{
+			Namespace:     "engine",
+			Service:       eng.engineApi,
+			Authenticated: true,
+		},
+	})
+	require.NoError(t, n.Start(), "failed to start L2 op-geth node")
+
+	return eng
+}
+
+func newBackend(t e2eutils.TestingBase, genesis *core.Genesis, jwtPath string, options []EngineOption) (*node.Node, *geth.Ethereum, *engineApiBackend) {
 	ethCfg := &ethconfig.Config{
 		NetworkId: genesis.Config.ChainID.Uint64(),
 		Genesis:   genesis,
@@ -89,33 +109,26 @@ func NewL2Engine(t Testing, log log.Logger, genesis *core.Genesis, rollupGenesis
 
 	chain := backend.BlockChain()
 	db := backend.ChainDb()
-	genesisBlock := chain.Genesis()
-	eng := &L2Engine{
-		log:  log,
-		node: n,
-		eth:  backend,
-		rollupGenesis: &rollup.Genesis{
-			L1:     rollupGenesisL1,
-			L2:     eth.BlockID{Hash: genesisBlock.Hash(), Number: genesisBlock.NumberU64()},
-			L2Time: genesis.Timestamp,
-		},
-		l2Chain:    chain,
-		l2Database: db,
-		l2Cfg:      genesis,
-		l2Signer:   types.LatestSigner(genesis.Config),
+	apiBackend := &engineApiBackend{
+		BlockChain: chain,
+		db:         db,
+		genesis:    genesis,
 	}
-	// register the custom engine API, so we can serve engine requests while having more control
-	// over sequencing of individual txs.
-	n.RegisterAPIs([]rpc.API{
-		{
-			Namespace:     "engine",
-			Service:       (*L2EngineAPI)(eng),
-			Authenticated: true,
-		},
-	})
-	require.NoError(t, n.Start(), "failed to start L2 op-geth node")
+	return n, backend, apiBackend
+}
 
-	return eng
+type engineApiBackend struct {
+	*core.BlockChain
+	db      ethdb.Database
+	genesis *core.Genesis
+}
+
+func (e *engineApiBackend) Database() ethdb.Database {
+	return e.db
+}
+
+func (e *engineApiBackend) Genesis() *core.Genesis {
+	return e.genesis
 }
 
 func (s *L2Engine) EthClient() *ethclient.Client {
@@ -158,39 +171,25 @@ func (e *L2Engine) ActL2RPCFail(t Testing) {
 // ActL2IncludeTx includes the next transaction from the given address in the block that is being built
 func (e *L2Engine) ActL2IncludeTx(from common.Address) Action {
 	return func(t Testing) {
-		if e.l2BuildingHeader == nil {
-			t.InvalidAction("not currently building a block, cannot include tx from queue")
-			return
-		}
-		if e.l2ForceEmpty {
+		if e.engineApi.ForcedEmpty() {
 			e.log.Info("Skipping including a transaction because e.L2ForceEmpty is true")
-			// t.InvalidAction("cannot include any sequencer txs")
 			return
 		}
 
-		i := e.pendingIndices[from]
+		i := e.engineApi.PendingIndices(from)
 		txs, q := e.eth.TxPool().ContentFrom(from)
 		if uint64(len(txs)) <= i {
 			t.Fatalf("no pending txs from %s, and have %d unprocessable queued txs from this account", from, len(q))
 		}
 		tx := txs[i]
-		if tx.Gas() > e.l2BuildingHeader.GasLimit {
-			t.Fatalf("tx consumes %d gas, more than available in L2 block %d", tx.Gas(), e.l2BuildingHeader.GasLimit)
-		}
-		if tx.Gas() > uint64(*e.l2GasPool) {
-			t.InvalidAction("action takes too much gas: %d, only have %d", tx.Gas(), uint64(*e.l2GasPool))
-			return
-		}
-		e.pendingIndices[from] = i + 1 // won't retry the tx
-		e.l2BuildingState.SetTxContext(tx.Hash(), len(e.l2Transactions))
-		receipt, err := core.ApplyTransaction(e.l2Cfg.Config, e.l2Chain, &e.l2BuildingHeader.Coinbase,
-			e.l2GasPool, e.l2BuildingState, e.l2BuildingHeader, tx, &e.l2BuildingHeader.GasUsed, *e.l2Chain.GetVMConfig())
-		if err != nil {
-			e.l2TxFailed = append(e.l2TxFailed, tx)
-			t.Fatalf("failed to apply transaction to L2 block (tx %d): %v", len(e.l2Transactions), err)
+		err := e.engineApi.IncludeTx(tx, from)
+		if errors.Is(err, engineapi.ErrNotBuildingBlock) {
+			t.InvalidAction(err.Error())
+		} else if errors.Is(err, engineapi.ErrUsesTooMuchGas) {
+			t.InvalidAction("included tx uses too much gas: %v", err)
+		} else if err != nil {
+			t.Fatalf("include tx: %v", err)
 		}
-		e.l2Receipts = append(e.l2Receipts, receipt)
-		e.l2Transactions = append(e.l2Transactions, tx)
 	}
 }
 

op-e2e/actions/l2_engine_test.go

@@ -4,6 +4,8 @@ import (
 	"math/big"
 	"testing"
 
+	"github.com/ethereum-optimism/optimism/op-program/l2/engineapi"
+	"github.com/ethereum-optimism/optimism/op-program/l2/engineapi/test"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus/beacon"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
@@ -187,3 +189,15 @@ func TestL2EngineAPIFail(gt *testing.T) {
 	require.NoError(t, err)
 	require.Equal(gt, sd.L2Cfg.ToBlock().Hash(), head.Hash(), "expecting engine to start at genesis")
 }
+
+func TestEngineAPITests(t *testing.T) {
+	test.RunEngineAPITests(t, func() engineapi.EngineBackend {
+		jwtPath := e2eutils.WriteDefaultJWT(t)
+		dp := e2eutils.MakeDeployParams(t, defaultRollupTestParams)
+		sd := e2eutils.Setup(t, dp, defaultAlloc)
+		n, _, apiBackend := newBackend(t, sd.L2Cfg, jwtPath, nil)
+		err := n.Start()
+		require.NoError(t, err)
+		return apiBackend
+	})
+}

op-e2e/actions/l2_sequencer_test.go

@@ -98,7 +98,7 @@ func TestL2Sequencer_SequencerDrift(gt *testing.T) {
 	// We passed the sequencer drift: we can still keep the old origin, but can't include any txs
 	sequencer.ActL2KeepL1Origin(t)
 	sequencer.ActL2StartBlock(t)
-	require.True(t, engine.l2ForceEmpty, "engine should not be allowed to include anything after sequencer drift is surpassed")
+	require.True(t, engine.engineApi.ForcedEmpty(), "engine should not be allowed to include anything after sequencer drift is surpassed")
 }
 
 // TestL2Sequencer_SequencerOnlyReorg regression-tests a Goerli halt where the sequencer

op-e2e/actions/l2_engine_api.go → op-program/l2/engineapi/l2_engine_api.go

-package actions
+package engineapi
 
 import (
 	"context"
@@ -11,26 +11,74 @@ import (
 
 	"github.com/ethereum/go-ethereum/beacon/engine"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"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/types"
+	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/trie"
 
 	"github.com/ethereum-optimism/optimism/op-node/eth"
 )
 
+type EngineBackend interface {
+	CurrentBlock() *types.Header
+	CurrentSafeBlock() *types.Header
+	CurrentFinalBlock() *types.Header
+	GetHeaderByHash(hash common.Hash) *types.Header
+	GetBlockByHash(hash common.Hash) *types.Block
+	GetBlock(hash common.Hash, number uint64) *types.Block
+	// GetHeader returns the header corresponding to the hash/number argument pair.
+	GetHeader(common.Hash, uint64) *types.Header
+	HasBlockAndState(hash common.Hash, number uint64) bool
+	GetCanonicalHash(n uint64) common.Hash
+
+	GetVMConfig() *vm.Config
+	Config() *params.ChainConfig
+	// Engine retrieves the chain's consensus engine.
+	Engine() consensus.Engine
+
+	StateAt(root common.Hash) (*state.StateDB, error)
+
+	InsertBlockWithoutSetHead(block *types.Block) error
+	SetCanonical(head *types.Block) (common.Hash, error)
+	SetFinalized(header *types.Header)
+	SetSafe(header *types.Header)
+}
+
 // L2EngineAPI wraps an engine actor, and implements the RPC backend required to serve the engine API.
 // This re-implements some of the Geth API work, but changes the API backend so we can deterministically
 // build and control the L2 block contents to reach very specific edge cases as desired for testing.
-type L2EngineAPI L2Engine
+type L2EngineAPI struct {
+	log     log.Logger
+	backend EngineBackend
+
+	// L2 block building data
+	l2BuildingHeader *types.Header             // block header that we add txs to for block building
+	l2BuildingState  *state.StateDB            // state used for block building
+	l2GasPool        *core.GasPool             // track gas used of ongoing building
+	pendingIndices   map[common.Address]uint64 // per account, how many txs from the pool were already included in the block, since the pool is lagging behind block mining.
+	l2Transactions   []*types.Transaction      // collects txs that were successfully included into current block build
+	l2Receipts       []*types.Receipt          // collect receipts of ongoing building
+	l2ForceEmpty     bool                      // when no additional txs may be processed (i.e. when sequencer drift runs out)
+	l2TxFailed       []*types.Transaction      // log of failed transactions which could not be included
+
+	payloadID engine.PayloadID // ID of payload that is currently being built
+}
+
+func NewL2EngineAPI(log log.Logger, backend EngineBackend) *L2EngineAPI {
+	return &L2EngineAPI{
+		log:     log,
+		backend: backend,
+	}
+}
 
 var (
 	STATUS_INVALID = &eth.ForkchoiceUpdatedResult{PayloadStatus: eth.PayloadStatusV1{Status: eth.ExecutionInvalid}, PayloadID: nil}
 	STATUS_SYNCING = &eth.ForkchoiceUpdatedResult{PayloadStatus: eth.PayloadStatusV1{Status: eth.ExecutionSyncing}, PayloadID: nil}
-	INVALID_TERMINAL_BLOCK = eth.PayloadStatusV1{Status: eth.ExecutionInvalid, LatestValidHash: &common.Hash{}}
 )
 
 // computePayloadId computes a pseudo-random payloadid, based on the parameters.
@@ -53,16 +101,64 @@ func computePayloadId(headBlockHash common.Hash, params *eth.PayloadAttributes)
 	return out
 }
 
+func (ea *L2EngineAPI) RemainingBlockGas() uint64 {
+	return ea.l2GasPool.Gas()
+}
+
+func (ea *L2EngineAPI) ForcedEmpty() bool {
+	return ea.l2ForceEmpty
+}
+
+func (ea *L2EngineAPI) PendingIndices(from common.Address) uint64 {
+	return ea.pendingIndices[from]
+}
+
+var (
+	ErrNotBuildingBlock = errors.New("not currently building a block, cannot include tx from queue")
+	ErrExceedsGasLimit  = errors.New("tx gas exceeds block gas limit")
+	ErrUsesTooMuchGas   = errors.New("action takes too much gas")
+)
+
+func (ea *L2EngineAPI) IncludeTx(tx *types.Transaction, from common.Address) error {
+	if ea.l2BuildingHeader == nil {
+		return ErrNotBuildingBlock
+	}
+	if ea.l2ForceEmpty {
+		ea.log.Info("Skipping including a transaction because e.L2ForceEmpty is true")
+		// t.InvalidAction("cannot include any sequencer txs")
+		return nil
+	}
+
+	if tx.Gas() > ea.l2BuildingHeader.GasLimit {
+		return fmt.Errorf("%w tx gas: %d, block gas limit: %d", ErrExceedsGasLimit, tx.Gas(), ea.l2BuildingHeader.GasLimit)
+	}
+	if tx.Gas() > uint64(*ea.l2GasPool) {
+		return fmt.Errorf("%w: %d, only have %d", ErrUsesTooMuchGas, tx.Gas(), uint64(*ea.l2GasPool))
+	}
+
+	ea.pendingIndices[from] = ea.pendingIndices[from] + 1 // won't retry the tx
+	ea.l2BuildingState.SetTxContext(tx.Hash(), len(ea.l2Transactions))
+	receipt, err := core.ApplyTransaction(ea.backend.Config(), ea.backend, &ea.l2BuildingHeader.Coinbase,
+		ea.l2GasPool, ea.l2BuildingState, ea.l2BuildingHeader, tx, &ea.l2BuildingHeader.GasUsed, *ea.backend.GetVMConfig())
+	if err != nil {
+		ea.l2TxFailed = append(ea.l2TxFailed, tx)
+		return fmt.Errorf("invalid L2 block (tx %d): %w", len(ea.l2Transactions), err)
+	}
+	ea.l2Receipts = append(ea.l2Receipts, receipt)
+	ea.l2Transactions = append(ea.l2Transactions, tx)
+	return nil
+}
+
 func (ea *L2EngineAPI) startBlock(parent common.Hash, params *eth.PayloadAttributes) error {
 	if ea.l2BuildingHeader != nil {
 		ea.log.Warn("started building new block without ending previous block", "previous", ea.l2BuildingHeader, "prev_payload_id", ea.payloadID)
 	}
 
-	parentHeader := ea.l2Chain.GetHeaderByHash(parent)
+	parentHeader := ea.backend.GetHeaderByHash(parent)
 	if parentHeader == nil {
 		return fmt.Errorf("uknown parent block: %s", parent)
 	}
-	statedb, err := state.New(parentHeader.Root, state.NewDatabase(ea.l2Database), nil)
+	statedb, err := ea.backend.StateAt(parentHeader.Root)
 	if err != nil {
 		return fmt.Errorf("failed to init state db around block %s (state %s): %w", parent, parentHeader.Root, err)
 	}
@@ -78,7 +174,7 @@ func (ea *L2EngineAPI) startBlock(parent common.Hash, params *eth.PayloadAttribu
 		MixDigest:  common.Hash(params.PrevRandao),
 	}
 
-	header.BaseFee = misc.CalcBaseFee(ea.l2Cfg.Config, parentHeader)
+	header.BaseFee = misc.CalcBaseFee(ea.backend.Config(), parentHeader)
 
 	ea.l2BuildingHeader = header
 	ea.l2BuildingState = statedb
@@ -96,8 +192,8 @@ func (ea *L2EngineAPI) startBlock(parent common.Hash, params *eth.PayloadAttribu
 			return fmt.Errorf("transaction %d is not valid: %w", i, err)
 		}
 		ea.l2BuildingState.SetTxContext(tx.Hash(), i)
-		receipt, err := core.ApplyTransaction(ea.l2Cfg.Config, ea.l2Chain, &ea.l2BuildingHeader.Coinbase,
-			ea.l2GasPool, ea.l2BuildingState, ea.l2BuildingHeader, &tx, &ea.l2BuildingHeader.GasUsed, *ea.l2Chain.GetVMConfig())
+		receipt, err := core.ApplyTransaction(ea.backend.Config(), ea.backend, &ea.l2BuildingHeader.Coinbase,
+			ea.l2GasPool, ea.l2BuildingState, ea.l2BuildingHeader, &tx, &ea.l2BuildingHeader.GasUsed, *ea.backend.GetVMConfig())
 		if err != nil {
 			ea.l2TxFailed = append(ea.l2TxFailed, &tx)
 			return fmt.Errorf("failed to apply deposit transaction to L2 block (tx %d): %w", i, err)
@@ -116,17 +212,8 @@ func (ea *L2EngineAPI) endBlock() (*types.Block, error) {
 	ea.l2BuildingHeader = nil
 
 	header.GasUsed = header.GasLimit - uint64(*ea.l2GasPool)
-	header.Root = ea.l2BuildingState.IntermediateRoot(ea.l2Cfg.Config.IsEIP158(header.Number))
+	header.Root = ea.l2BuildingState.IntermediateRoot(ea.backend.Config().IsEIP158(header.Number))
 	block := types.NewBlock(header, ea.l2Transactions, nil, ea.l2Receipts, trie.NewStackTrie(nil))
-
-	// Write state changes to db
-	root, err := ea.l2BuildingState.Commit(ea.l2Cfg.Config.IsEIP158(header.Number))
-	if err != nil {
-		return nil, fmt.Errorf("l2 state write error: %w", err)
-	}
-	if err := ea.l2BuildingState.Database().TrieDB().Commit(root, false); err != nil {
-		return nil, fmt.Errorf("l2 trie write error: %w", err)
-	}
 	return block, nil
 }
 
@@ -153,31 +240,16 @@ func (ea *L2EngineAPI) ForkchoiceUpdatedV1(ctx context.Context, state *eth.Forkc
 	// Check whether we have the block yet in our database or not. If not, we'll
 	// need to either trigger a sync, or to reject this forkchoice update for a
 	// reason.
-	block := ea.l2Chain.GetBlockByHash(state.HeadBlockHash)
+	block := ea.backend.GetBlockByHash(state.HeadBlockHash)
 	if block == nil {
 		// TODO: syncing not supported yet
 		return STATUS_SYNCING, nil
 	}
 	// Block is known locally, just sanity check that the beacon client does not
 	// attempt to push us back to before the merge.
-	if block.Difficulty().BitLen() > 0 || block.NumberU64() == 0 {
-		var (
-			td  = ea.l2Chain.GetTd(state.HeadBlockHash, block.NumberU64())
-			ptd = ea.l2Chain.GetTd(block.ParentHash(), block.NumberU64()-1)
-			ttd = ea.l2Chain.Config().TerminalTotalDifficulty
-		)
-		if td == nil || (block.NumberU64() > 0 && ptd == nil) {
-			ea.log.Error("TDs unavailable for TTD check", "number", block.NumberU64(), "hash", state.HeadBlockHash, "td", td, "parent", block.ParentHash(), "ptd", ptd)
-			return STATUS_INVALID, errors.New("TDs unavailable for TDD check")
-		}
-		if td.Cmp(ttd) < 0 {
-			ea.log.Error("Refusing beacon update to pre-merge", "number", block.NumberU64(), "hash", state.HeadBlockHash, "diff", block.Difficulty(), "age", common.PrettyAge(time.Unix(int64(block.Time()), 0)))
-			return &eth.ForkchoiceUpdatedResult{PayloadStatus: INVALID_TERMINAL_BLOCK, PayloadID: nil}, nil
-		}
-		if block.NumberU64() > 0 && ptd.Cmp(ttd) >= 0 {
-			ea.log.Error("Parent block is already post-ttd", "number", block.NumberU64(), "hash", state.HeadBlockHash, "diff", block.Difficulty(), "age", common.PrettyAge(time.Unix(int64(block.Time()), 0)))
-			return &eth.ForkchoiceUpdatedResult{PayloadStatus: INVALID_TERMINAL_BLOCK, PayloadID: nil}, nil
-		}
+	// Note: Differs from op-geth implementation as pre-merge blocks are never supported here
+	if block.Difficulty().BitLen() > 0 {
+		return STATUS_INVALID, errors.New("pre-merge blocks not supported")
 	}
 	valid := func(id *engine.PayloadID) *eth.ForkchoiceUpdatedResult {
 		return &eth.ForkchoiceUpdatedResult{
@@ -185,16 +257,16 @@ func (ea *L2EngineAPI) ForkchoiceUpdatedV1(ctx context.Context, state *eth.Forkc
 			PayloadID:     id,
 		}
 	}
-	if rawdb.ReadCanonicalHash(ea.l2Database, block.NumberU64()) != state.HeadBlockHash {
+	if ea.backend.GetCanonicalHash(block.NumberU64()) != state.HeadBlockHash {
 		// Block is not canonical, set head.
-		if latestValid, err := ea.l2Chain.SetCanonical(block); err != nil {
+		if latestValid, err := ea.backend.SetCanonical(block); err != nil {
 			return &eth.ForkchoiceUpdatedResult{PayloadStatus: eth.PayloadStatusV1{Status: eth.ExecutionInvalid, LatestValidHash: &latestValid}}, err
 		}
-	} else if ea.l2Chain.CurrentBlock().Hash() == state.HeadBlockHash {
+	} else if ea.backend.CurrentBlock().Hash() == state.HeadBlockHash {
 		// If the specified head matches with our local head, do nothing and keep
 		// generating the payload. It's a special corner case that a few slots are
 		// missing and we are requested to generate the payload in slot.
-	} else if ea.l2Chain.Config().Optimism == nil { // minor L2Engine API divergence: allow proposers to reorg their own chain
+	} else if ea.backend.Config().Optimism == nil { // minor L2Engine API divergence: allow proposers to reorg their own chain
 		panic("engine not configured as optimism engine")
 	}
 
@@ -202,30 +274,30 @@ func (ea *L2EngineAPI) ForkchoiceUpdatedV1(ctx context.Context, state *eth.Forkc
 	// chain final and completely in PoS mode.
 	if state.FinalizedBlockHash != (common.Hash{}) {
 		// If the finalized block is not in our canonical tree, somethings wrong
-		finalHeader := ea.l2Chain.GetHeaderByHash(state.FinalizedBlockHash)
+		finalHeader := ea.backend.GetHeaderByHash(state.FinalizedBlockHash)
 		if finalHeader == nil {
 			ea.log.Warn("Final block not available in database", "hash", state.FinalizedBlockHash)
 			return STATUS_INVALID, engine.InvalidForkChoiceState.With(errors.New("final block not available in database"))
-		} else if rawdb.ReadCanonicalHash(ea.l2Database, finalHeader.Number.Uint64()) != state.FinalizedBlockHash {
+		} else if ea.backend.GetCanonicalHash(finalHeader.Number.Uint64()) != state.FinalizedBlockHash {
 			ea.log.Warn("Final block not in canonical chain", "number", block.NumberU64(), "hash", state.HeadBlockHash)
 			return STATUS_INVALID, engine.InvalidForkChoiceState.With(errors.New("final block not in canonical chain"))
 		}
 		// Set the finalized block
-		ea.l2Chain.SetFinalized(finalHeader)
+		ea.backend.SetFinalized(finalHeader)
 	}
 	// Check if the safe block hash is in our canonical tree, if not somethings wrong
 	if state.SafeBlockHash != (common.Hash{}) {
-		safeHeader := ea.l2Chain.GetHeaderByHash(state.SafeBlockHash)
+		safeHeader := ea.backend.GetHeaderByHash(state.SafeBlockHash)
 		if safeHeader == nil {
 			ea.log.Warn("Safe block not available in database")
 			return STATUS_INVALID, engine.InvalidForkChoiceState.With(errors.New("safe block not available in database"))
 		}
-		if rawdb.ReadCanonicalHash(ea.l2Database, safeHeader.Number.Uint64()) != state.SafeBlockHash {
+		if ea.backend.GetCanonicalHash(safeHeader.Number.Uint64()) != state.SafeBlockHash {
 			ea.log.Warn("Safe block not in canonical chain")
 			return STATUS_INVALID, engine.InvalidForkChoiceState.With(errors.New("safe block not in canonical chain"))
 		}
 		// Set the safe block
-		ea.l2Chain.SetSafe(safeHeader)
+		ea.backend.SetSafe(safeHeader)
 	}
 	// If payload generation was requested, create a new block to be potentially
 	// sealed by the beacon client. The payload will be requested later, and we
@@ -270,7 +342,7 @@ func (ea *L2EngineAPI) NewPayloadV1(ctx context.Context, payload *eth.ExecutionP
 	}
 	// If we already have the block locally, ignore the entire execution and just
 	// return a fake success.
-	if block := ea.l2Chain.GetBlockByHash(payload.BlockHash); block != nil {
+	if block := ea.backend.GetBlockByHash(payload.BlockHash); block != nil {
 		ea.log.Warn("Ignoring already known beacon payload", "number", payload.BlockNumber, "hash", payload.BlockHash, "age", common.PrettyAge(time.Unix(int64(block.Time()), 0)))
 		hash := block.Hash()
 		return &eth.PayloadStatusV1{Status: eth.ExecutionValid, LatestValidHash: &hash}, nil
@@ -278,16 +350,23 @@ func (ea *L2EngineAPI) NewPayloadV1(ctx context.Context, payload *eth.ExecutionP
 
 	// TODO: skipping invalid ancestor check (i.e. not remembering previously failed blocks)
 
-	parent := ea.l2Chain.GetBlock(block.ParentHash(), block.NumberU64()-1)
+	parent := ea.backend.GetBlock(block.ParentHash(), block.NumberU64()-1)
 	if parent == nil {
 		// TODO: hack, saying we accepted if we don't know the parent block. Might want to return critical error if we can't actually sync.
 		return &eth.PayloadStatusV1{Status: eth.ExecutionAccepted, LatestValidHash: nil}, nil
 	}
-	if !ea.l2Chain.HasBlockAndState(block.ParentHash(), block.NumberU64()-1) {
+
+	if block.Time() <= parent.Time() {
+		log.Warn("Invalid timestamp", "parent", block.Time(), "block", block.Time())
+		return ea.invalid(errors.New("invalid timestamp"), parent.Header()), nil
+	}
+
+	if !ea.backend.HasBlockAndState(block.ParentHash(), block.NumberU64()-1) {
 		ea.log.Warn("State not available, ignoring new payload")
 		return &eth.PayloadStatusV1{Status: eth.ExecutionAccepted}, nil
 	}
-	if err := ea.l2Chain.InsertBlockWithoutSetHead(block); err != nil {
+	log.Trace("Inserting block without sethead", "hash", block.Hash(), "number", block.Number)
+	if err := ea.backend.InsertBlockWithoutSetHead(block); err != nil {
 		ea.log.Warn("NewPayloadV1: inserting block failed", "error", err)
 		// TODO not remembering the payload as invalid
 		return ea.invalid(err, parent.Header()), nil
@@ -297,7 +376,7 @@ func (ea *L2EngineAPI) NewPayloadV1(ctx context.Context, payload *eth.ExecutionP
 }
 
 func (ea *L2EngineAPI) invalid(err error, latestValid *types.Header) *eth.PayloadStatusV1 {
-	currentHash := ea.l2Chain.CurrentBlock().Hash()
+	currentHash := ea.backend.CurrentBlock().Hash()
 	if latestValid != nil {
 		// Set latest valid hash to 0x0 if parent is PoW block
 		currentHash = common.Hash{}

op-program/l2/engineapi/test/l2_engine_api_tests.go

+package test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/ethereum-optimism/optimism/op-node/eth"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+	"github.com/ethereum-optimism/optimism/op-node/testlog"
+	"github.com/ethereum-optimism/optimism/op-program/l2/engineapi"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/stretchr/testify/require"
+)
+
+var gasLimit = eth.Uint64Quantity(30_000_000)
+var feeRecipient = common.Address{}
+
+func RunEngineAPITests(t *testing.T, createBackend func() engineapi.EngineBackend) {
+	t.Run("CreateBlock", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+
+		block := api.addBlock()
+		api.assert.Equal(block.BlockHash, api.headHash(), "should create and import new block")
+	})
+
+	t.Run("IncludeRequiredTransactions", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		txData, err := derive.L1InfoDeposit(1, eth.HeaderBlockInfo(genesis), eth.SystemConfig{}, true)
+		api.assert.NoError(err)
+		tx := types.NewTx(txData)
+		block := api.addBlock(tx)
+		api.assert.Equal(block.BlockHash, api.headHash(), "should create and import new block")
+		imported := api.backend.GetBlockByHash(block.BlockHash)
+		api.assert.Len(imported.Transactions(), 1, "should include transaction")
+	})
+
+	t.Run("IgnoreUpdateHeadToOlderBlock", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesisHash := api.headHash()
+		api.addBlock()
+		block := api.addBlock()
+		api.assert.Equal(block.BlockHash, api.headHash(), "should have extended chain")
+
+		api.forkChoiceUpdated(genesisHash, genesisHash, genesisHash)
+		api.assert.Equal(block.BlockHash, api.headHash(), "should not have reset chain head")
+	})
+
+	t.Run("AllowBuildingOnOlderBlock", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+		api.addBlock()
+		block := api.addBlock()
+		api.assert.Equal(block.BlockHash, api.headHash(), "should have extended chain")
+
+		payloadID := api.startBlockBuilding(genesis, eth.Uint64Quantity(genesis.Time+3))
+		api.assert.Equal(block.BlockHash, api.headHash(), "should not reset chain head when building starts")
+
+		payload := api.getPayload(payloadID)
+		api.assert.Equal(genesis.Hash(), payload.ParentHash, "should have old block as parent")
+
+		api.newPayload(payload)
+		api.forkChoiceUpdated(payload.BlockHash, genesis.Hash(), genesis.Hash())
+		api.assert.Equal(payload.BlockHash, api.headHash(), "should reorg to block built on old parent")
+	})
+
+	t.Run("RejectInvalidBlockHash", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+
+		// Invalid because BlockHash won't be correct (among many other reasons)
+		block := &eth.ExecutionPayload{}
+		r, err := api.engine.NewPayloadV1(api.ctx, block)
+		api.assert.NoError(err)
+		api.assert.Equal(eth.ExecutionInvalidBlockHash, r.Status)
+	})
+
+	t.Run("RejectBlockWithInvalidStateTransition", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		// Build a valid block
+		payloadID := api.startBlockBuilding(genesis, eth.Uint64Quantity(genesis.Time+2))
+		newBlock := api.getPayload(payloadID)
+
+		// But then make it invalid by changing the state root
+		newBlock.StateRoot = eth.Bytes32(genesis.TxHash)
+		updateBlockHash(newBlock)
+
+		r, err := api.engine.NewPayloadV1(api.ctx, newBlock)
+		api.assert.NoError(err)
+		api.assert.Equal(eth.ExecutionInvalid, r.Status)
+	})
+
+	t.Run("RejectBlockWithSameTimeAsParent", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		payloadID := api.startBlockBuilding(genesis, eth.Uint64Quantity(genesis.Time))
+		newBlock := api.getPayload(payloadID)
+
+		r, err := api.engine.NewPayloadV1(api.ctx, newBlock)
+		api.assert.NoError(err)
+		api.assert.Equal(eth.ExecutionInvalid, r.Status)
+	})
+
+	t.Run("RejectBlockWithTimeBeforeParent", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		payloadID := api.startBlockBuilding(genesis, eth.Uint64Quantity(genesis.Time-1))
+		newBlock := api.getPayload(payloadID)
+
+		r, err := api.engine.NewPayloadV1(api.ctx, newBlock)
+		api.assert.NoError(err)
+		api.assert.Equal(eth.ExecutionInvalid, r.Status)
+	})
+
+	t.Run("UpdateSafeAndFinalizedHead", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+
+		finalized := api.addBlock()
+		safe := api.addBlock()
+		head := api.addBlock()
+
+		api.forkChoiceUpdated(head.BlockHash, safe.BlockHash, finalized.BlockHash)
+		api.assert.Equal(head.BlockHash, api.headHash(), "should update head block")
+		api.assert.Equal(safe.BlockHash, api.safeHash(), "should update safe block")
+		api.assert.Equal(finalized.BlockHash, api.finalHash(), "should update finalized block")
+	})
+
+	t.Run("RejectSafeHeadWhenNotAncestor", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		api.addBlock()
+		chainA2 := api.addBlock()
+		chainA3 := api.addBlock()
+
+		chainB1 := api.addBlockWithParent(genesis, eth.Uint64Quantity(genesis.Time+3))
+
+		result, err := api.engine.ForkchoiceUpdatedV1(api.ctx, &eth.ForkchoiceState{
+			HeadBlockHash:      chainA3.BlockHash,
+			SafeBlockHash:      chainB1.BlockHash,
+			FinalizedBlockHash: chainA2.BlockHash,
+		}, nil)
+		api.assert.ErrorContains(err, "Invalid forkchoice state", "should return error from forkChoiceUpdated")
+		api.assert.Equal(eth.ExecutionInvalid, result.PayloadStatus.Status, "forkChoiceUpdated should return invalid")
+		api.assert.Nil(result.PayloadID, "should not provide payload ID when invalid")
+	})
+
+	t.Run("RejectFinalizedHeadWhenNotAncestor", func(t *testing.T) {
+		api := newTestHelper(t, createBackend)
+		genesis := api.backend.CurrentBlock()
+
+		api.addBlock()
+		chainA2 := api.addBlock()
+		chainA3 := api.addBlock()
+
+		chainB1 := api.addBlockWithParent(genesis, eth.Uint64Quantity(genesis.Time+3))
+
+		result, err := api.engine.ForkchoiceUpdatedV1(api.ctx, &eth.ForkchoiceState{
+			HeadBlockHash:      chainA3.BlockHash,
+			SafeBlockHash:      chainA2.BlockHash,
+			FinalizedBlockHash: chainB1.BlockHash,
+		}, nil)
+		api.assert.ErrorContains(err, "Invalid forkchoice state", "should return error from forkChoiceUpdated")
+		api.assert.Equal(eth.ExecutionInvalid, result.PayloadStatus.Status, "forkChoiceUpdated should return invalid")
+		api.assert.Nil(result.PayloadID, "should not provide payload ID when invalid")
+	})
+}
+
+// Updates the block hash to the expected value based on the other fields in the payload
+func updateBlockHash(newBlock *eth.ExecutionPayload) {
+	// And fix up the block hash
+	newHash, _ := newBlock.CheckBlockHash()
+	newBlock.BlockHash = newHash
+}
+
+type testHelper struct {
+	t       *testing.T
+	ctx     context.Context
+	engine  *engineapi.L2EngineAPI
+	backend engineapi.EngineBackend
+	assert  *require.Assertions
+}
+
+func newTestHelper(t *testing.T, createBackend func() engineapi.EngineBackend) *testHelper {
+	logger := testlog.Logger(t, log.LvlDebug)
+	ctx := context.Background()
+	backend := createBackend()
+	api := engineapi.NewL2EngineAPI(logger, backend)
+	test := &testHelper{
+		t:       t,
+		ctx:     ctx,
+		engine:  api,
+		backend: backend,
+		assert:  require.New(t),
+	}
+	return test
+}
+
+func (h *testHelper) headHash() common.Hash {
+	return h.backend.CurrentBlock().Hash()
+}
+
+func (h *testHelper) safeHash() common.Hash {
+	return h.backend.CurrentSafeBlock().Hash()
+}
+
+func (h *testHelper) finalHash() common.Hash {
+	return h.backend.CurrentFinalBlock().Hash()
+}
+
+func (h *testHelper) Log(args ...any) {
+	h.t.Log(args...)
+}
+
+func (h *testHelper) addBlock(txs ...*types.Transaction) *eth.ExecutionPayload {
+	head := h.backend.CurrentBlock()
+	return h.addBlockWithParent(head, eth.Uint64Quantity(head.Time+2), txs...)
+}
+
+func (h *testHelper) addBlockWithParent(head *types.Header, timestamp eth.Uint64Quantity, txs ...*types.Transaction) *eth.ExecutionPayload {
+	prevHead := h.backend.CurrentBlock()
+	id := h.startBlockBuilding(head, timestamp, txs...)
+
+	block := h.getPayload(id)
+	h.assert.Equal(timestamp, block.Timestamp, "should create block with correct timestamp")
+	h.assert.Equal(head.Hash(), block.ParentHash, "should have correct parent")
+	h.assert.Len(block.Transactions, len(txs))
+
+	h.newPayload(block)
+
+	// Should not have changed the chain head yet
+	h.assert.Equal(prevHead, h.backend.CurrentBlock())
+
+	h.forkChoiceUpdated(block.BlockHash, head.Hash(), head.Hash())
+	h.assert.Equal(block.BlockHash, h.backend.CurrentBlock().Hash())
+	return block
+}
+
+func (h *testHelper) forkChoiceUpdated(head common.Hash, safe common.Hash, finalized common.Hash) {
+	h.Log("forkChoiceUpdated", "head", head, "safe", safe, "finalized", finalized)
+	result, err := h.engine.ForkchoiceUpdatedV1(h.ctx, &eth.ForkchoiceState{
+		HeadBlockHash:      head,
+		SafeBlockHash:      safe,
+		FinalizedBlockHash: finalized,
+	}, nil)
+	h.assert.NoError(err)
+	h.assert.Equal(eth.ExecutionValid, result.PayloadStatus.Status, "forkChoiceUpdated should return valid")
+	h.assert.Nil(result.PayloadStatus.ValidationError, "should not have validation error when valid")
+	h.assert.Nil(result.PayloadID, "should not provide payload ID when block building not requested")
+}
+
+func (h *testHelper) startBlockBuilding(head *types.Header, newBlockTimestamp eth.Uint64Quantity, txs ...*types.Transaction) *eth.PayloadID {
+	h.Log("Start block building", "head", head.Hash(), "timestamp", newBlockTimestamp)
+	var txData []eth.Data
+	for _, tx := range txs {
+		rlp, err := tx.MarshalBinary()
+		h.assert.NoError(err, "Failed to marshall tx %v", tx)
+		txData = append(txData, rlp)
+	}
+	result, err := h.engine.ForkchoiceUpdatedV1(h.ctx, &eth.ForkchoiceState{
+		HeadBlockHash:      head.Hash(),
+		SafeBlockHash:      head.Hash(),
+		FinalizedBlockHash: head.Hash(),
+	}, &eth.PayloadAttributes{
+		Timestamp:             newBlockTimestamp,
+		PrevRandao:            eth.Bytes32(head.MixDigest),
+		SuggestedFeeRecipient: feeRecipient,
+		Transactions:          txData,
+		NoTxPool:              true,
+		GasLimit:              &gasLimit,
+	})
+	h.assert.NoError(err)
+	h.assert.Equal(eth.ExecutionValid, result.PayloadStatus.Status)
+	id := result.PayloadID
+	h.assert.NotNil(id)
+	return id
+}
+
+func (h *testHelper) getPayload(id *eth.PayloadID) *eth.ExecutionPayload {
+	h.Log("getPayload", "id", id)
+	block, err := h.engine.GetPayloadV1(h.ctx, *id)
+	h.assert.NoError(err)
+	h.assert.NotNil(block)
+	return block
+}
+
+func (h *testHelper) newPayload(block *eth.ExecutionPayload) {
+	h.Log("newPayload", "hash", block.BlockHash)
+	r, err := h.engine.NewPayloadV1(h.ctx, block)
+	h.assert.NoError(err)
+	h.assert.Equal(eth.ExecutionValid, r.Status)
+	h.assert.Nil(r.ValidationError)
+}