Handle noTxPool correctly

op-node/rollup/clsync/clsync.go

@@ -39,6 +39,7 @@ type L1OriginSelector interface {
 type CLSync struct {
 	log               log.Logger
 	cfg               *rollup.Config
+	spec              *rollup.ChainSpec
 	metrics           Metrics
 	ec                Engine
 	n                 Network
@@ -52,6 +53,7 @@ func NewCLSync(log log.Logger, cfg *rollup.Config, metrics Metrics, ec Engine, n
 	return &CLSync{
 		log:               log,
 		cfg:               cfg,
+		spec:              rollup.NewChainSpec(cfg),
 		metrics:           metrics,
 		ec:                ec,
 		n:                 n,
@@ -162,6 +164,28 @@ func (eq *CLSync) PublishAttributes(ctx context.Context, l2head eth.L2BlockRef)
 		return fmt.Errorf("error preparing payload attributes: %w", err)
 	}
 
+	// If our next L2 block timestamp is beyond the Sequencer drift threshold, then we must produce
+	// empty blocks (other than the L1 info deposit and any user deposits). We handle this by
+	// setting NoTxPool to true, which will cause the Sequencer to not include any transactions
+	// from the transaction pool.
+	attrs.NoTxPool = uint64(attrs.Timestamp) > l1Origin.Time+eq.spec.MaxSequencerDrift(l1Origin.Time)
+
+	// For the Ecotone activation block we shouldn't include any sequencer transactions.
+	if eq.cfg.IsEcotoneActivationBlock(uint64(attrs.Timestamp)) {
+		attrs.NoTxPool = true
+		eq.log.Info("Sequencing Ecotone upgrade block")
+	}
+
+	// For the Fjord activation block we shouldn't include any sequencer transactions.
+	if eq.cfg.IsFjordActivationBlock(uint64(attrs.Timestamp)) {
+		attrs.NoTxPool = true
+		eq.log.Info("Sequencing Fjord upgrade block")
+	}
+
+	eq.log.Debug("prepared attributes for new block",
+		"num", l2head.Number+1, "time", uint64(attrs.Timestamp),
+		"origin", l1Origin, "origin_time", l1Origin.Time, "noTxPool", attrs.NoTxPool)
+
 	withParent := &derive.AttributesWithParent{
 		Attributes:   attrs,
 		Parent:       l2head,

op-node/rollup/driver/driver.go

@@ -190,6 +190,7 @@ func NewDriver(
 		sequencerActive:    make(chan chan bool, 10),
 		sequencerNotifs:    sequencerStateListener,
 		config:             cfg,
+		spec:               rollup.NewChainSpec(cfg),
 		syncCfg:            syncCfg,
 		driverConfig:       driverCfg,
 		driverCtx:          driverCtx,

op-node/rollup/driver/state.go

@@ -73,6 +73,7 @@ type Driver struct {
 
 	// Rollup config: rollup chain configuration
 	config *rollup.Config
+	spec   *rollup.ChainSpec
 
 	sequencerConductor conductor.SequencerConductor
 
@@ -493,6 +494,28 @@ func (d *Driver) PublishL2Attributes(ctx context.Context, l2head eth.L2BlockRef)
 		return err
 	}
 
+	// If our next L2 block timestamp is beyond the Sequencer drift threshold, then we must produce
+	// empty blocks (other than the L1 info deposit and any user deposits). We handle this by
+	// setting NoTxPool to true, which will cause the Sequencer to not include any transactions
+	// from the transaction pool.
+	attrs.NoTxPool = uint64(attrs.Timestamp) > l1Origin.Time+d.spec.MaxSequencerDrift(l1Origin.Time)
+
+	// For the Ecotone activation block we shouldn't include any sequencer transactions.
+	if d.config.IsEcotoneActivationBlock(uint64(attrs.Timestamp)) {
+		attrs.NoTxPool = true
+		d.log.Info("Sequencing Ecotone upgrade block")
+	}
+
+	// For the Fjord activation block we shouldn't include any sequencer transactions.
+	if d.config.IsFjordActivationBlock(uint64(attrs.Timestamp)) {
+		attrs.NoTxPool = true
+		d.log.Info("Sequencing Fjord upgrade block")
+	}
+
+	d.log.Debug("prepared attributes for new block",
+		"num", l2head.Number+1, "time", uint64(attrs.Timestamp),
+		"origin", l1Origin, "origin_time", l1Origin.Time, "noTxPool", attrs.NoTxPool)
+
 	withParent := &derive.AttributesWithParent{
 		Attributes:   attrs,
 		Parent:       l2head,