Merge pull request #5120 from ethereum-optimism/fix/allow-deposit-only-legacy-batches

batch-submitter: allow deposit only batches

.changeset/fresh-pots-move.md

+---
+'@eth-optimism/batch-submitter-service': patch
+---
+
+Allow deposit only batches

batch-submitter/drivers/sequencer/batch_test.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/ethereum-optimism/optimism/batch-submitter/drivers/sequencer"
 	l2common "github.com/ethereum-optimism/optimism/l2geth/common"
+	"github.com/ethereum-optimism/optimism/l2geth/core/types"
 	l2types "github.com/ethereum-optimism/optimism/l2geth/core/types"
 	"github.com/stretchr/testify/require"
 )
@@ -47,3 +48,76 @@ func TestBatchElementFromBlock(t *testing.T) {
 	require.False(t, element.IsSequencerTx())
 	require.Nil(t, element.Tx)
 }
+
+func TestGenSequencerParams(t *testing.T) {
+	tx := types.NewTransaction(0, l2common.Address{}, big.NewInt(0), 0, big.NewInt(0), []byte{})
+
+	shouldStartAtElement := uint64(1)
+	blockOffset := uint64(1)
+	batches := []sequencer.BatchElement{
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 1, BlockNumber: 1, Tx: sequencer.NewCachedTx(tx)},
+	}
+
+	params, err := sequencer.GenSequencerBatchParams(shouldStartAtElement, blockOffset, batches)
+	require.NoError(t, err)
+
+	require.Equal(t, uint64(0), params.ShouldStartAtElement)
+	require.Equal(t, uint64(len(batches)), params.TotalElementsToAppend)
+	require.Equal(t, len(batches), len(params.Contexts))
+	// There is only 1 sequencer tx
+	require.Equal(t, 1, len(params.Txs))
+
+	// There are 2 contexts
+	// The first context contains the deposit
+	context1 := params.Contexts[0]
+	require.Equal(t, uint64(0), context1.NumSequencedTxs)
+	require.Equal(t, uint64(1), context1.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context1.Timestamp)
+	require.Equal(t, uint64(1), context1.BlockNumber)
+
+	// The second context contains the sequencer tx
+	context2 := params.Contexts[1]
+	require.Equal(t, uint64(1), context2.NumSequencedTxs)
+	require.Equal(t, uint64(0), context2.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context2.Timestamp)
+	require.Equal(t, uint64(1), context2.BlockNumber)
+}
+
+func TestGenSequencerParamsOnlyDeposits(t *testing.T) {
+	shouldStartAtElement := uint64(1)
+	blockOffset := uint64(1)
+	batches := []sequencer.BatchElement{
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 1, BlockNumber: 1},
+		{Timestamp: 2, BlockNumber: 2},
+	}
+
+	params, err := sequencer.GenSequencerBatchParams(shouldStartAtElement, blockOffset, batches)
+	require.NoError(t, err)
+
+	// The batches will pack deposits into the same context when their
+	// timestamps and blocknumbers are the same
+	require.Equal(t, uint64(0), params.ShouldStartAtElement)
+	require.Equal(t, uint64(len(batches)), params.TotalElementsToAppend)
+	// 2 deposits have the same timestamp + blocknumber, they go in the
+	// same context. 1 deposit has a different timestamp + blocknumber,
+	// it goes into a different context. Therefore there are 2 contexts
+	require.Equal(t, 2, len(params.Contexts))
+	// No sequencer txs
+	require.Equal(t, 0, len(params.Txs))
+
+	// There are 2 contexts
+	// The first context contains the deposit
+	context1 := params.Contexts[0]
+	require.Equal(t, uint64(0), context1.NumSequencedTxs)
+	require.Equal(t, uint64(2), context1.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(1), context1.Timestamp)
+	require.Equal(t, uint64(1), context1.BlockNumber)
+
+	context2 := params.Contexts[1]
+	require.Equal(t, uint64(0), context2.NumSequencedTxs)
+	require.Equal(t, uint64(1), context2.NumSubsequentQueueTxs)
+	require.Equal(t, uint64(2), context2.Timestamp)
+	require.Equal(t, uint64(2), context2.BlockNumber)
+}

batch-submitter/drivers/sequencer/encoding.go

@@ -222,11 +222,6 @@ func (p *AppendSequencerBatchParams) Write(
 		return ErrMalformedBatch
 	}
 
-	// There must be transactions if there are contexts
-	if len(p.Txs) == 0 && len(p.Contexts) != 0 {
-		return ErrMalformedBatch
-	}
-
 	// copy the contexts as to not malleate the struct
 	// when it is a typed batch
 	contexts := make([]BatchContext, 0, len(p.Contexts)+1)
@@ -361,9 +356,6 @@ func (p *AppendSequencerBatchParams) Read(r io.Reader) error {
 			if len(p.Contexts) == 0 && len(p.Txs) != 0 {
 				return ErrMalformedBatch
 			}
-			if len(p.Txs) == 0 && len(p.Contexts) != 0 {
-				return ErrMalformedBatch
-			}
 			return closeReader()
 		} else if err != nil {
 			return err

batch-submitter/drivers/sequencer/testdata/valid_append_sequencer_batch_params.json

@@ -46,7 +46,7 @@
         }
       ],
       "txs": [],
-      "error": true
+      "error": false
     },
     {
       "name": "multiple-contexts-no-txs",
@@ -80,7 +80,7 @@
         }
       ],
       "txs": [],
-      "error": true
+      "error": false
     },
     {
       "name": "complex",