fix tracer to work by block stateroot instead of by tx

db/migrations/state/0015.sql

@@ -0,0 +1,6 @@
+-- +migrate Up
+CREATE INDEX IF NOT EXISTS idx_receipt_tx_index ON state.receipt (block_num, tx_index);
+
+-- +migrate Down
+DROP INDEX IF EXISTS state.idx_receipt_tx_index;
+

db/migrations/state/0015_test.go

@@ -0,0 +1,49 @@
+package migrations_test
+
+import (
+	"database/sql"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// this migration changes length of the token name
+type migrationTest0015 struct{}
+
+func (m migrationTest0015) InsertData(db *sql.DB) error {
+	return nil
+}
+
+func (m migrationTest0015) RunAssertsAfterMigrationUp(t *testing.T, db *sql.DB) {
+	indexes := []string{
+		"idx_receipt_tx_index",
+	}
+	// Check indexes adding
+	for _, idx := range indexes {
+		// getIndex
+		const getIndex = `SELECT count(*) FROM pg_indexes WHERE indexname = $1;`
+		row := db.QueryRow(getIndex, idx)
+		var result int
+		assert.NoError(t, row.Scan(&result))
+		assert.Equal(t, 1, result)
+	}
+}
+
+func (m migrationTest0015) RunAssertsAfterMigrationDown(t *testing.T, db *sql.DB) {
+	indexes := []string{
+		"idx_receipt_tx_index",
+	}
+	// Check indexes removing
+	for _, idx := range indexes {
+		// getIndex
+		const getIndex = `SELECT count(*) FROM pg_indexes WHERE indexname = $1;`
+		row := db.QueryRow(getIndex, idx)
+		var result int
+		assert.NoError(t, row.Scan(&result))
+		assert.Equal(t, 0, result)
+	}
+}
+
+func TestMigration0015(t *testing.T) {
+	runMigrationTest(t, 15, migrationTest0015{})
+}

state/pgstatestorage/transaction.go

@@ -377,7 +377,13 @@ func scanLogs(rows pgx.Rows) ([]*types.Log, error) {
 
 // GetTxsByBlockNumber returns all the txs in a given block
 func (p *PostgresStorage) GetTxsByBlockNumber(ctx context.Context, blockNumber uint64, dbTx pgx.Tx) ([]*types.Transaction, error) {
-	const getTxsByBlockNumSQL = "SELECT encoded FROM state.transaction WHERE l2_block_num = $1"
+	const getTxsByBlockNumSQL = `SELECT t.encoded 
+	   FROM state.transaction t
+	   JOIN state.receipt r
+	     ON t.hash = r.tx_hash
+	  WHERE t.l2_block_num = $1
+	    AND r.block_num = $1
+	  ORDER by r.tx_index ASC`
 
 	q := p.getExecQuerier(dbTx)
 	rows, err := q.Query(ctx, getTxsByBlockNumSQL, blockNumber)

state/trace.go

@@ -49,28 +49,23 @@ func (s *State) DebugTransaction(ctx context.Context, transactionHash common.Has
 		return nil, err
 	}
 
-	// if tx index is zero, we need to get the state root from the previous block
-	// else we need to get the state root from the previous tx
+	// the old state root is the previous block state root
 	var oldStateRoot common.Hash
-	if receipt.TransactionIndex == 0 {
-		// get the previous L2 Block
-		previousL2BlockNumber := uint64(0)
-		if receipt.BlockNumber.Uint64() > 0 {
-			previousL2BlockNumber = receipt.BlockNumber.Uint64() - 1
-		}
-		previousL2Block, err := s.GetL2BlockByNumber(ctx, previousL2BlockNumber, dbTx)
-		if err != nil {
-			return nil, err
-		}
-		oldStateRoot = previousL2Block.Root()
-	} else {
-		previousTx := l2Block.Transactions()[receipt.TransactionIndex-1]
-		// gets the tx receipt
-		previousReceipt, err := s.GetTransactionReceipt(ctx, previousTx.Hash(), dbTx)
-		if err != nil {
-			return nil, err
-		}
-		oldStateRoot = common.BytesToHash(previousReceipt.PostState)
+	previousL2BlockNumber := uint64(0)
+	if receipt.BlockNumber.Uint64() > 0 {
+		previousL2BlockNumber = receipt.BlockNumber.Uint64() - 1
+	}
+	previousL2Block, err := s.GetL2BlockByNumber(ctx, previousL2BlockNumber, dbTx)
+	if err != nil {
+		return nil, err
+	}
+	oldStateRoot = previousL2Block.Root()
+
+	// since the executor only stores the state roots by block, we need to
+	// execute all the txs in the block until the tx we want to trace
+	var txsToEncode []types.Transaction
+	for i := 0; i <= int(receipt.TransactionIndex); i++ {
+		txsToEncode = append(txsToEncode, *l2Block.Transactions()[i])
 	}
 
 	// gets batch that including the l2 block
@@ -111,7 +106,7 @@ func (s *State) DebugTransaction(ctx context.Context, transactionHash common.Has
 			}
 		}
 		// generate batch l2 data for the transaction
-		batchL2Data, err := EncodeTransactions([]types.Transaction{*tx}, []uint8{MaxEffectivePercentage}, forkId)
+		batchL2Data, err := EncodeTransactions(txsToEncode, []uint8{MaxEffectivePercentage}, forkId)
 		if err != nil {
 			return nil, err
 		}
@@ -192,7 +187,7 @@ func (s *State) DebugTransaction(ctx context.Context, transactionHash common.Has
 		deltaTimestamp := uint32(uint64(time.Now().Unix()) - l2Block.Time())
 		transactions := s.BuildChangeL2Block(deltaTimestamp, uint32(0))
 
-		batchL2Data, err := EncodeTransactions([]types.Transaction{*tx}, []uint8{MaxEffectivePercentage}, forkId)
+		batchL2Data, err := EncodeTransactions(txsToEncode, []uint8{MaxEffectivePercentage}, forkId)
 		if err != nil {
 			log.Errorf("error encoding transaction ", err)
 			return nil, err