OEV-605: Adds purging unstarted txs to txmv2

[cl-efornaciari]

adds purging unstarted txs beyond the cutoff

[github-actions]

👋 cl-efornaciari, thanks for creating this pull request!

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[dimriou]

It's safer to check like this:

Suggested change

	if prunedTxIDs != nil {
	if len(prunedTxIDs) != 0 {

because depending on the implementation, a slice could be != nil, but still have 0 elements. len method is safe to use even for nil slices.

[dimriou]

Does the work 👍 . Here's a more idiomatic way for future reference:

Suggested change

	// Shouldn't call lock because it's being called by a method that already has the lock
	func (m *InMemoryStore) pruneUnstartedTransactionsWithinDuration(threshold time.Duration) []uint64 {
	var txIDsToPrune []uint64
	idxTxToRetain := 0
	for ; idxTxToRetain < len(m.UnstartedTransactions); idxTxToRetain++ {
	tx := m.UnstartedTransactions[idxTxToRetain]
	if time.Since(tx.CreatedAt) < threshold {
	break
	}
	txIDsToPrune = append(txIDsToPrune, tx.ID)
	delete(m.Transactions, tx.ID)
	m.UnstartedTransactions[idxTxToRetain] = nil // prevent memory leak
	}
	if len(txIDsToPrune) == 0 {
	return nil
	}
	m.UnstartedTransactions = m.UnstartedTransactions[idxTxToRetain:]
	sort.Slice(txIDsToPrune, func(i, j int) bool { return txIDsToPrune[i] < txIDsToPrune[j] })
	return txIDsToPrune
	}
	// Shouldn't call lock because it's being called by a method that already has the lock
	func (m *InMemoryStore) pruneUnstartedTransactionsWithinDuration(threshold time.Duration) (txIDsToPrune []uint64) {
	for i, tx := range m.UnstartedTransactions {
	if time.Since(tx.CreatedAt) < threshold {
	m.UnstartedTransactions = m.UnstartedTransactions[i:]
	return txIDsToPrune // you can sort before this if you want to
	}
	txIDsToPrune = append(txIDsToPrune, tx.ID)
	delete(m.Transactions, tx.ID)
	m.UnstartedTransactions[i] = nil // prevent memory leak
	}
	m.UnstartedTransactions = m.UnstartedTransactions[:0]
	return
	}

[dimriou]

This will panic. Needs to be before the check on line 299.