chain,wallet: handle no transactions and move locking to methods

chain/manager.go

@@ -941,6 +941,8 @@ func (m *Manager) V2TransactionSet(basis types.ChainIndex, txn types.V2Transacti
 	_, txns, err := m.updateV2TransactionSet(basis, []types.V2Transaction{txn})
 	if err != nil {
 		return types.ChainIndex{}, nil, fmt.Errorf("failed to update transaction set basis: %w", err)
+	} else if len(txns) == 0 {
+		return types.ChainIndex{}, nil, errors.New("no transactions to broadcast")
 	}
 	txn = txns[0]
 

wallet/update.go

@@ -285,8 +285,11 @@ func appliedEvents(cau chain.ApplyUpdate, walletAddress types.Address) (events [
 	return
 }
 
-// applyChainState atomically applies a chain update
-func applyChainState(tx UpdateTx, address types.Address, cau chain.ApplyUpdate) error {
+// applyChainUpdate atomically applies a chain update
+func (sw *SingleAddressWallet) applyChainUpdate(tx UpdateTx, address types.Address, cau chain.ApplyUpdate) error {
+	sw.mu.Lock()
+	defer sw.mu.Unlock()
+
 	// update current state elements
 	stateElements, err := tx.WalletStateElements()
 	if err != nil {
@@ -321,11 +324,15 @@ func applyChainState(tx UpdateTx, address types.Address, cau chain.ApplyUpdate)
 	if err := tx.WalletApplyIndex(cau.State.Index, createdUTXOs, spentUTXOs, appliedEvents(cau, address), cau.Block.Timestamp); err != nil {
 		return fmt.Errorf("failed to apply index: %w", err)
 	}
+	sw.tip = cau.State.Index
 	return nil
 }
 
 // revertChainUpdate atomically reverts a chain update from a wallet
-func revertChainUpdate(tx UpdateTx, revertedIndex types.ChainIndex, address types.Address, cru chain.RevertUpdate) error {
+func (sw *SingleAddressWallet) revertChainUpdate(tx UpdateTx, revertedIndex types.ChainIndex, address types.Address, cru chain.RevertUpdate) error {
+	sw.mu.Lock()
+	defer sw.mu.Unlock()
+
 	var removedUTXOs, unspentUTXOs []types.SiacoinElement
 	cru.ForEachSiacoinElement(func(se types.SiacoinElement, created, spent bool) {
 		switch {
@@ -360,6 +367,7 @@ func revertChainUpdate(tx UpdateTx, revertedIndex types.ChainIndex, address type
 	if err := tx.UpdateWalletStateElements(stateElements); err != nil {
 		return fmt.Errorf("failed to update state elements: %w", err)
 	}
+	sw.tip = revertedIndex
 	return nil
 }
 
@@ -371,25 +379,17 @@ func (sw *SingleAddressWallet) UpdateChainState(tx UpdateTx, reverted []chain.Re
 			ID:     cru.Block.ID(),
 			Height: cru.State.Index.Height + 1,
 		}
-		sw.mu.Lock()
-		err := revertChainUpdate(tx, revertedIndex, sw.addr, cru)
+		err := sw.revertChainUpdate(tx, revertedIndex, sw.addr, cru)
 		if err != nil {
-			sw.mu.Unlock()
 			return fmt.Errorf("failed to revert chain update %q: %w", cru.State.Index, err)
 		}
-		sw.tip = cru.State.Index
-		sw.mu.Unlock()
 	}
 
 	for _, cau := range applied {
-		sw.mu.Lock()
-		err := applyChainState(tx, sw.addr, cau)
+		err := sw.applyChainUpdate(tx, sw.addr, cau)
 		if err != nil {
-			sw.mu.Unlock()
 			return fmt.Errorf("failed to apply chain update %q: %w", cau.State.Index, err)
 		}
-		sw.tip = cau.State.Index
-		sw.mu.Unlock()
 	}
 	return nil
 }