maintenance: only check if an account is used if not already set.

When an account is set as used, there is no more need to check it again.
By exiting early if an account is already used, we avoid a call to Transactions().

Author: bznein

backend/accounts.go

@@ -1722,20 +1722,23 @@ func (backend *Backend) checkAccountUsed(account accounts.Interface) {
 			return
 		}
 	}
+
 	log := backend.log.WithField("accountCode", account.Config().Config.Code)
-	txs, err := account.Transactions()
-	if err != nil {
-		log.WithError(err).Error("discoverAccount")
-		return
-	}
+	if !account.Config().Config.Used {
+		txs, err := account.Transactions()
+		if err != nil {
+			log.WithError(err).Error("discoverAccount")
+			return
+		}
 
-	if len(txs) == 0 {
-		// Invoke this here too because even if an account is unused, we scan up to 5 accounts.
-		backend.maybeAddHiddenUnusedAccounts()
-		return
+		if len(txs) == 0 {
+			// Invoke this here too because even if an account is unused, we scan up to 5 accounts.
+			backend.maybeAddHiddenUnusedAccounts()
+			return
+		}
 	}
 	log.Info("marking account as used")
-	err = backend.config.ModifyAccountsConfig(func(accountsConfig *config.AccountsConfig) error {
+	err := backend.config.ModifyAccountsConfig(func(accountsConfig *config.AccountsConfig) error {
 		acct := accountsConfig.Lookup(account.Config().Config.Code)
 		if acct == nil {
 			return errp.Newf("could not find account")

backend/accounts_test.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/BitBoxSwiss/bitbox-wallet-app/backend/accounts"
+	accountsMocks "github.com/BitBoxSwiss/bitbox-wallet-app/backend/accounts/mocks"
 	accountsTypes "github.com/BitBoxSwiss/bitbox-wallet-app/backend/accounts/types"
 	"github.com/BitBoxSwiss/bitbox-wallet-app/backend/coins/btc"
 	"github.com/BitBoxSwiss/bitbox-wallet-app/backend/coins/btc/addresses"
@@ -1676,3 +1677,60 @@ func TestAccountsFiatAndCoinBalance(t *testing.T) {
 	}
 
 }
+
+func TestCheckAccountUsed(t *testing.T) {
+	b := newBackend(t, testnetDisabled, regtestDisabled)
+	b.tstCheckAccountUsed = nil
+	defer b.Close()
+	accountMocks := map[accountsTypes.Code]*accountsMocks.InterfaceMock{}
+	// A Transactions function that always returns one transaction, so the account is always used.
+	txFunc := func() (accounts.OrderedTransactions, error) {
+		return accounts.OrderedTransactions{&accounts.TransactionData{}}, nil
+	}
+
+	b.makeBtcAccount = func(config *accounts.AccountConfig, coin *btc.Coin, gapLimits *types.GapLimits, getAddress func(coinpkg.Code, blockchain.ScriptHashHex) (*addresses.AccountAddress, error), log *logrus.Entry) accounts.Interface {
+		accountMock := MockBtcAccount(t, config, coin, gapLimits, log)
+		accountMock.TransactionsFunc = txFunc
+		accountMocks[config.Config.Code] = accountMock
+		return accountMock
+	}
+
+	b.makeEthAccount = func(config *accounts.AccountConfig, coin *eth.Coin, httpClient *http.Client, log *logrus.Entry) accounts.Interface {
+		accountMock := MockEthAccount(config, coin, httpClient, log)
+		accountMock.TransactionsFunc = txFunc
+		accountMocks[config.Config.Code] = accountMock
+		return accountMock
+	}
+
+	ks1 := makeBitBox02Multi()
+
+	ks1Fingerprint, err := ks1.RootFingerprint()
+	require.NoError(t, err)
+
+	b.registerKeystore(ks1)
+	require.NoError(t, b.SetWatchonly(ks1Fingerprint, true))
+
+	accountsByKestore, err := b.AccountsByKeystore()
+	require.NoError(t, err)
+
+	accountList, ok := accountsByKestore[hex.EncodeToString(ks1Fingerprint)]
+	require.True(t, ok, "Expected accounts for keystore with fingerprint %s", hex.EncodeToString(ks1Fingerprint))
+
+	// Check all accounts, make sure they are set as used.
+	for _, acct := range accountList {
+		mock, ok := accountMocks[acct.Config().Config.Code]
+		require.True(t, ok, "No mock for account %s", acct.Config().Config.Code)
+
+		b.checkAccountUsed(acct)
+		// Ensure that Transactions is called
+		require.Len(t, mock.TransactionsCalls(), 1)
+		require.True(t, acct.Config().Config.Used)
+
+		// Call checkAccountUsed again, Transactions should not be called again.
+		b.checkAccountUsed(acct)
+		require.Len(t, mock.TransactionsCalls(), 1)
+		// And Used should still be true.
+		require.True(t, acct.Config().Config.Used)
+	}
+
+}