backend/account: fix bugs in account discovery

Recent commit 726289c made the account
Initialization asynchronous, moving the `account.ensureAddresses()` call
on a separate thread. This caused a regression inside
`backend.checkAccountUsed()` where the method wasn't waiting for the
complete account synchronization before marking it as used.

This commit fixes the issue waiting for account sync before checking if
it used.

This also fixes the `backend.Accounts()` method, that was returning the
original `backend.accounts` object instead of a copy. This caused the
caller to read the account list without a proper lock, causing weird
behaviors during account discovery.

Author: Beerosagos

backend/accounts.go

@@ -1533,45 +1533,53 @@ func (backend *Backend) checkAccountUsed(account accounts.Interface) {
 		log.WithError(err).Error("error initializing account")
 		return
 	}
-	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
-	}
-	log.Info("marking account as used")
-	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")
+	f := func() {
+		txs, err := account.Transactions()
+		if err != nil {
+			log.WithError(err).Error("discoverAccount")
+			return
 		}
-		acct.Used = true
-		acct.HiddenBecauseUnused = false
 
-		// We only really show the account to the user now, so this is the moment to set the
-		// watchonly flag on it if the user has the accont's keystore's watchonly setting enabled.
-		rootFingerprint, err := acct.SigningConfigurations.RootFingerprint()
+		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 {
+			acct := accountsConfig.Lookup(account.Config().Config.Code)
+			if acct == nil {
+				return errp.Newf("could not find account")
+			}
+			acct.Used = true
+			acct.HiddenBecauseUnused = false
+
+			// We only really show the account to the user now, so this is the moment to set the
+			// watchonly flag on it if the user has the accont's keystore's watchonly setting enabled.
+			rootFingerprint, err := acct.SigningConfigurations.RootFingerprint()
+			if err != nil {
+				return err
+			}
+			if accountsConfig.IsKeystoreWatchonly(rootFingerprint) {
+				t := true
+				acct.Watch = &t
+			}
+
+			return nil
+		})
 		if err != nil {
-			return err
+			log.WithError(err).Error("checkAccountUsed")
+			return
 		}
-		if accountsConfig.IsKeystoreWatchonly(rootFingerprint) {
-			t := true
-			acct.Watch = &t
+		backend.emitAccountsStatusChanged()
+		backend.maybeAddHiddenUnusedAccounts()
+	}
+	account.Observe(func(event observable.Event) {
+		if event.Subject == string(accountsTypes.EventSyncDone) {
+			f()
 		}
-
-		return nil
 	})
-	if err != nil {
-		log.WithError(err).Error("checkAccountUsed")
-		return
-	}
-	backend.emitAccountsStatusChanged()
-	backend.maybeAddHiddenUnusedAccounts()
 }
 
 // LookupEthAccountCode takes an Ethereum address and returns the corresponding account code and account name

backend/backend.go

@@ -590,7 +590,9 @@ func (backend *Backend) Testing() bool {
 // Accounts returns the current accounts of the backend.
 func (backend *Backend) Accounts() AccountsList {
 	defer backend.accountsAndKeystoreLock.RLock()()
-	return backend.accounts
+	accounts := AccountsList{}
+	accounts = append(accounts, backend.accounts...)
+	return accounts
 }
 
 // KeystoreTotalAmount represents the total balance amount of the accounts belonging to a keystore.