btcwallet: remove LookupAccount because of non-deterministic result

In theory, it should be only one custom account with a given name. However,
users could have created custom accounts with various key scopes. In that case,
'LookupAccount' has a non deterministic behaviour. To fix that, we browse
through all key scopes (deterministically) and return the first account we found.

lnwallet/btcwallet/btcwallet.go

@@ -82,11 +82,6 @@ var (
 	// requested for the default imported account within the wallet.
 	errNoImportedAddrGen = errors.New("addresses cannot be generated for " +
 		"the default imported account")
-
-	// errIncompatibleAccountAddr is an error returned when the type of a
-	// new address being requested is incompatible with the account.
-	errIncompatibleAccountAddr = errors.New("incompatible address type " +
-		"for account")
 )
 
 // BtcWallet is an implementation of the lnwallet.WalletController interface
@@ -516,18 +511,14 @@ func (b *BtcWallet) keyScopeForAccountAddr(accountName string,
 		return addrKeyScope, defaultAccount, nil
 	}
 
-	// Otherwise, look up the account's key scope and check that it supports
+	// Otherwise, look up the custom account and if it supports the given
-	// the requested address type.
+	// key scope.
-	keyScope, account, err := b.wallet.LookupAccount(accountName)
+	accountNumber, err := b.wallet.AccountNumber(addrKeyScope, accountName)
 	if err != nil {
 		return waddrmgr.KeyScope{}, 0, err
 	}
 
-	if keyScope != addrKeyScope {
+	return addrKeyScope, accountNumber, nil
-		return waddrmgr.KeyScope{}, 0, errIncompatibleAccountAddr
-	}
-
-	return keyScope, account, nil
 }
 
 // NewAddress returns the next external or internal address for the wallet

lnwallet/btcwallet/psbt.go

@@ -97,7 +97,7 @@ func (b *BtcWallet) FundPsbt(packet *psbt.Packet, minConfs int32,
 				"custom change type for custom accounts")
 		}
 
-		scope, account, err := b.wallet.LookupAccount(accountName)
+		scope, account, err := b.lookupFirstCustomAccount(accountName)
 		if err != nil {
 			return 0, err
 		}
@@ -512,7 +512,7 @@ func (b *BtcWallet) FinalizePsbt(packet *psbt.Packet, accountName string) error
 	// number to determine if the inputs belonging to this account should be
 	// signed.
 	default:
-		scope, account, err := b.wallet.LookupAccount(accountName)
+		scope, account, err := b.lookupFirstCustomAccount(accountName)
 		if err != nil {
 			return err
 		}
@@ -522,3 +522,36 @@ func (b *BtcWallet) FinalizePsbt(packet *psbt.Packet, accountName string) error
 
 	return b.wallet.FinalizePsbt(keyScope, accountNum, packet)
 }
+
+// lookupFirstCustomAccount returns the first custom account found. In theory,
+// there should be only one custom account for the given name. However, due to a
+// lack of check, users could have created custom accounts with various key
+// scopes. This behaviour has been fixed but, we still need to handle this
+// specific case to avoid non-deterministic behaviour implied by LookupAccount.
+func (b *BtcWallet) lookupFirstCustomAccount(
+	name string) (waddrmgr.KeyScope, uint32, error) {
+
+	var (
+		account  *waddrmgr.AccountProperties
+		keyScope waddrmgr.KeyScope
+	)
+	for _, scope := range waddrmgr.DefaultKeyScopes {
+		var err error
+		account, err = b.wallet.AccountPropertiesByName(scope, name)
+		if waddrmgr.IsError(err, waddrmgr.ErrAccountNotFound) {
+			continue
+		}
+		if err != nil {
+			return keyScope, 0, err
+		}
+
+		keyScope = scope
+
+		break
+	}
+	if account == nil {
+		return waddrmgr.KeyScope{}, 0, newAccountNotFoundError(name)
+	}
+
+	return keyScope, account.AccountNumber, nil
+}