walletrpc+btcwallet: no custom account with various key scopes

Currently, a user can create a custom account with various key scopes.
This is not a desired behaviour.

cmd/lncli/walletrpc_active.go

@@ -1447,6 +1447,9 @@ var importAccountCommand = cli.Command{
 	The address type can usually be inferred from the key's version, but may
 	be required for certain keys to map them into the proper scope.
 
+	If an account with the same name already exists (even with a different
+	key scope), an error will be returned.
+
 	For BIP-0044 keys, an address type must be specified as we intend to not
 	support importing BIP-0044 keys into the wallet using the legacy
 	pay-to-pubkey-hash (P2PKH) scheme. A nested witness address type will

itest/lnd_wallet_import_test.go

@@ -2,6 +2,7 @@ package itest
 
 import (
 	"bytes"
+	"fmt"
 	"testing"
 	"time"
 
@@ -468,6 +469,10 @@ func testWalletImportAccount(ht *lntest.HarnessTest) {
 		name     string
 		addrType walletrpc.AddressType
 	}{
+		{
+			name:     "standard BIP-0044",
+			addrType: walletrpc.AddressType_WITNESS_PUBKEY_HASH,
+		},
 		{
 			name: "standard BIP-0049",
 			addrType: walletrpc.
@@ -550,6 +555,34 @@ func runWalletImportAccountScenario(ht *lntest.HarnessTest,
 	}
 	dave.RPC.ImportAccount(importReq)
 
+	// Try to import an account with the same name but with a different
+	// key scope. It should return an error.
+	otherAddrType := walletrpc.AddressType_TAPROOT_PUBKEY
+	if addrType == walletrpc.AddressType_TAPROOT_PUBKEY {
+		otherAddrType--
+	}
+
+	listReq = &walletrpc.ListAccountsRequest{
+		Name:        "default",
+		AddressType: otherAddrType,
+	}
+	listResp = carol.RPC.ListAccounts(listReq)
+	require.Len(ht, listResp.Accounts, 1)
+
+	carolAccountOtherAddrType := listResp.Accounts[0]
+
+	errAccountExists := fmt.Sprintf(
+		"account '%s' already exists", importedAccount,
+	)
+
+	importReq = &walletrpc.ImportAccountRequest{
+		Name:              importedAccount,
+		ExtendedPublicKey: carolAccountOtherAddrType.ExtendedPublicKey,
+		AddressType:       otherAddrType,
+	}
+	err := dave.RPC.ImportAccountAssertErr(importReq)
+	require.ErrorContains(ht, err, errAccountExists)
+
 	// We'll generate an address for Carol from Dave's node to receive some
 	// funds.
 	externalAddr := newExternalAddr(

lntest/rpc/wallet_kit.go

@@ -235,6 +235,20 @@ func (h *HarnessRPC) ImportAccount(
 	return resp
 }
 
+// ImportAccountAssertErr makes the ImportAccount RPC call and asserts an error
+// is returned. It then returns the error.
+func (h *HarnessRPC) ImportAccountAssertErr(
+	req *walletrpc.ImportAccountRequest) error {
+
+	ctxt, cancel := context.WithTimeout(h.runCtx, DefaultTimeout)
+	defer cancel()
+
+	_, err := h.WalletKit.ImportAccount(ctxt, req)
+	require.Error(h, err)
+
+	return err
+}
+
 // ImportPublicKey makes a RPC call to the node's WalletKitClient and asserts.
 //
 //nolint:lll

lnwallet/btcwallet/btcwallet.go

@@ -843,6 +843,10 @@ func (b *BtcWallet) ListAddresses(name string,
 // The address type can usually be inferred from the key's version, but may be
 // required for certain keys to map them into the proper scope.
 //
+// For custom accounts, we will first check if there is no account with the same
+// name (even with a different key scope). No custom account should have various
+// key scopes as it will result in non-deterministic behaviour.
+//
 // For BIP-0044 keys, an address type must be specified as we intend to not
 // support importing BIP-0044 keys into the wallet using the legacy
 // pay-to-pubkey-hash (P2PKH) scheme. A nested witness address type will force
@@ -860,6 +864,22 @@ func (b *BtcWallet) ImportAccount(name string, accountPubKey *hdkeychain.Extende
 	dryRun bool) (*waddrmgr.AccountProperties, []btcutil.Address,
 	[]btcutil.Address, error) {
 
+	// For custom accounts, we first check if there is no existing account
+	// with the same name.
+	if name != lnwallet.DefaultAccountName &&
+		name != waddrmgr.ImportedAddrAccountName {
+
+		_, err := b.ListAccounts(name, nil)
+		if err == nil {
+			return nil, nil, nil,
+				fmt.Errorf("account '%s' already exists",
+					name)
+		}
+		if !waddrmgr.IsError(err, waddrmgr.ErrAccountNotFound) {
+			return nil, nil, nil, err
+		}
+	}
+
 	if !dryRun {
 		accountProps, err := b.wallet.ImportAccount(
 			name, accountPubKey, masterKeyFingerprint, addrType,