accounts: add new AddAccountInvoice Store method

And use it instead of UpdateAccount for the InterceptorService's
AssociateInvoice method.

Author: ellemouton

accounts/interface.go

@@ -226,6 +226,10 @@ type Store interface {
 		newBalance fn.Option[lnwire.MilliSatoshi],
 		newExpiry fn.Option[time.Time]) error
 
+	// AddAccountInvoice adds an invoice hash to an account.
+	AddAccountInvoice(ctx context.Context, id AccountID,
+		hash lntypes.Hash) error
+
 	// RemoveAccount finds an account by its ID and removes it from the¨
 	// store.
 	RemoveAccount(ctx context.Context, id AccountID) error

accounts/service.go

@@ -438,15 +438,15 @@ func (s *InterceptorService) AssociateInvoice(ctx context.Context, id AccountID,
 	s.Lock()
 	defer s.Unlock()
 
-	account, err := s.store.Account(ctx, id)
+	err := s.store.AddAccountInvoice(ctx, id, hash)
 	if err != nil {
-		return err
+		return fmt.Errorf("error adding invoice to account: %w", err)
 	}
 
-	account.Invoices[hash] = struct{}{}
+	// If the above was successful, then we update our in-memory map.
 	s.invoiceToAccount[hash] = id
 
-	return s.store.UpdateAccount(ctx, account)
+	return nil
 }
 
 // PaymentErrored removes a pending payment from the account's registered

accounts/store_kvdb.go

@@ -13,6 +13,7 @@ import (
 	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/kvdb"
+	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"go.etcd.io/bbolt"
 )
@@ -217,6 +218,21 @@ func (s *BoltStore) UpdateAccountBalanceAndExpiry(_ context.Context,
 	return s.updateAccount(id, update)
 }
 
+// AddAccountInvoice adds an invoice hash to the account with the given ID.
+//
+// NOTE: This is part of the Store interface.
+func (s *BoltStore) AddAccountInvoice(_ context.Context, id AccountID,
+	hash lntypes.Hash) error {
+
+	update := func(account *OffChainBalanceAccount) error {
+		account.Invoices[hash] = struct{}{}
+
+		return nil
+	}
+
+	return s.updateAccount(id, update)
+}
+
 func (s *BoltStore) updateAccount(id AccountID,
 	updateFn func(*OffChainBalanceAccount) error) error {
 

accounts/store_test.go

@@ -177,6 +177,53 @@ func TestAccountUpdateMethods(t *testing.T) {
 		require.NoError(t, err)
 		assertBalanceAndExpiry(newBalance, newExpiry)
 	})
+
+	t.Run("AddAccountInvoice", func(t *testing.T) {
+		store := NewTestDB(t)
+
+		acct, err := store.NewAccount(ctx, 0, time.Time{}, "foo")
+		require.NoError(t, err)
+
+		assertInvoices := func(invoices ...lntypes.Hash) {
+			dbAcct, err := store.Account(ctx, acct.ID)
+			require.NoError(t, err)
+
+			// First make sure the number of invoices match before
+			// de-duping the hashes.
+			require.Len(t, dbAcct.Invoices, len(invoices))
+
+			dbInvs := make([]lntypes.Hash, 0, len(dbAcct.Invoices))
+			for hash := range dbAcct.Invoices {
+				dbInvs = append(dbInvs, hash)
+			}
+
+			require.ElementsMatch(t, invoices, dbInvs)
+		}
+
+		// The account initially has no invoices.
+		assertInvoices()
+
+		// Add an invoice to the account.
+		hash1 := lntypes.Hash{1, 2, 3, 4}
+		err = store.AddAccountInvoice(ctx, acct.ID, hash1)
+		require.NoError(t, err)
+
+		assertInvoices(hash1)
+
+		// Assert that adding the same invoice again does not change the
+		// state.
+		err = store.AddAccountInvoice(ctx, acct.ID, hash1)
+		require.NoError(t, err)
+
+		assertInvoices(hash1)
+
+		// Now add a second invoice.
+		hash2 := lntypes.Hash{5, 6, 7, 8}
+		err = store.AddAccountInvoice(ctx, acct.ID, hash2)
+		require.NoError(t, err)
+
+		assertInvoices(hash1, hash2)
+	})
 }
 
 // TestLastInvoiceIndexes makes sure the last known invoice indexes can be