multi: make canceled invoice garbage collection configurable

This commit extends the application config with a flag to control canceled
invoice garbage collection upon startup.

config.go

@@ -242,6 +242,8 @@ type Config struct {
 
 	KeysendHoldTime time.Duration `long:"keysend-hold-time" description:"If non-zero, keysend payments are accepted but not immediately settled. If the payment isn't settled manually after the specified time, it is canceled automatically. [experimental]"`
 
+	GcCanceledInvoicesOnStartup bool `long:"gc-canceled-invoices-on-startup" description:"If true, we'll attempt to garbage collect canceled invoices upon start."`
+
 	Routing *routing.Conf `group:"routing" namespace:"routing"`
 
 	Workers *lncfg.Workers `group:"workers" namespace:"workers"`

invoices/invoiceregistry.go

@@ -57,6 +57,10 @@ type RegistryConfig struct {
 	// send payments.
 	AcceptKeySend bool
 
+	// GcCanceledInvoicesOnStartup if set, we'll attempt to garbage collect
+	// all canceled invoices upon start.
+	GcCanceledInvoicesOnStartup bool
+
 	// KeysendHoldTime indicates for how long we want to accept and hold
 	// spontaneous keysend payments.
 	KeysendHoldTime time.Duration
@@ -171,7 +175,9 @@ func (i *InvoiceRegistry) scanInvoicesOnStart() error {
 
 		if invoice.IsPending() {
 			pending[paymentHash] = invoice
-		} else if invoice.State == channeldb.ContractCanceled {
+		} else if i.cfg.GcCanceledInvoicesOnStartup &&
+			invoice.State == channeldb.ContractCanceled {
+
 			// Consider invoice for removal if it is already
 			// canceled. Invoices that are expired but not yet
 			// canceled, will be queued up for cancellation after

invoices/invoiceregistry_test.go

@@ -1093,6 +1093,7 @@ func TestOldInvoiceRemovalOnStart(t *testing.T) {
 	cfg := RegistryConfig{
 		FinalCltvRejectDelta:        testFinalCltvRejectDelta,
 		Clock:                       testClock,
+		GcCanceledInvoicesOnStartup: true,
 	}
 
 	expiryWatcher := NewInvoiceExpiryWatcher(cfg.Clock)

server.go

@@ -400,6 +400,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr, chanDB *channeldb.DB,
 		HtlcHoldDuration:            invoices.DefaultHtlcHoldDuration,
 		Clock:                       clock.NewDefaultClock(),
 		AcceptKeySend:               cfg.AcceptKeySend,
+		GcCanceledInvoicesOnStartup: cfg.GcCanceledInvoicesOnStartup,
 		KeysendHoldTime:             cfg.KeysendHoldTime,
 	}