multi: make the next protocol version optional

loopd/config.go

@@ -149,6 +149,8 @@ type Config struct {
 	TotalPaymentTimeout time.Duration `long:"totalpaymenttimeout" description:"The timeout to use for off-chain payments."`
 	MaxPaymentRetries   int           `long:"maxpaymentretries" description:"The maximum number of times an off-chain payment may be retried."`
 
+	EnableExperimental bool `long:"experimental" description:"Enable experimental features: taproot HTLCs and MuSig2 loop out sweeps."`
+
 	Lnd *lndConfig `group:"lnd" namespace:"lnd"`
 
 	Server *loopServerConfig `group:"server" namespace:"server"`
@@ -185,6 +187,7 @@ func DefaultConfig() Config {
 		LoopOutMaxParts:     defaultLoopOutMaxParts,
 		TotalPaymentTimeout: defaultTotalPaymentTimeout,
 		MaxPaymentRetries:   defaultMaxPaymentRetries,
+		EnableExperimental:  false,
 		Lnd: &lndConfig{
 			Host:         "localhost:10009",
 			MacaroonPath: DefaultLndMacaroonPath,

loopd/daemon.go

@@ -348,6 +348,12 @@ func (d *Daemon) startWebServers() error {
 // this method fails with an error then no goroutine was started yet and no
 // cleanup is necessary. If it succeeds, then goroutines have been spawned.
 func (d *Daemon) initialize(withMacaroonService bool) error {
+	if d.cfg.EnableExperimental {
+		loopdb.EnableExperimentalProtocol()
+	}
+
+	log.Infof("Protocol version: %v", loopdb.CurrentProtocolVersion())
+
 	// If no swap server is specified, use the default addresses for mainnet
 	// and testnet.
 	if d.cfg.Server.Host == "" {

loopdb/protocol_version.go

@@ -59,18 +59,50 @@ const (
 	// started saving protocol version with swaps.
 	ProtocolVersionUnrecorded ProtocolVersion = math.MaxUint32
 
-	// CurrentRPCProtocolVersion defines the version of the RPC protocol
+	// stableRPCProtocolVersion defines the current stable RPC protocol
-	// that is currently supported by the loop client.
+	// version.
-	CurrentRPCProtocolVersion = looprpc.ProtocolVersion_HTLC_V3
+	stableRPCProtocolVersion = looprpc.ProtocolVersion_ROUTING_PLUGIN
 
-	// CurrentInternalProtocolVersion defines the RPC current protocol in
+	// experimentalRPCProtocolVersion defines the RPC protocol version that
-	// the internal representation.
+	// includes all currently experimentally released features.
-	CurrentInternalProtocolVersion = ProtocolVersion(CurrentRPCProtocolVersion)
+	experimentalRPCProtocolVersion = looprpc.ProtocolVersion_HTLC_V3
 )
 
+var (
+	// currentRPCProtocolVersion holds the version of the RPC protocol
+	// that the client selected to use for new swaps. Shouldn't be lower
+	// than the previous protocol version.
+	currentRPCProtocolVersion = stableRPCProtocolVersion
+)
+
+// CurrentRPCProtocolVersion returns the RPC protocol version selected to be
+// used for new swaps.
+func CurrentRPCProtocolVersion() looprpc.ProtocolVersion {
+	return currentRPCProtocolVersion
+}
+
+// CurrentProtocolVersion returns the internal protocol version selected to be
+// used for new swaps.
+func CurrentProtocolVersion() ProtocolVersion {
+	return ProtocolVersion(currentRPCProtocolVersion)
+}
+
+// EnableExperimentalProtocol sets the current protocol version to include all
+// experimental features. Do not call this function directly: used in loopd and
+// unit tests only.
+func EnableExperimentalProtocol() {
+	currentRPCProtocolVersion = experimentalRPCProtocolVersion
+}
+
+// ResetCurrentProtocolVersion resets the current protocol version to the stable
+// protocol. Note: used in integration tests only!
+func ResetCurrentProtocolVersion() {
+	currentRPCProtocolVersion = stableRPCProtocolVersion
+}
+
 // Valid returns true if the value of the ProtocolVersion is valid.
 func (p ProtocolVersion) Valid() bool {
-	return p <= CurrentInternalProtocolVersion
+	return p <= ProtocolVersion(experimentalRPCProtocolVersion)
 }
 
 // String returns the string representation of a protocol version.

loopdb/protocol_version_test.go

@@ -48,12 +48,19 @@ func TestProtocolVersionSanity(t *testing.T) {
 
 	// Finally test that the current version contants are up to date
 	require.Equal(t,
-		CurrentInternalProtocolVersion,
+		CurrentProtocolVersion(),
-		versions[len(versions)-1],
+		versions[len(versions)-2],
 	)
 
 	require.Equal(t,
-		uint32(CurrentInternalProtocolVersion),
+		uint32(CurrentProtocolVersion()),
-		uint32(CurrentRPCProtocolVersion),
+		uint32(CurrentRPCProtocolVersion()),
+	)
+
+	EnableExperimentalProtocol()
+
+	require.Equal(t,
+		CurrentProtocolVersion(),
+		ProtocolVersion(experimentalRPCProtocolVersion),
 	)
 }

loopin.go

@@ -244,7 +244,7 @@ func newLoopInSwap(globalCtx context.Context, cfg *swapConfig,
 			MaxMinerFee:      request.MaxMinerFee,
 			MaxSwapFee:       request.MaxSwapFee,
 			Label:            request.Label,
-			ProtocolVersion:  loopdb.CurrentInternalProtocolVersion,
+			ProtocolVersion:  loopdb.CurrentProtocolVersion(),
 		},
 	}
 

loopout.go

@@ -177,7 +177,7 @@ func newLoopOutSwap(globalCtx context.Context, cfg *swapConfig,
 			MaxMinerFee:      request.MaxMinerFee,
 			MaxSwapFee:       request.MaxSwapFee,
 			Label:            request.Label,
-			ProtocolVersion:  loopdb.CurrentInternalProtocolVersion,
+			ProtocolVersion:  loopdb.CurrentProtocolVersion(),
 		},
 		OutgoingChanSet: chanSet,
 	}

swap_server_client.go

@@ -174,7 +174,7 @@ func (s *grpcSwapServerClient) GetLoopOutTerms(ctx context.Context) (
 	defer rpcCancel()
 	terms, err := s.server.LoopOutTerms(rpcCtx,
 		&looprpc.ServerLoopOutTermsRequest{
-			ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		},
 	)
 	if err != nil {
@@ -199,7 +199,7 @@ func (s *grpcSwapServerClient) GetLoopOutQuote(ctx context.Context,
 		&looprpc.ServerLoopOutQuoteRequest{
 			Amt:                     uint64(amt),
 			SwapPublicationDeadline: swapPublicationDeadline.Unix(),
-			ProtocolVersion:         loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion:         loopdb.CurrentRPCProtocolVersion(),
 			Expiry:                  expiry,
 		},
 	)
@@ -231,7 +231,7 @@ func (s *grpcSwapServerClient) GetLoopInTerms(ctx context.Context) (
 	defer rpcCancel()
 	terms, err := s.server.LoopInTerms(rpcCtx,
 		&looprpc.ServerLoopInTermsRequest{
-			ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		},
 	)
 	if err != nil {
@@ -258,7 +258,7 @@ func (s *grpcSwapServerClient) GetLoopInQuote(ctx context.Context,
 
 	req := &looprpc.ServerLoopInQuoteRequest{
 		Amt:             uint64(amt),
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		Pubkey:          pubKey[:],
 	}
 
@@ -343,7 +343,7 @@ func (s *grpcSwapServerClient) Probe(ctx context.Context, amt btcutil.Amount,
 	req := &looprpc.ServerProbeRequest{
 		Amt:             uint64(amt),
 		Target:          target[:],
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		RouteHints:      rpcRouteHints,
 	}
 
@@ -368,7 +368,7 @@ func (s *grpcSwapServerClient) NewLoopOutSwap(ctx context.Context,
 			Amt:                     uint64(amount),
 			ReceiverKey:             receiverKey[:],
 			SwapPublicationDeadline: swapPublicationDeadline.Unix(),
-			ProtocolVersion:         loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion:         loopdb.CurrentRPCProtocolVersion(),
 			Expiry:                  expiry,
 			UserAgent:               UserAgent(initiator),
 		},
@@ -403,7 +403,7 @@ func (s *grpcSwapServerClient) PushLoopOutPreimage(ctx context.Context,
 
 	_, err := s.server.LoopOutPushPreimage(rpcCtx,
 		&looprpc.ServerLoopOutPushPreimageRequest{
-			ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 			Preimage:        preimage[:],
 		},
 	)
@@ -424,7 +424,7 @@ func (s *grpcSwapServerClient) NewLoopInSwap(ctx context.Context,
 		Amt:             uint64(amount),
 		SenderKey:       senderKey[:],
 		SwapInvoice:     swapInvoice,
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		ProbeInvoice:    probeInvoice,
 		UserAgent:       UserAgent(initiator),
 	}
@@ -469,7 +469,7 @@ func (s *grpcSwapServerClient) SubscribeLoopInUpdates(ctx context.Context,
 
 	resp, err := s.server.SubscribeLoopInUpdates(
 		ctx, &looprpc.SubscribeUpdatesRequest{
-			ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 			SwapHash:        hash[:],
 		},
 	)
@@ -500,7 +500,7 @@ func (s *grpcSwapServerClient) SubscribeLoopOutUpdates(ctx context.Context,
 
 	resp, err := s.server.SubscribeLoopOutUpdates(
 		ctx, &looprpc.SubscribeUpdatesRequest{
-			ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+			ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 			SwapHash:        hash[:],
 		},
 	)
@@ -639,7 +639,7 @@ func (s *grpcSwapServerClient) CancelLoopOutSwap(ctx context.Context,
 	details *outCancelDetails) error {
 
 	req := &looprpc.CancelLoopOutSwapRequest{
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		SwapHash:        details.hash[:],
 		PaymentAddress:  details.paymentAddr[:],
 	}
@@ -660,7 +660,7 @@ func (s *grpcSwapServerClient) RecommendRoutingPlugin(ctx context.Context,
 	swapHash lntypes.Hash, paymentAddr [32]byte) (RoutingPluginType, error) {
 
 	req := &looprpc.RecommendRoutingPluginReq{
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		SwapHash:        swapHash[:],
 		PaymentAddress:  paymentAddr[:],
 	}
@@ -704,7 +704,7 @@ func (s *grpcSwapServerClient) ReportRoutingResult(ctx context.Context,
 	}
 
 	req := &looprpc.ReportRoutingResultReq{
-		ProtocolVersion: loopdb.CurrentRPCProtocolVersion,
+		ProtocolVersion: loopdb.CurrentRPCProtocolVersion(),
 		SwapHash:        swapHash[:],
 		PaymentAddress:  paymentAddr[:],
 		Plugin:          rpcRoutingPlugin,