Merge cf601f3933 into fba30046eb

config.go

@@ -1012,6 +1012,18 @@ func loadConfigFile(preCfg *Config, interceptor signal.Interceptor) (*Config,
 			cfg.Lnd.ProtocolOptions.CustomMessage, lnwire.MsgError,
 		)
 
+		// tapd's RFQ subsystem enforces the agreed upon quote for asset
+		// HTLCs through lnd's HTLC interceptor. Whenever no interceptor
+		// is attached, lnd forwards HTLCs without any of those checks,
+		// which would allow asset HTLCs to be forwarded while tapd is
+		// starting up or while it is re-establishing its interception
+		// stream. We therefore require an interceptor to be present
+		// whenever tapd runs in-process, which makes lnd fail HTLCs
+		// back instead of forwarding them unchecked.
+		if cfg.TaprootAssetsMode == ModeIntegrated {
+			cfg.Lnd.RequireInterceptor = true
+		}
+
 		var err error
 		cfg.Lnd, err = lnd.ValidateConfig(
 			*cfg.Lnd, interceptor, fileParser, flagParser,

docs/release-notes/release-notes-0.17.1.md

@@ -42,6 +42,17 @@
   configurable, generous timeout (`--lndreadytimeout`, defaulting to 10
   minutes) instead of a fixed attempt count.
 
+* [Fix a startup deadlock when tapd runs in integrated
+  mode](https://github.com/lightninglabs/lightning-terminal/pull/1371):
+  litd waited for lnd to be fully synced to chain before starting its
+  sub-servers, but lnd only reports itself as synced once its blockbeat has
+  caught up, and block processing can be blocked on tapd's aux sweeper, which
+  only becomes available once tapd is started. With a channel being resolved on
+  chain, litd therefore retried the lnd client creation forever and tapd never
+  came up. We now only wait for the chain notifier, and additionally require an
+  HTLC interceptor to be attached whenever tapd runs in-process, so lnd fails
+  forwards back instead of forwarding them without any RFQ policy checks.
+
 ### Functional Changes/Additions
 
 * [Add accounts payments history subcommand](https://github.com/lightninglabs/lightning-terminal/pull/1316):
@@ -117,4 +128,5 @@
 * 0xfandom
 * bitromortac
 * Cyberguru1
+* George Tsagkarelis
 * Vandit Singh

terminal.go

@@ -1003,6 +1003,23 @@ func (g *LightningTerminal) setupFullLNDClient(ctx context.Context,
 	// so if we instruct the lndclient to wait for the wallet sync, we
 	// should be fully ready to start all our subservers. This will just
 	// block until lnd signals readiness.
+	//
+	// There is one exception to that: with both lnd and tapd running
+	// in-process, we must not wait for lnd to be synced to chain here. lnd
+	// only reports itself as synced once its blockbeat caught up, and block
+	// processing can be blocked on tapd's aux components. If for example a
+	// channel is being resolved on chain, the sweeper calls into tapd's aux
+	// sweeper, which blocks until tapd is started. As tapd is only started
+	// once we have the client below, waiting here would deadlock the
+	// startup and we'd retry forever without ever starting tapd.
+	integratedTapd := g.cfg.LndMode == ModeIntegrated &&
+		g.cfg.TaprootAssetsMode == ModeIntegrated
+	blockUntilChainSynced := !integratedTapd
+	if integratedTapd {
+		log.Infof("Not waiting for lnd to be synced to chain, as " +
+			"tapd is running in integrated mode")
+	}
+
 	log.Infof("Connecting full lnd client")
 	for {
 		g.lndClient, err = lndclient.NewLndServices(
@@ -1020,7 +1037,7 @@ func (g *LightningTerminal) setupFullLNDClient(ctx context.Context,
 				RPCTimeout:            g.cfg.LndRPCTimeout,
 				ChainSyncPollInterval: g.cfg.LndConnectInterval,
 
-				BlockUntilChainSynced:   true,
+				BlockUntilChainSynced:   blockUntilChainSynced,
 				BlockUntilUnlocked:      true,
 				BlockUntilChainNotifier: true,
 			},