fix(cbf): stamp sync timestamps even when no scripts are registered

Both sync_onchain_wallet and sync_lightning_wallet returned Ok(())
early when there were no registered scripts, *before* reaching the
update_node_metrics_timestamp call. As a result, on-chain-only nodes
(no Lightning channels) never advanced latest_lightning_wallet_sync_
timestamp, and any caller treating that timestamp as a "sync ran"
signal would observe a permanent stall.

This is the root cause behind the wait_for_cbf_sync helper timing out
in CI for every test that doesn't open a Lightning channel
(fee_rate_estimation_after_manual_sync_cbf, onchain_send_receive_cbf,
onchain_wallet_recovery_cbf, repeated_manual_sync_cbf,
start_stop_reinit_cbf). The helper requires both onchain and lightning
timestamps to advance, and the lightning side could never advance for
those nodes.

Other chain sources (electrum, bitcoind) already stamp the lightning
sync timestamp unconditionally on success, so this brings CBF in line
with them: an empty-scripts call is treated as a successful no-op
sync, the actual filter scan is still correctly skipped, and the
requester() precondition check remains in place to ensure we never
mark a sync as successful while the chain source isn't running.

Reviewed by Codex (gpt-5.4).
AI-assisted with Claude Code.

Author: febyeji

src/chain/cbf.rs

@@ -586,53 +586,52 @@ impl CbfChainSource {
 
 		let res = async {
 			let requester = self.requester()?;
-			let now = Instant::now();
 
 			let scripts = onchain_wallet.get_spks_for_cbf_sync(BDK_CLIENT_STOP_GAP);
 			if scripts.is_empty() {
 				log_debug!(self.logger, "No wallet scripts to sync via CBF.");
-				return Ok(());
-			}
-
-			let timeout_fut = tokio::time::timeout(
-				Duration::from_secs(
-					self.sync_config.timeouts_config.onchain_wallet_sync_timeout_secs,
-				),
-				self.sync_onchain_wallet_op(requester, &onchain_wallet, scripts),
-			);
+			} else {
+				let now = Instant::now();
+				let timeout_fut = tokio::time::timeout(
+					Duration::from_secs(
+						self.sync_config.timeouts_config.onchain_wallet_sync_timeout_secs,
+					),
+					self.sync_onchain_wallet_op(requester, &onchain_wallet, scripts),
+				);
 
-			let (tx_update, sync_update) = match timeout_fut.await {
-				Ok(res) => res?,
-				Err(e) => {
-					log_error!(self.logger, "Sync of on-chain wallet timed out: {}", e);
-					return Err(Error::WalletOperationTimeout);
-				},
-			};
+				let (tx_update, sync_update) = match timeout_fut.await {
+					Ok(res) => res?,
+					Err(e) => {
+						log_error!(self.logger, "Sync of on-chain wallet timed out: {}", e);
+						return Err(Error::WalletOperationTimeout);
+					},
+				};
 
-			// Build chain checkpoint extending from the wallet's current tip.
-			let mut cp = onchain_wallet.latest_checkpoint();
-			for (height, header) in sync_update.recent_history() {
-				if *height > cp.height() {
-					let block_id = BlockId { height: *height, hash: header.block_hash() };
-					cp = cp.push(block_id).unwrap_or_else(|old| old);
+				// Build chain checkpoint extending from the wallet's current tip.
+				let mut cp = onchain_wallet.latest_checkpoint();
+				for (height, header) in sync_update.recent_history() {
+					if *height > cp.height() {
+						let block_id = BlockId { height: *height, hash: header.block_hash() };
+						cp = cp.push(block_id).unwrap_or_else(|old| old);
+					}
+				}
+				let tip = sync_update.tip();
+				if tip.height > cp.height() {
+					let tip_block_id = BlockId { height: tip.height, hash: tip.hash };
+					cp = cp.push(tip_block_id).unwrap_or_else(|old| old);
 				}
-			}
-			let tip = sync_update.tip();
-			if tip.height > cp.height() {
-				let tip_block_id = BlockId { height: tip.height, hash: tip.hash };
-				cp = cp.push(tip_block_id).unwrap_or_else(|old| old);
-			}
 
-			let update =
-				Update { last_active_indices: BTreeMap::new(), tx_update, chain: Some(cp) };
+				let update =
+					Update { last_active_indices: BTreeMap::new(), tx_update, chain: Some(cp) };
 
-			onchain_wallet.apply_update(update)?;
+				onchain_wallet.apply_update(update)?;
 
-			log_debug!(
-				self.logger,
-				"Sync of on-chain wallet via CBF finished in {}ms.",
-				now.elapsed().as_millis()
-			);
+				log_debug!(
+					self.logger,
+					"Sync of on-chain wallet via CBF finished in {}ms.",
+					now.elapsed().as_millis()
+				);
+			}
 
 			update_node_metrics_timestamp(
 				&self.node_metrics,
@@ -733,40 +732,39 @@ impl CbfChainSource {
 
 		let res = async {
 			let requester = self.requester()?;
-			let now = Instant::now();
 
 			let scripts: Vec<ScriptBuf> = self.registered_scripts.lock().unwrap().clone();
 			if scripts.is_empty() {
 				log_debug!(self.logger, "No registered scripts for CBF lightning sync.");
-				return Ok(());
-			}
-
-			let timeout_fut = tokio::time::timeout(
-				Duration::from_secs(
-					self.sync_config.timeouts_config.lightning_wallet_sync_timeout_secs,
-				),
-				self.sync_lightning_wallet_op(
-					requester,
-					channel_manager,
-					chain_monitor,
-					output_sweeper,
-					scripts,
-				),
-			);
+			} else {
+				let now = Instant::now();
+				let timeout_fut = tokio::time::timeout(
+					Duration::from_secs(
+						self.sync_config.timeouts_config.lightning_wallet_sync_timeout_secs,
+					),
+					self.sync_lightning_wallet_op(
+						requester,
+						channel_manager,
+						chain_monitor,
+						output_sweeper,
+						scripts,
+					),
+				);
 
-			match timeout_fut.await {
-				Ok(res) => res?,
-				Err(e) => {
-					log_error!(self.logger, "Sync of Lightning wallet timed out: {}", e);
-					return Err(Error::TxSyncTimeout);
-				},
-			};
+				match timeout_fut.await {
+					Ok(res) => res?,
+					Err(e) => {
+						log_error!(self.logger, "Sync of Lightning wallet timed out: {}", e);
+						return Err(Error::TxSyncTimeout);
+					},
+				};
 
-			log_debug!(
-				self.logger,
-				"Sync of Lightning wallet via CBF finished in {}ms.",
-				now.elapsed().as_millis()
-			);
+				log_debug!(
+					self.logger,
+					"Sync of Lightning wallet via CBF finished in {}ms.",
+					now.elapsed().as_millis()
+				);
+			}
 
 			update_node_metrics_timestamp(
 				&self.node_metrics,