Add deferred bool to ChainMonitor

Add a `deferred` parameter to `ChainMonitor::new` and
`ChainMonitor::new_async_beta`. When set to true, the Watch trait
methods (watch_channel and update_channel) will unimplemented!() for
now. All existing callers pass false to preserve current behavior.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: joostjager

fuzz/src/chanmon_consistency.rs

@@ -283,6 +283,7 @@ impl TestChainMonitor {
 				Arc::clone(&persister),
 				Arc::clone(&keys),
 				keys.get_peer_storage_key(),
+				false,
 			)),
 			logger,
 			keys,

fuzz/src/full_stack.rs

@@ -597,6 +597,7 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger>) {
 		Arc::new(TestPersister { update_ret: Mutex::new(ChannelMonitorUpdateStatus::Completed) }),
 		Arc::clone(&keys_manager),
 		keys_manager.get_peer_storage_key(),
+		false,
 	));
 
 	let network = Network::Bitcoin;

fuzz/src/lsps_message.rs

@@ -59,6 +59,7 @@ pub fn do_test(data: &[u8]) {
 		Arc::clone(&kv_store),
 		Arc::clone(&keys_manager),
 		keys_manager.get_peer_storage_key(),
+		false,
 	));
 	let best_block = BestBlock::from_network(network);
 	let params = ChainParameters { network, best_block };

lightning/src/chain/chainmonitor.rs

@@ -371,6 +371,10 @@ pub struct ChainMonitor<
 
 	#[cfg(peer_storage)]
 	our_peerstorage_encryption_key: PeerStorageKey,
+
+	/// When `true`, [`chain::Watch`] operations are queued rather than executed immediately.
+	/// The queued operations can be flushed with [`Self::flush`].
+	deferred: bool,
 }
 
 impl<
@@ -397,7 +401,7 @@ where
 	pub fn new_async_beta(
 		chain_source: Option<C>, broadcaster: T, logger: L, feeest: F,
 		persister: MonitorUpdatingPersisterAsync<K, S, L, ES, SP, T, F>, _entropy_source: ES,
-		_our_peerstorage_encryption_key: PeerStorageKey,
+		_our_peerstorage_encryption_key: PeerStorageKey, deferred: bool,
 	) -> Self {
 		let event_notifier = Arc::new(Notifier::new());
 		Self {
@@ -414,6 +418,7 @@ where
 			pending_send_only_events: Mutex::new(Vec::new()),
 			#[cfg(peer_storage)]
 			our_peerstorage_encryption_key: _our_peerstorage_encryption_key,
+			deferred,
 		}
 	}
 }
@@ -603,7 +608,7 @@ where
 	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
 	pub fn new(
 		chain_source: Option<C>, broadcaster: T, logger: L, feeest: F, persister: P,
-		_entropy_source: ES, _our_peerstorage_encryption_key: PeerStorageKey,
+		_entropy_source: ES, _our_peerstorage_encryption_key: PeerStorageKey, deferred: bool,
 	) -> Self {
 		Self {
 			monitors: RwLock::new(new_hash_map()),
@@ -619,6 +624,7 @@ where
 			pending_send_only_events: Mutex::new(Vec::new()),
 			#[cfg(peer_storage)]
 			our_peerstorage_encryption_key: _our_peerstorage_encryption_key,
+			deferred,
 		}
 	}
 
@@ -1426,12 +1432,18 @@ where
 	fn watch_channel(
 		&self, channel_id: ChannelId, monitor: ChannelMonitor<ChannelSigner>,
 	) -> Result<ChannelMonitorUpdateStatus, ()> {
+		if self.deferred {
+			unimplemented!();
+		}
 		self.watch_channel_internal(channel_id, monitor)
 	}
 
 	fn update_channel(
 		&self, channel_id: ChannelId, update: &ChannelMonitorUpdate,
 	) -> ChannelMonitorUpdateStatus {
+		if self.deferred {
+			unimplemented!();
+		}
 		self.update_channel_internal(channel_id, update)
 	}
 

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -4916,6 +4916,7 @@ fn native_async_persist() {
 		native_async_persister,
 		Arc::clone(&keys_manager),
 		keys_manager.get_peer_storage_key(),
+		false,
 	);
 
 	// Write the initial ChannelMonitor async, testing primarily that the `MonitorEvent::Completed`

lightning/src/ln/channelmanager.rs

@@ -20600,7 +20600,7 @@ pub mod bench {
 
 		let seed_a = [1u8; 32];
 		let keys_manager_a = KeysManager::new(&seed_a, 42, 42, true);
-		let chain_monitor_a = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_a, &keys_manager_a, keys_manager_a.get_peer_storage_key());
+		let chain_monitor_a = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_a, &keys_manager_a, keys_manager_a.get_peer_storage_key(), false);
 		let node_a = ChannelManager::new(&fee_estimator, &chain_monitor_a, &tx_broadcaster, &router, &message_router, &logger_a, &keys_manager_a, &keys_manager_a, &keys_manager_a, config.clone(), ChainParameters {
 			network,
 			best_block: BestBlock::from_network(network),
@@ -20610,7 +20610,7 @@ pub mod bench {
 		let logger_b = test_utils::TestLogger::with_id("node a".to_owned());
 		let seed_b = [2u8; 32];
 		let keys_manager_b = KeysManager::new(&seed_b, 42, 42, true);
-		let chain_monitor_b = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_b, &keys_manager_b, keys_manager_b.get_peer_storage_key());
+		let chain_monitor_b = ChainMonitor::new(None, &tx_broadcaster, &logger_a, &fee_estimator, &persister_b, &keys_manager_b, keys_manager_b.get_peer_storage_key(), false);
 		let node_b = ChannelManager::new(&fee_estimator, &chain_monitor_b, &tx_broadcaster, &router, &message_router, &logger_b, &keys_manager_b, &keys_manager_b, &keys_manager_b, config.clone(), ChainParameters {
 			network,
 			best_block: BestBlock::from_network(network),

lightning/src/util/test_utils.rs

@@ -537,6 +537,7 @@ impl<'a> TestChainMonitor<'a> {
 				persister,
 				keys_manager,
 				keys_manager.get_peer_storage_key(),
+				false,
 			),
 			keys_manager,
 			expect_channel_force_closed: Mutex::new(None),