Make Event::PersistClaimInfo optional

While downstream code can always ignore `Event::PersistClaimInfo`,
the generation of them can be somewhat expensive, so we thus allow
downstream logic to disable them entirely here.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: TheBlueMatt

fuzz/src/chanmon_consistency.rs

@@ -282,6 +282,7 @@ impl TestChainMonitor {
 				Arc::clone(&persister),
 				Arc::clone(&keys),
 				keys.get_peer_storage_key(),
+				false,
 			)),
 			logger,
 			keys,

fuzz/src/full_stack.rs

@@ -603,6 +603,7 @@ pub fn do_test(mut data: &[u8], logger: &Arc<dyn Logger + MaybeSend + MaybeSync>
 		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-background-processor/src/lib.rs

@@ -2444,6 +2444,7 @@ mod tests {
 				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-persister/src/fs_store/v1.rs

@@ -217,6 +217,7 @@ mod tests {
 			&chanmon_cfgs[0].fee_estimator,
 			&store,
 			node_cfgs[0].keys_manager,
+			false,
 		);
 		node_cfgs[0].chain_monitor = chain_mon_0;
 		let node_chanmgrs = create_node_chanmgrs(1, &node_cfgs, &[None]);

lightning-persister/src/test_utils.rs

@@ -120,6 +120,7 @@ pub(crate) fn do_test_store<K: KVStoreSync + Sync>(store_0: &K, store_1: &K) {
 		&chanmon_cfgs[0].fee_estimator,
 		store_0,
 		node_cfgs[0].keys_manager,
+		false,
 	);
 	let chain_mon_1 = test_utils::TestChainMonitor::new(
 		Some(&chanmon_cfgs[1].chain_source),
@@ -128,6 +129,7 @@ pub(crate) fn do_test_store<K: KVStoreSync + Sync>(store_0: &K, store_1: &K) {
 		&chanmon_cfgs[1].fee_estimator,
 		store_1,
 		node_cfgs[1].keys_manager,
+		false,
 	);
 	node_cfgs[0].chain_monitor = chain_mon_0;
 	node_cfgs[1].chain_monitor = chain_mon_1;

lightning/src/chain/chainmonitor.rs

@@ -371,6 +371,9 @@ pub struct ChainMonitor<
 
 	#[cfg(peer_storage)]
 	our_peerstorage_encryption_key: PeerStorageKey,
+
+	/// If false, claim info persistence events are swallowed.
+	offload_claim_info: bool,
 }
 
 impl<
@@ -397,7 +400,7 @@ 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, offload_claim_info: bool,
 	) -> Self {
 		let event_notifier = Arc::new(Notifier::new());
 		Self {
@@ -414,6 +417,7 @@ where
 			pending_send_only_events: Mutex::new(Vec::new()),
 			#[cfg(peer_storage)]
 			our_peerstorage_encryption_key: _our_peerstorage_encryption_key,
+			offload_claim_info,
 		}
 	}
 }
@@ -590,6 +594,15 @@ where
 	/// always need to fetch full blocks absent another means for determining which blocks contain
 	/// transactions relevant to the watched channels.
 	///
+	/// If `offload_claim_info` is set to `true`, [`Event::PersistClaimInfo`] events will be
+	/// surfaced, allowing callers to offload claim information from [`ChannelMonitor`]s to reduce
+	/// their size. If set to `false`, these events will be silently ignored and the claim
+	/// information will remain in-memory and in each [`ChannelMonitor`] on disk.
+	///
+	/// Note that no matter the value of `offload_claim_info`, [`Event::ClaimInfoRequest`]s will be
+	/// surfaced if needed. If [`Event::PersistClaimInfo`]s have never been surfaced/handled for a
+	/// node, no [`Event::ClaimInfoRequest`] will be generated.
+	///
 	/// # Note
 	/// `our_peerstorage_encryption_key` must be obtained from [`NodeSigner::get_peer_storage_key`].
 	/// This key is used to encrypt peer storage backups.
@@ -601,9 +614,12 @@ where
 	/// [`NodeSigner`]: crate::sign::NodeSigner
 	/// [`NodeSigner::get_peer_storage_key`]: crate::sign::NodeSigner::get_peer_storage_key
 	/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+	/// [`Event::PersistClaimInfo`]: crate::events::Event::PersistClaimInfo
+	/// [`Event::ClaimInfoRequest`]: crate::events::Event::ClaimInfoRequest
 	pub fn new(
 		chain_source: Option<C>, broadcaster: T, logger: L, feeest: F, persister: P,
 		_entropy_source: ES, _our_peerstorage_encryption_key: PeerStorageKey,
+		offload_claim_info: bool,
 	) -> Self {
 		Self {
 			monitors: RwLock::new(new_hash_map()),
@@ -619,6 +635,7 @@ where
 			pending_send_only_events: Mutex::new(Vec::new()),
 			#[cfg(peer_storage)]
 			our_peerstorage_encryption_key: _our_peerstorage_encryption_key,
+			offload_claim_info,
 		}
 	}
 
@@ -880,7 +897,17 @@ where
 				self.monitors.read().unwrap().get(&channel_id).map(|m| &m.monitor),
 				self.logger,
 				ev,
-				handler(ev).await
+				{
+					if !self.offload_claim_info {
+						if let Event::PersistClaimInfo { .. } = &ev {
+							Ok(())
+						} else {
+							handler(ev).await
+						}
+					} else {
+						handler(ev).await
+					}
+				}
 			) {
 				Ok(()) => {},
 				Err(ReplayEvent()) => {
@@ -1539,8 +1566,16 @@ where
 	where
 		H::Target: EventHandler,
 	{
+		let filtering_handler = |event: events::Event| {
+			if !self.offload_claim_info {
+				if let events::Event::PersistClaimInfo { .. } = &event {
+					return Ok(());
+				}
+			}
+			handler.handle_event(event)
+		};
 		for monitor_state in self.monitors.read().unwrap().values() {
-			match monitor_state.monitor.process_pending_events(&handler, &self.logger) {
+			match monitor_state.monitor.process_pending_events(&&filtering_handler, &self.logger) {
 				Ok(()) => {},
 				Err(ReplayEvent()) => {
 					self.event_notifier.notify();

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -108,6 +108,7 @@ fn test_monitor_and_persister_update_fail() {
 			&chanmon_cfgs[0].fee_estimator,
 			&persister,
 			&node_cfgs[0].keys_manager,
+			false,
 		);
 		assert_eq!(
 			chain_mon.watch_channel(chan.2, new_monitor),
@@ -4931,6 +4932,7 @@ 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

@@ -21259,7 +21259,7 @@ 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),
@@ -21269,7 +21269,7 @@ 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/ln/functional_test_utils.rs

@@ -929,6 +929,7 @@ impl<'a, 'b, 'c> Drop for Node<'a, 'b, 'c> {
 				&feeest,
 				&persister,
 				&self.keys_manager,
+				false,
 			);
 			for deserialized_monitor in deserialized_monitors.drain(..) {
 				let channel_id = deserialized_monitor.channel_id();
@@ -1444,6 +1445,7 @@ macro_rules! _reload_node_inner {
 			$node.fee_estimator,
 			&$persister,
 			&$node.keys_manager,
+			false,
 		);
 		$node.chain_monitor = &$new_chain_monitor;
 
@@ -4644,6 +4646,7 @@ where
 			&cfg.fee_estimator,
 			persisters[i],
 			&cfg.keys_manager,
+			false,
 		);
 
 		let seed = [i as u8; 32];