f - Assert unannounced-channel default stays at 100%

Per review feedback on PR #878. The forwarding behavior for LSPS2 channels
relies on LDK's default of 100% for the unannounced-channel inbound
HTLC value-in-flight cap. Catch upstream changes to that default with
debug asserts at the three sites that depend on it.

Generated with assistance from Claude Code.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jkczyz

src/event.rs

@@ -1278,6 +1278,17 @@ where
 							}),
 							..Default::default()
 						});
+
+						// LSPS2 channels are unannounced; rely on LDK's default of 100%
+						// inbound HTLC value-in-flight so the LSP can forward the initial
+						// payment in full.
+						debug_assert_eq!(
+							self.channel_manager
+								.get_current_config()
+								.channel_handshake_config
+								.unannounced_channel_max_inbound_htlc_value_in_flight_percentage,
+							100
+						);
 					}
 				}
 				let res = if allow_0conf {

src/lib.rs

@@ -1196,6 +1196,17 @@ impl Node {
 		user_config.channel_handshake_config.announce_for_forwarding = announce_for_forwarding;
 		user_config.channel_config = (channel_config.unwrap_or_default()).clone().into();
 
+		// Unannounced channels rely on LDK's default of 100% inbound HTLC value-in-flight
+		// to support large initial payments via LSPS2.
+		if !announce_for_forwarding {
+			debug_assert_eq!(
+				user_config
+					.channel_handshake_config
+					.unannounced_channel_max_inbound_htlc_value_in_flight_percentage,
+				100
+			);
+		}
+
 		let push_msat = push_to_counterparty_msat.unwrap_or(0);
 		let user_channel_id: u128 = u128::from_ne_bytes(
 			self.keys_manager.get_secure_random_bytes()[..16]

src/liquidity.rs

@@ -782,13 +782,15 @@ where
 				let mut config = self.channel_manager.get_current_config().clone();
 
 				// If we act as an LSPS2 service, the HTLC-value-in-flight must be 100% of the
-				// channel value to ensure we can forward the initial payment.
+				// channel value to ensure we can forward the initial payment. That cap only
+				// applies to unannounced channels, so the channel must also be unannounced.
 				debug_assert_eq!(
 					config
 						.channel_handshake_config
 						.unannounced_channel_max_inbound_htlc_value_in_flight_percentage,
 					100
 				);
+				debug_assert!(!config.channel_handshake_config.announce_for_forwarding);
 				debug_assert!(config.accept_forwards_to_priv_channels);
 
 				// We set the forwarding fee to 0 for now as we're getting paid by the channel fee.