Document ChannelPending temporary id invariant

Replace the pending-channel unwrap with an expect that records why supported LDK Node state should always include the former temporary channel id. Older rust-lightning state could omit it, but LDK Node never shipped before that field existed.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

Author: tnull

src/event.rs

@@ -1452,11 +1452,14 @@ where
 					counterparty_node_id,
 				);
 
+				let former_temporary_channel_id = former_temporary_channel_id.expect(
+					"LDK Node has only ever persisted ChannelPending events from rust-lightning 0.0.115 or later",
+				);
+
 				let event = Event::ChannelPending {
 					channel_id,
 					user_channel_id: UserChannelId(user_channel_id),
-					former_temporary_channel_id: former_temporary_channel_id
-						.expect("former temporary channel id should be set"),
+					former_temporary_channel_id,
 					counterparty_node_id,
 					funding_txo,
 				};

src/types.rs

@@ -565,7 +565,6 @@ pub struct ChannelDetails {
 }
 
 impl From<LdkChannelDetails> for ChannelDetails {
-	#[allow(clippy::unwrap_used)]
 	fn from(value: LdkChannelDetails) -> Self {
 		ChannelDetails {
 			channel_id: value.channel_id,
@@ -578,9 +577,9 @@ impl From<LdkChannelDetails> for ChannelDetails {
 			channel_value_sats: value.channel_value_satoshis,
 			unspendable_punishment_reserve: value.unspendable_punishment_reserve,
 			user_channel_id: UserChannelId(value.user_channel_id),
-			// unwrap safety: This value will be `None` for objects serialized with LDK versions
-			// prior to 0.0.115.
-			feerate_sat_per_1000_weight: value.feerate_sat_per_1000_weight.unwrap(),
+			feerate_sat_per_1000_weight: value
+				.feerate_sat_per_1000_weight
+				.expect("value is set for objects serialized with LDK v0.0.115+"),
 			outbound_capacity_msat: value.outbound_capacity_msat,
 			inbound_capacity_msat: value.inbound_capacity_msat,
 			confirmations_required: value.confirmations_required,
@@ -613,11 +612,14 @@ impl From<LdkChannelDetails> for ChannelDetails {
 			next_outbound_htlc_limit_msat: value.next_outbound_htlc_limit_msat,
 			next_outbound_htlc_minimum_msat: value.next_outbound_htlc_minimum_msat,
 			force_close_spend_delay: value.force_close_spend_delay,
-			// unwrap safety: This field is only `None` for objects serialized prior to LDK 0.0.107
-			inbound_htlc_minimum_msat: value.inbound_htlc_minimum_msat.unwrap_or(0),
+			inbound_htlc_minimum_msat: value
+				.inbound_htlc_minimum_msat
+				.expect("value is set for objects serialized with LDK v0.0.107+"),
 			inbound_htlc_maximum_msat: value.inbound_htlc_maximum_msat,
-			// unwrap safety: `config` is only `None` for LDK objects serialized prior to 0.0.109.
-			config: value.config.map(|c| c.into()).unwrap(),
+			config: value
+				.config
+				.map(|c| c.into())
+				.expect("value is set for objects serialized with LDK v0.0.109+"),
 			channel_shutdown_state: value.channel_shutdown_state,
 		}
 	}