Add min_final_cltv_expiry parameter to invoice utils

All utility functions for invoice construction will now also accept an
Option<>al `min_final_cltv_expiry_delta` which is useful for things like
swaps etc. The `min_final_cltv_expiry_delta` will default back to
`MIN_FINAL_CLTV_EXPIRY_DELTA` if `None` is provided.

Author: dunxen

lightning-invoice/src/lib.rs

@@ -1448,6 +1448,11 @@ pub enum CreationError {
 	///
 	/// [phantom invoices]: crate::utils::create_phantom_invoice
 	MissingRouteHints,
+
+	/// The provided `min_final_cltv_expiry_delta` was less than [`MIN_FINAL_CLTV_EXPIRY_DELTA`].
+	///
+	/// [`MIN_FINAL_CLTV_EXPIRY_DELTA`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA
+	MinFinalCltvExpiryDeltaTooShort,
 }
 
 impl Display for CreationError {
@@ -1458,6 +1463,8 @@ impl Display for CreationError {
 			CreationError::TimestampOutOfBounds => f.write_str("The Unix timestamp of the supplied date is less than zero or greater than 35-bits"),
 			CreationError::InvalidAmount => f.write_str("The supplied millisatoshi amount was greater than the total bitcoin supply"),
 			CreationError::MissingRouteHints => f.write_str("The invoice required route hints and they weren't provided"),
+			CreationError::MinFinalCltvExpiryDeltaTooShort => f.write_str(
+				"The supplied final CLTV expiry delta was less than LDK's `MIN_FINAL_CLTV_EXPIRY_DELTA`"),
 		}
 	}
 }

lightning-invoice/src/payment.rs

@@ -2081,7 +2081,7 @@ mod tests {
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
 			&nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::Bitcoin,
-			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600, None).unwrap())
 			.is_ok());
 		let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(htlc_msgs.len(), 2);
@@ -2126,7 +2126,7 @@ mod tests {
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
 			&nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::Bitcoin,
-			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600, None).unwrap())
 			.is_ok());
 		let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(htlc_msgs.len(), 2);
@@ -2207,7 +2207,7 @@ mod tests {
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
 			&nodes[1].node, nodes[1].keys_manager, nodes[1].logger, Currency::Bitcoin,
-			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600, None).unwrap())
 			.is_ok());
 		let htlc_updates = SendEvent::from_node(&nodes[0]);
 		check_added_monitors!(nodes[0], 1);