Struct-ify onion util internal result type

Improves readability.

diff --git a/lightning/src/ln/onion_utils.rs b/lightning/src/ln/onion_utils.rs
index c591010ae4dd671a5e5ee42b4b0bb5efb61e8c44..db61f0c90d00530eaf6a6e612ad837d7244beac2 100644 (file)
--- a/lightning/src/ln/onion_utils.rs
+++ b/lightning/src/ln/onion_utils.rs
@@ -444,7 +444,14 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
        } = htlc_source {
                (path, session_priv, first_hop_htlc_msat)
        } else { unreachable!() };
-       let mut res = None;
+
+       // Learnings from the HTLC failure to inform future payment retries and scoring.
+       struct FailureLearnings {
+               network_update: Option<NetworkUpdate>,
+               short_channel_id: Option<u64>,
+               payment_failed_permanently: bool,
+       }
+       let mut res: Option<FailureLearnings> = None;
        let mut htlc_msat = *first_hop_htlc_msat;
        let mut error_code_ret = None;
        let mut error_packet_ret = None;
@@ -507,7 +514,9 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                                        is_permanent: true,
                                });
                                let short_channel_id = Some(route_hop.short_channel_id);
-                               res = Some((network_update, short_channel_id, is_from_final_node));
+                               res = Some(FailureLearnings {
+                                       network_update, short_channel_id, payment_failed_permanently: is_from_final_node
+                               });
                                return
                        }
                };
@@ -659,7 +668,10 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                        short_channel_id = Some(route_hop.short_channel_id);
                }
 
-               res = Some((network_update, short_channel_id, error_code & PERM == PERM && is_from_final_node));
+               res = Some(FailureLearnings {
+                       network_update, short_channel_id,
+                       payment_failed_permanently: error_code & PERM == PERM && is_from_final_node
+               });
 
                let (description, title) = errors::get_onion_error_description(error_code);
                if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
@@ -668,7 +680,9 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
                        log_info!(logger, "Onion Error[from {}: {}({:#x})] {}", route_hop.pubkey, title, error_code, description);
                }
        }).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
-       if let Some((network_update, short_channel_id, payment_failed_permanently)) = res {
+       if let Some(FailureLearnings {
+               network_update, short_channel_id, payment_failed_permanently
+       }) = res {
                DecodedOnionFailure {
                        network_update, short_channel_id, payment_retryable: !payment_failed_permanently,
                        #[cfg(test)]