Fix crash in chanmon_fail_consistency due to fuzz hash collisions

diff --git a/fuzz/fuzz_targets/chanmon_fail_consistency.rs b/fuzz/fuzz_targets/chanmon_fail_consistency.rs
index f457a30913b870e4005628697f2f665519108670..0d966d5d777529881a8ec8505f474515f8a46a3d 100644 (file)
--- a/fuzz/fuzz_targets/chanmon_fail_consistency.rs
+++ b/fuzz/fuzz_targets/chanmon_fail_consistency.rs
@@ -49,6 +49,8 @@ use utils::test_logger;
 use secp256k1::key::{PublicKey,SecretKey};
 use secp256k1::Secp256k1;
 
+use std::cmp::Ordering;
+use std::collections::HashSet;
 use std::sync::{Arc,Mutex};
 use std::io::Cursor;
 
@@ -435,13 +437,36 @@ pub fn do_test(data: &[u8]) {
 
                macro_rules! process_events {
                        ($node: expr, $fail: expr) => { {
-                               for event in nodes[$node].get_and_clear_pending_events() {
+                               // In case we get 256 payments we may have a hash collision, resulting in the
+                               // second claim/fail call not finding the duplicate-hash HTLC, so we have to
+                               // deduplicate the calls here.
+                               let mut claim_set = HashSet::new();
+                               let mut events = nodes[$node].get_and_clear_pending_events();
+                               // Sort events so that PendingHTLCsForwardable get processed last. This avoids a
+                               // case where we first process a PendingHTLCsForwardable, then claim/fail on a
+                               // PaymentReceived, claiming/failing two HTLCs, but leaving a just-generated
+                               // PaymentReceived event for the second HTLC in our pending_events (and breaking
+                               // our claim_set deduplication).
+                               events.sort_by(|a, b| {
+                                       if let events::Event::PaymentReceived { .. } = a {
+                                               if let events::Event::PendingHTLCsForwardable { .. } = b {
+                                                       Ordering::Less
+                                               } else { Ordering::Equal }
+                                       } else if let events::Event::PendingHTLCsForwardable { .. } = a {
+                                               if let events::Event::PaymentReceived { .. } = b {
+                                                       Ordering::Greater
+                                               } else { Ordering::Equal }
+                                       } else { Ordering::Equal }
+                               });
+                               for event in events.drain(..) {
                                        match event {
                                                events::Event::PaymentReceived { payment_hash, .. } => {
-                                                       if $fail {
-                                                               assert!(nodes[$node].fail_htlc_backwards(&payment_hash));
-                                                       } else {
-                                                               assert!(nodes[$node].claim_funds(PaymentPreimage(payment_hash.0)));
+                                                       if claim_set.insert(payment_hash.0) {
+                                                               if $fail {
+                                                                       assert!(nodes[$node].fail_htlc_backwards(&payment_hash));
+                                                               } else {
+                                                                       assert!(nodes[$node].claim_funds(PaymentPreimage(payment_hash.0)));
+                                                               }
                                                        }
                                                },
                                                events::Event::PaymentSent { .. } => {},