CHANGELOG.md (1)

42-43: Clarify scope and casing of “Drand”; tighten phrasing.

Make it explicit this affects unchained Drand (Quicknet) beacons typically used by new devnets, and use consistent “Drand” casing.

Apply this diff:

-- [#5055](https://github.com/ChainSafe/forest/issues/5055) Fixed an issue where Forest fails on duplicate drand entries. This would only happen on new devnets.
+- [#5055](https://github.com/ChainSafe/forest/issues/5055) Fixed a failure on duplicate Drand entries for unchained beacons (Quicknet), typically affecting new devnets.

src/beacon/drand.rs (1)

292-301: Good fix: deduping unchained rounds prevents batch-verify pitfalls on duplicates.

This addresses the duplicate-rounds failure. Optional micro-optimization: since entries are documented as “sorted by round,” you can avoid a HashSet allocation in unique_by and skip contiguous dups in O(1) extra space.

Apply this diff:

-                // Deduplicate by round. See Lotus issue: https://github.com/filecoin-project/lotus/issues/13349
-                for entry in entries.iter().unique_by(|e| e.round()) {
-                    if self.is_verified(entry) {
-                        continue;
-                    }
-
-                    messages.push(BeaconEntry::message_unchained(entry.round()));
-                    signatures.push(SignatureOnG1::from_bytes(entry.signature())?);
-                    validated.push(entry);
-                }
+                // Deduplicate contiguous duplicates (entries are sorted by round).
+                let mut last_round: Option<u64> = None;
+                for entry in entries {
+                    let r = entry.round();
+                    if last_round == Some(r) || self.is_verified(entry) {
+                        continue;
+                    }
+                    last_round = Some(r);
+
+                    messages.push(BeaconEntry::message_unchained(r));
+                    signatures.push(SignatureOnG1::from_bytes(entry.signature())?);
+                    validated.push(entry);
+                }

If you prefer to retain unique_by for non-contiguous dups, consider a quick early return when messages.is_empty() to skip a no-op verify_batch. I can also add a unit test that feeds duplicated unchained entries and asserts verify_entries returns true and caches once—say, drand::tests::verify_entries_unchained_dedups_duplicates. Want me to draft it?

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

Learnt from: LesnyRumcajs
PR: ChainSafe/forest#5907
File: src/rpc/methods/state.rs:523-570
Timestamp: 2025-08-06T15:44:33.467Z
Learning: LesnyRumcajs prefers to rely on BufWriter's Drop implementation for automatic flushing rather than explicit flush() calls in Forest codebase.