nats-io/nats-server · error

AppendEntry failed to be placed on internal channel: corrupt

Error message

AppendEntry failed to be placed on internal channel: corrupt entry

What it means

handleAppendEntry's decodeAppendEntry failed to decode the wire message into a valid append entry (truncated or malformed payload), so the entry is not placed on the internal entry channel. The replication message is dropped; correctness is preserved because the leader retries unacknowledged entries.

Source

Thrown at server/raft.go:4245

			// Because of drain() it is possible that we get nil from popOne().
			if voteReq, ok := n.reqs.popOne(); ok {
				n.processVoteRequest(voteReq)
			}
		}
	}
}

// handleAppendEntry handles an append entry from the wire. This function
// is an internal callback from the "asubj" append entry subscription.
func (n *raft) handleAppendEntry(sub *subscription, c *client, _ *Account, _, reply string, msg []byte) {
	msg = copyBytes(msg)
	if ae, err := decodeAppendEntry(msg, sub, reply); err == nil {
		// Push to the new entry channel. From here one of the worker
		// goroutines (runAsLeader, runAsFollower, runAsCandidate) will
		// pick it up.
		n.entry.push(ae)
	} else {
		n.warn("AppendEntry failed to be placed on internal channel: corrupt entry")
	}
}

// cancelCatchup will stop an in-flight catchup by unsubscribing from the
// catchup subscription.
// Lock should be held.
func (n *raft) cancelCatchup() {
	n.debug("Canceling catchup subscription since we are now up to date")

	if n.catchup != nil && n.catchup.sub != nil {
		n.unsubscribe(n.catchup.sub)
	}
	n.cancelCatchupSignal()
	n.catchup = nil
}

// catchupStalled will try to determine if we are stalled. This is called
// on a new entry from our leader.

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Check for cluster version mismatches changing the wire format
2. Look for message corruption on the internal transport (MTU/network issues)
3. Leader heartbeats/retries will recover; investigate if a follower persistently fails

When it happens

Trigger: Thrown at server/raft.go:4245 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/4530b8a07c6ac05e. Report an issue: GitHub.