From 043f78a74f18d80d95e0f6d04f847db29ee8d96a Mon Sep 17 00:00:00 2001
From: "xinyang.nan" <xinyang.nan@shopee.com>
Date: Fri, 15 Apr 2022 18:26:12 +0800
Subject: [PATCH] Fix subtractive overflow

---
 shard.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/shard.go b/shard.go
index 37b09522..ee6ee25e 100644
--- a/shard.go
+++ b/shard.go
@@ -269,7 +269,10 @@ func (s *cacheShard) del(hashedKey uint64) error {
 
 func (s *cacheShard) onEvict(oldestEntry []byte, currentTimestamp uint64, evict func(reason RemoveReason) error) bool {
 	oldestTimestamp := readTimestampFromEntry(oldestEntry)
-	if currentTimestamp-oldestTimestamp > s.lifeWindow {
+	keyHash := readHashFromEntry(oldestEntry)
+	if keyHash == 0 || (currentTimestamp >= oldestTimestamp &&
+		currentTimestamp-oldestTimestamp > s.lifeWindow) {
+
 		evict(Expired)
 		return true
 	}