Fix expired in get

cache_test.go

@@ -488,3 +488,25 @@ func (h *optimalHeap) Pop() any {
 	*h = old[0 : n-1]
 	return x
 }
+
+func Test_GetExpired(t *testing.T) {
+	c, err := MustBuilder[string, string](1000000).
+		CollectStats().
+		DeletionListener(func(key string, value string, cause DeletionCause) {
+			fmt.Println(cause)
+			if cause != Expired {
+				t.Fatalf("err not expired: %v", cause)
+			}
+		}).
+		WithVariableTTL().
+		Build()
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.Set("test1", "123456", time.Duration(12)*time.Second)
+	for i := 0; i < 5; i++ {
+		c.Get("test1")
+		time.Sleep(3 * time.Second)
+	}
+	time.Sleep(1 * time.Second)
+}

internal/core/cache.go

@@ -219,7 +219,8 @@ func (c *Cache[K, V]) GetNode(key K) (node.Node[K, V], bool) {
 	}
 
 	if n.HasExpired() {
-		c.writeBuffer.Push(newDeleteTask(n))
+		n.Die()
+		c.writeBuffer.Push(newExpiredTask(n))
 		c.stats.IncMisses()
 		return nil, false
 	}
@@ -437,6 +438,10 @@ func (c *Cache[K, V]) onWrite(t task[K, V]) {
 		c.expiryPolicy.Delete(n)
 		c.policy.Delete(n)
 		c.notifyDeletion(n.Key(), n.Value(), Explicit)
+	case t.isExpired():
+		c.expiryPolicy.Delete(n)
+		c.policy.Delete(n)
+		c.notifyDeletion(n.Key(), n.Value(), Expired)
 	}
 }
 

internal/core/task.go

@@ -27,6 +27,7 @@ const (
 	updateReason
 	clearReason
 	closeReason
+	expiredReason
 )
 
 // task is a set of information to update the cache:
@@ -53,6 +54,14 @@ func newDeleteTask[K comparable, V any](n node.Node[K, V]) task[K, V] {
 	}
 }
 
+// newExpireTask creates a task to delete a expired node from policies.
+func newExpiredTask[K comparable, V any](n node.Node[K, V]) task[K, V] {
+	return task[K, V]{
+		n:           n,
+		writeReason: expiredReason,
+	}
+}
+
 // newUpdateTask creates a task to update the node in the policies.
 func newUpdateTask[K comparable, V any](n, oldNode node.Node[K, V]) task[K, V] {
 	return task[K, V]{
@@ -96,6 +105,11 @@ func (t *task[K, V]) isDelete() bool {
 	return t.writeReason == deleteReason
 }
 
+// isExpired returns true if this is an expired task.
+func (t *task[K, V]) isExpired() bool {
+	return t.writeReason == expiredReason
+}
+
 // isUpdate returns true if this is an update task.
 func (t *task[K, V]) isUpdate() bool {
 	return t.writeReason == updateReason