safe truncation

grain-pool.go

@@ -87,12 +87,21 @@ func (p *GrainLocalPool) Purge() {
 		if item.Expires.Before(time.Now()) {
 			if item.Grain.GetLastChange() > keepChanged {
 				log.Printf("Expired item %s changed, keeping", item.Grain.GetId())
-				p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
-				p.expiry = append(p.expiry, item)
+				if i < len(p.expiry)-1 {
+					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
+					p.expiry = append(p.expiry, item)
+				} else {
+					p.expiry = append(p.expiry[:i], item)
+				}
+
 			} else {
 				log.Printf("Item %s expired", item.Grain.GetId())
 				delete(p.grains, item.Grain.GetId())
-				p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
+				if i < len(p.expiry)-1 {
+					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
+				} else {
+					p.expiry = p.expiry[:i]
+				}
 			}
 		} else {
 			break