Merge pull request #35 from Code-Hex/fix/33

fixed #33

Author: Code-Hex

policy/lfu/lfu.go

@@ -2,6 +2,7 @@ package lfu
 
 import (
 	"container/heap"
+	"log"
 )
 
 // Cache is used a LFU (Least-frequently used) cache replacement policy.
@@ -69,6 +70,8 @@ func (c *Cache[K, V]) Set(key K, val V) {
 
 	if len(c.items) == c.cap {
 		evictedEntry := heap.Pop(c.queue).(*entry[K, V])
+		// e := evictedEntry
+		// log.Println(c.items, e.index, e.key)
 		delete(c.items, evictedEntry.key)
 	}
 
@@ -89,6 +92,7 @@ func (c *Cache[K, V]) Keys() []K {
 // Delete deletes the item with provided key from the cache.
 func (c *Cache[K, V]) Delete(key K) {
 	if e, ok := c.items[key]; ok {
+		log.Println(c.items, e.index, e.key)
 		heap.Remove(c.queue, e.index)
 		delete(c.items, key)
 	}

policy/lfu/lfu_test.go

@@ -44,7 +44,7 @@ func TestSet(t *testing.T) {
 }
 
 func TestDelete(t *testing.T) {
-	cache := lfu.NewCache[string, int](lfu.WithCapacity(1))
+	cache := lfu.NewCache[string, int](lfu.WithCapacity(2))
 	cache.Set("foo", 1)
 	if got := cache.Len(); got != 1 {
 		t.Fatalf("invalid length: %d", got)
@@ -63,3 +63,15 @@ func TestDelete(t *testing.T) {
 		t.Fatalf("invalid get after deleted %v", ok)
 	}
 }
+
+// check don't panic
+func TestIssue33(t *testing.T) {
+	cache := lfu.NewCache[string, int](lfu.WithCapacity(2))
+	cache.Set("foo", 1)
+	cache.Set("foo2", 2)
+	cache.Set("foo3", 3)
+
+	cache.Delete("foo")
+	cache.Delete("foo2")
+	cache.Delete("foo3")
+}

policy/lfu/priotiry_queue.go

@@ -65,7 +65,11 @@ func (l *priorityQueue[K, V]) Pop() interface{} {
 	entry := old[n-1]
 	old[n-1] = nil   // avoid memory leak
 	entry.index = -1 // for safety
-	*l = old[0 : n-1]
+	new := old[0 : n-1]
+	for i := 0; i < len(new); i++ {
+		new[i].index = i
+	}
+	*l = new
 	return entry
 }