cleanup top object list logic in xray

Signed-off-by: Kyle Quest <kcq.public@gmail.com>

Author: kcq

pkg/app/master/command/xray/handler.go

@@ -1090,7 +1090,13 @@ func printImagePackage(
 
 			if len(topList) > 0 {
 				xc.Out.Info("layer.objects.top.start")
-				for _, topObject := range topList {
+				for toi, topObject := range topList {
+					if topObject == nil {
+						log.Errorf("layer.objects.top: skip nil topObject - layer(index=%v/id=%v/path=%s) len(%d) idx(%d)",
+							layer.Index, layer.ID, layer.Path, len(topList), toi)
+						continue
+					}
+
 					match := topObject.PathMatch
 
 					if !match && len(changePathMatchers) > 0 {

pkg/docker/dockerimage/topobjects.go

@@ -26,6 +26,9 @@ func (to TopObjects) Swap(i, j int) {
 
 func (to *TopObjects) Push(x interface{}) {
 	item := x.(*ObjectMetadata)
+	if item == nil {
+		return
+	}
 	*to = append(*to, item)
 }
 
@@ -42,6 +45,9 @@ func (to TopObjects) List() []*ObjectMetadata {
 	list := []*ObjectMetadata{}
 	for len(to) > 0 {
 		item := heap.Pop(&to).(*ObjectMetadata)
+		if item == nil {
+			continue
+		}
 		list = append([]*ObjectMetadata{item}, list...)
 	}