Merge pull request kubernetes#45658 from zhangxiaoyu-zidif/add-strong-to-parsepodfulname

Automatic merge from submit-queue (batch tested with PRs 41331, 45591, 45600, 45176, 45658)

ParsePodFullName():code robustness

**What this PR does / why we need it**:

ParsePodFullName():code robustness

if pod name or namespace name is null, the function can handle it.
Meanwhile update unit test 

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

Author: Kubernetes Submit Queue

pkg/kubelet/container/runtime.go

@@ -608,7 +608,7 @@ func BuildPodFullName(name, namespace string) string {
 // Parse the pod full name.
 func ParsePodFullName(podFullName string) (string, string, error) {
 	parts := strings.Split(podFullName, "_")
-	if len(parts) != 2 {
+	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
 		return "", "", fmt.Errorf("failed to parse the pod full name %q", podFullName)
 	}
 	return parts[0], parts[1], nil

pkg/kubelet/pod/mirror_client_test.go

@@ -32,7 +32,7 @@ func TestParsePodFullName(t *testing.T) {
 		"bar.org_foo.com": {Name: "bar.org", Namespace: "foo.com"},
 		"bar-bar_foo":     {Name: "bar-bar", Namespace: "foo"},
 	}
-	failedCases := []string{"barfoo", "bar_foo_foo", ""}
+	failedCases := []string{"barfoo", "bar_foo_foo", "", "bar_", "_foo"}
 
 	for podFullName, expected := range successfulCases {
 		name, namespace, err := kubecontainer.ParsePodFullName(podFullName)