Merge pull request #80648 from odinuge/kubeadm-upgrade-diff-err

Fix error handling issue in kubeadm upgrade diff

cmd/kubeadm/app/cmd/upgrade/diff.go

@@ -25,6 +25,7 @@ import (
 	"github.com/spf13/cobra"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/version"
+	client "k8s.io/client-go/kubernetes"
 	"k8s.io/klog"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
@@ -86,7 +87,8 @@ func runDiff(flags *diffFlags, args []string) error {
 	if flags.cfgPath != "" {
 		cfg, err = configutil.LoadInitConfigurationFromFile(flags.cfgPath)
 	} else {
-		client, err := kubeconfigutil.ClientSetFromFile(flags.kubeConfigPath)
+		var client *client.Clientset
+		client, err = kubeconfigutil.ClientSetFromFile(flags.kubeConfigPath)
 		if err != nil {
 			return errors.Wrapf(err, "couldn't create a Kubernetes client from file %q", flags.kubeConfigPath)
 		}