minikube upate-cotext: Fix nil pointer dereference

go.mod

@@ -72,7 +72,6 @@ require (
 	github.com/zchee/go-vmnet v0.0.0-20161021174912-97ebf9174097
 	golang.org/x/build v0.0.0-20190927031335-2835ba2e683f
 	golang.org/x/crypto v0.0.0-20200510223506-06a226fb4e37
-	golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6 // indirect
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a
 	golang.org/x/sys v0.0.0-20200523222454-059865788121

pkg/minikube/kubeconfig/kubeconfig.go

@@ -21,7 +21,6 @@ import (
 	"io/ioutil"
 	"net/url"
 	"os"
-	"path"
 	"path/filepath"
 	"strconv"
 
@@ -31,7 +30,6 @@ import (
 	"k8s.io/client-go/tools/clientcmd/api"
 	"k8s.io/client-go/tools/clientcmd/api/latest"
 	"k8s.io/minikube/pkg/minikube/constants"
-	"k8s.io/minikube/pkg/minikube/localpath"
 	pkgutil "k8s.io/minikube/pkg/util"
 	"k8s.io/minikube/pkg/util/lock"
 )
@@ -121,26 +119,11 @@ func UpdateEndpoint(contextName string, hostname string, port int, confpath stri
 		return false, errors.Wrap(err, "read")
 	}
 
-	address := "https://" + hostname + ":" + strconv.Itoa(port)
-
-	// if the kubeconfig is missed, create new one
-	if len(cfg.Clusters) == 0 {
-		lp := localpath.Profile(contextName)
-		gp := localpath.MiniPath()
-		kcs := &Settings{
-			ClusterName:          contextName,
-			ClusterServerAddress: address,
-			ClientCertificate:    path.Join(lp, "client.crt"),
-			ClientKey:            path.Join(lp, "client.key"),
-			CertificateAuthority: path.Join(gp, "ca.crt"),
-			KeepContext:          false,
-		}
-		err = PopulateFromSettings(kcs, cfg)
-		if err != nil {
-			return false, errors.Wrap(err, "populating kubeconfig")
-		}
+	if _, ok := cfg.Clusters[contextName]; !ok {
+		return false, errors.Errorf("%q does not appear in %s", contextName, confpath)
 	}
-	cfg.Clusters[contextName].Server = address
+
+	cfg.Clusters[contextName].Server = "https://" + hostname + ":" + strconv.Itoa(port)
 	err = writeToFile(cfg, confpath)
 	if err != nil {
 		return false, errors.Wrap(err, "write")

pkg/minikube/kubeconfig/kubeconfig_test.go

@@ -343,6 +343,18 @@ func TestUpdateIP(t *testing.T) {
 			if test.status != statusActual {
 				t.Errorf("Expected status %t, but got %t", test.status, statusActual)
 			}
+
+			actual, err := readOrNew(configFilename)
+			if err != nil {
+				t.Fatal(err)
+			}
+			expected, err := decode(test.expCfg)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !configEquals(actual, expected) {
+				t.Errorf("Expected cfg %v, but got %v", expected, actual)
+			}
 		})
 
 	}