fix: skip fzf launch in kubens when no contexts exist in kubeconfig (#481)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

cmd/kubectx/fzf.go

@@ -52,6 +52,14 @@ func (op InteractiveSwitchOp) Run(_, stderr io.Writer) error {
 		return fmt.Errorf("kubeconfig error: %w", err)
 	}
 
+	ctxNames, err := kc.ContextNames()
+	if err != nil {
+		return fmt.Errorf("failed to get context names: %w", err)
+	}
+	if len(ctxNames) == 0 {
+		return errors.New("no contexts found in the kubeconfig file")
+	}
+
 	cmd := exec.Command("fzf", "--ansi", "--no-preview")
 	var out bytes.Buffer
 	cmd.Stdin = os.Stdin

cmd/kubens/fzf.go

@@ -46,6 +46,14 @@ func (op InteractiveSwitchOp) Run(_, stderr io.Writer) error {
 		return fmt.Errorf("kubeconfig error: %w", err)
 	}
 
+	ctxNames, err := kc.ContextNames()
+	if err != nil {
+		return fmt.Errorf("failed to get context names: %w", err)
+	}
+	if len(ctxNames) == 0 {
+		return errors.New("no contexts found in the kubeconfig file")
+	}
+
 	cmd := exec.Command("fzf", "--ansi", "--no-preview")
 	var out bytes.Buffer
 	cmd.Stdin = os.Stdin

cmd/kubens/statefile_test.go

@@ -18,8 +18,6 @@ import (
 	"runtime"
 	"strings"
 	"testing"
-
-	"github.com/ahmetb/kubectx/internal/testutil"
 )
 
 func TestNSFile(t *testing.T) {
@@ -50,7 +48,7 @@ func TestNSFile(t *testing.T) {
 }
 
 func TestNSFile_path_windows(t *testing.T) {
-	defer testutil.WithEnvVar("_FORCE_GOOS", "windows")()
+	t.Setenv("_FORCE_GOOS", "windows")
 	fp := NewNSFile("a:b:c").path()
 
 	if expected := "a__b__c"; !strings.HasSuffix(fp, expected) {
@@ -68,7 +66,7 @@ func Test_isWindows(t *testing.T) {
 		t.Fatalf("isWindows() returned true for %s", runtime.GOOS)
 	}
 
-	defer testutil.WithEnvVar("_FORCE_GOOS", "windows")()
+	t.Setenv("_FORCE_GOOS", "windows")
 	if !isWindows() {
 		t.Fatalf("isWindows() failed to detect windows with env override.")
 	}

internal/cmdutil/util_test.go

@@ -17,8 +17,6 @@ package cmdutil
 import (
 	"path/filepath"
 	"testing"
-
-	"github.com/ahmetb/kubectx/internal/testutil"
 )
 
 func Test_homeDir(t *testing.T) {
@@ -64,18 +62,14 @@ func Test_homeDir(t *testing.T) {
 
 	for _, c := range cases {
 		t.Run(c.name, func(tt *testing.T) {
-			var unsets []func()
 			for _, e := range c.envs {
-				unsets = append(unsets, testutil.WithEnvVar(e.k, e.v))
+				tt.Setenv(e.k, e.v)
 			}
 
 			got := HomeDir()
 			if got != c.want {
 				t.Errorf("expected:%q got:%q", c.want, got)
 			}
-			for _, u := range unsets {
-				u()
-			}
 		})
 	}
 }

internal/kubeconfig/kubeconfigloader_test.go

@@ -15,17 +15,16 @@
 package kubeconfig
 
 import (
-	"github.com/ahmetb/kubectx/internal/cmdutil"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
 
-	"github.com/ahmetb/kubectx/internal/testutil"
+	"github.com/ahmetb/kubectx/internal/cmdutil"
 )
 
 func Test_kubeconfigPath(t *testing.T) {
-	defer testutil.WithEnvVar("HOME", "/x/y/z")()
+	t.Setenv("HOME", "/x/y/z")
 
 	expected := filepath.FromSlash("/x/y/z/.kube/config")
 	got, err := kubeconfigPath()
@@ -38,9 +37,9 @@ func Test_kubeconfigPath(t *testing.T) {
 }
 
 func Test_kubeconfigPath_noEnvVars(t *testing.T) {
-	defer testutil.WithEnvVar("XDG_CACHE_HOME", "")()
-	defer testutil.WithEnvVar("HOME", "")()
-	defer testutil.WithEnvVar("USERPROFILE", "")()
+	t.Setenv("XDG_CACHE_HOME", "")
+	t.Setenv("HOME", "")
+	t.Setenv("USERPROFILE", "")
 
 	_, err := kubeconfigPath()
 	if err == nil {
@@ -49,7 +48,7 @@ func Test_kubeconfigPath_noEnvVars(t *testing.T) {
 }
 
 func Test_kubeconfigPath_envOvveride(t *testing.T) {
-	defer testutil.WithEnvVar("KUBECONFIG", "foo")()
+	t.Setenv("KUBECONFIG", "foo")
 
 	v, err := kubeconfigPath()
 	if err != nil {
@@ -62,7 +61,7 @@ func Test_kubeconfigPath_envOvveride(t *testing.T) {
 
 func Test_kubeconfigPath_envOvverideDoesNotSupportPathSeparator(t *testing.T) {
 	path := strings.Join([]string{"file1", "file2"}, string(os.PathListSeparator))
-	defer testutil.WithEnvVar("KUBECONFIG", path)()
+	t.Setenv("KUBECONFIG", path)
 
 	_, err := kubeconfigPath()
 	if err == nil {
@@ -71,7 +70,7 @@ func Test_kubeconfigPath_envOvverideDoesNotSupportPathSeparator(t *testing.T) {
 }
 
 func TestStandardKubeconfigLoader_returnsNotFoundErr(t *testing.T) {
-	defer testutil.WithEnvVar("KUBECONFIG", "foo")()
+	t.Setenv("KUBECONFIG", "foo")
 	kc := new(Kubeconfig).WithLoader(DefaultLoader)
 	err := kc.Parse()
 	if err == nil {

internal/printer/color_test.go

@@ -18,8 +18,6 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
-
-	"github.com/ahmetb/kubectx/internal/testutil"
 )
 
 var (
@@ -27,8 +25,8 @@ var (
 )
 
 func Test_useColors_forceColors(t *testing.T) {
-	defer testutil.WithEnvVar("_KUBECTX_FORCE_COLOR", "1")()
-	defer testutil.WithEnvVar("NO_COLOR", "1")()
+	t.Setenv("_KUBECTX_FORCE_COLOR", "1")
+	t.Setenv("NO_COLOR", "1")
 
 	if v := useColors(); !cmp.Equal(v, &tr) {
 		t.Fatalf("expected useColors() = true; got = %v", v)
@@ -36,7 +34,7 @@ func Test_useColors_forceColors(t *testing.T) {
 }
 
 func Test_useColors_disableColors(t *testing.T) {
-	defer testutil.WithEnvVar("NO_COLOR", "1")()
+	t.Setenv("NO_COLOR", "1")
 
 	if v := useColors(); !cmp.Equal(v, &fa) {
 		t.Fatalf("expected useColors() = false; got = %v", v)
@@ -44,8 +42,8 @@ func Test_useColors_disableColors(t *testing.T) {
 }
 
 func Test_useColors_default(t *testing.T) {
-	defer testutil.WithEnvVar("NO_COLOR", "")()
-	defer testutil.WithEnvVar("_KUBECTX_FORCE_COLOR", "")()
+	t.Setenv("NO_COLOR", "")
+	t.Setenv("_KUBECTX_FORCE_COLOR", "")
 
 	if v := useColors(); v != nil {
 		t.Fatalf("expected useColors() = nil; got=%v", *v)

internal/testutil/testutil.go

@@ -1,31 +0,0 @@
-// Copyright 2021 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package testutil
-
-import "os"
-
-// WithEnvVar sets an env var temporarily. Call its return value
-// in defer to restore original value in env (if exists).
-func WithEnvVar(key, value string) func() {
-	orig, ok := os.LookupEnv(key)
-	os.Setenv(key, value)
-	return func() {
-		if ok {
-			os.Setenv(key, orig)
-		} else {
-			os.Unsetenv(key)
-		}
-	}
-}