kubens: use context to cancel slow-query warning timer after API returns

Replace done channel + defer with context.WithCancel so the warning
goroutine is cancelled immediately when queryNamespaces returns, not
when Run returns (which could be minutes later while user browses fzf).
Also thread the context into queryNamespaces so the k8s List call
respects it.

https://claude.ai/code/session_01XJXHq8WG22iqX8KaDb9RZz

.github/workflows/bash-frozen.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
       - name: Comment on PR if author is not ahmetb
         if: github.event.pull_request.user.login != 'ahmetb'
-        uses: actions/github-script@v8
+        uses: actions/github-script@v7
         with:
           script: |
             const body = [

cmd/kubens/flags.go

@@ -38,7 +38,7 @@ func parseArgs(argv []string) Op {
 
 	if n == 0 {
 		if cmdutil.IsInteractiveMode(os.Stdout) {
-			return InteractiveSwitchOp{SelfCmd: os.Args[0]}
+			return InteractiveSwitchOp{}
 		}
 		return ListOp{}
 	}

cmd/kubens/fzf.go

@@ -16,26 +16,23 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
-	"os"
 	"os/exec"
 	"strings"
+	"time"
 
 	"github.com/ahmetb/kubectx/internal/cmdutil"
-	"github.com/ahmetb/kubectx/internal/env"
 	"github.com/ahmetb/kubectx/internal/kubeconfig"
 	"github.com/ahmetb/kubectx/internal/printer"
 )
 
-type InteractiveSwitchOp struct {
-	SelfCmd string
-}
+type InteractiveSwitchOp struct{}
 
 // TODO(ahmetb) This method is heavily repetitive vs kubectx/fzf.go.
 func (op InteractiveSwitchOp) Run(_, stderr io.Writer) error {
-	// parse kubeconfig just to see if it can be loaded
 	kc := new(kubeconfig.Kubeconfig).WithLoader(kubeconfig.DefaultLoader)
 	defer kc.Close()
 	if err := kc.Parse(); err != nil {
@@ -46,23 +43,48 @@ func (op InteractiveSwitchOp) Run(_, stderr io.Writer) error {
 		return fmt.Errorf("kubeconfig error: %w", err)
 	}
 
-	ctxNames, err := kc.ContextNames()
+	ctx, err := kc.GetCurrentContext()
 	if err != nil {
-		return fmt.Errorf("failed to get context names: %w", err)
+		return fmt.Errorf("failed to get current context: %w", err)
 	}
-	if len(ctxNames) == 0 {
-		return errors.New("no contexts found in the kubeconfig file")
+	if ctx == "" {
+		return errors.New("current-context is not set")
+	}
+	curNs, err := kc.NamespaceOfContext(ctx)
+	if err != nil {
+		return fmt.Errorf("cannot read current namespace: %w", err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	go func() {
+		select {
+		case <-time.After(3 * time.Second):
+			printer.Warning(stderr, `listing namespaces is taking long, switch to a namespace directly with "kubens -f <ns>"`)
+		case <-ctx.Done():
+		}
+	}()
+
+	ns, err := queryNamespaces(ctx, kc)
+	cancel()
+	if err != nil {
+		return fmt.Errorf("could not list namespaces (is the cluster accessible?): %w", err)
+	}
+
+	var input bytes.Buffer
+	for _, c := range ns {
+		s := c
+		if c == curNs {
+			s = printer.ActiveItemColor.Sprint(c)
+		}
+		fmt.Fprintf(&input, "%s\n", s)
 	}
 
 	cmd := exec.Command("fzf", "--ansi", "--no-preview")
-	var out bytes.Buffer
-	cmd.Stdin = os.Stdin
+	cmd.Stdin = &input
 	cmd.Stderr = stderr
+	var out bytes.Buffer
 	cmd.Stdout = &out
 
-	cmd.Env = append(os.Environ(),
-		fmt.Sprintf("FZF_DEFAULT_COMMAND=%s", op.SelfCmd),
-		fmt.Sprintf("%s=1", env.EnvForceColor))
 	if err := cmd.Run(); err != nil {
 		var exitErr *exec.ExitError
 		if !errors.As(err, &exitErr) {

cmd/kubens/list.go

@@ -21,6 +21,7 @@ import (
 	"io"
 	"os"
 	"slices"
+	"time"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
@@ -52,7 +53,17 @@ func (op ListOp) Run(stdout, stderr io.Writer) error {
 		return fmt.Errorf("cannot read current namespace: %w", err)
 	}
 
-	ns, err := queryNamespaces(kc)
+	ctx, cancel := context.WithCancel(context.Background())
+	go func() {
+		select {
+		case <-time.After(3 * time.Second):
+			printer.Warning(stderr, `listing namespaces is taking long, switch to a namespace directly with "kubens -f <ns>"`)
+		case <-ctx.Done():
+		}
+	}()
+
+	ns, err := queryNamespaces(ctx, kc)
+	cancel()
 	if err != nil {
 		return fmt.Errorf("could not list namespaces (is the cluster accessible?): %w", err)
 	}
@@ -67,7 +78,7 @@ func (op ListOp) Run(stdout, stderr io.Writer) error {
 	return nil
 }
 
-func queryNamespaces(kc *kubeconfig.Kubeconfig) ([]string, error) {
+func queryNamespaces(ctx context.Context, kc *kubeconfig.Kubeconfig) ([]string, error) {
 	if os.Getenv("_MOCK_NAMESPACES") != "" {
 		return []string{"ns1", "ns2"}, nil
 	}
@@ -81,7 +92,7 @@ func queryNamespaces(kc *kubeconfig.Kubeconfig) ([]string, error) {
 	var next string
 	for {
 		list, err := clientset.CoreV1().Namespaces().List(
-			context.Background(),
+			ctx,
 			metav1.ListOptions{
 				Limit:    500,
 				Continue: next,