fix: port-forward error logs failed to port forward (#9728) (#9759)

* fix: port-forward error logs `failed to port forward`

Reflect changes in `os.Process` introduced in Go 1.23

* use `reflect` to make it future proof(?)

* Add safeguards to call FieldByName

* Add basic test to getHandleFromProcess

* Fix copyright year

Co-authored-by: SeongChan Lee <[email protected]>

Author: mattsanta

pkg/skaffold/kubectl/exec_windows.go

@@ -19,7 +19,9 @@ package kubectl
 import (
 	"context"
 	"fmt"
+	"os"
 	"os/exec"
+	"reflect"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
@@ -62,11 +64,10 @@ func (c *Cmd) Start() error {
 		return fmt.Errorf("could not start the command: %w", err)
 	}
 
-	// Use `unsafe` to extract the process handle.
-	processHandle := (*struct {
-		Pid    int
-		handle windows.Handle
-	})(unsafe.Pointer(c.Process)).handle
+	processHandle, err := getHandleFromProcess(c.Process)
+	if err != nil {
+		return fmt.Errorf("could not get handle from process: %w", err)
+	}
 
 	if err := windows.AssignProcessToJobObject(handle, processHandle); err != nil {
 		return fmt.Errorf("could not assign job object: %w", err)
@@ -81,6 +82,24 @@ func (c *Cmd) Start() error {
 	return nil
 }
 
+func getHandleFromProcess(p *os.Process) (windows.Handle, error) {
+	// `os.Process` don't expose `handle uintptr` field.
+	v := reflect.ValueOf(p)
+	i := reflect.Indirect(v)
+
+	k := i.Kind()
+	if k != reflect.Struct {
+		return windows.InvalidHandle, fmt.Errorf("unexpected kind of os.Process. probably a bug: %s", k)
+	}
+
+	f := i.FieldByName("handle")
+	if f.IsZero() {
+		return windows.InvalidHandle, fmt.Errorf("could not get 'handle' field from os.Process. probably a bug")
+	}
+
+	return windows.Handle(f.Uint()), nil
+}
+
 // Run starts the specified command in a job object and waits for it to complete
 func (c *Cmd) Run() error {
 	if err := c.Start(); err != nil {

pkg/skaffold/kubectl/exec_windows_test.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2025 The Skaffold Authors
+
+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 kubectl
+
+import (
+	"context"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/sys/windows"
+)
+
+func TestGetHandleFromProcess(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skip("getHandleFromProcess only works on Windows")
+	}
+
+	ctx := context.TODO()
+	c := CommandContext(ctx, "kubectl", "--help")
+	err := c.Cmd.Start()
+	assert.Nil(t, err, "could not start command")
+
+	h, err := getHandleFromProcess(c.Process)
+	assert.NotEqual(t, h, windows.InvalidHandle, "handle is invalid")
+	assert.Nil(t, err, "could not get handle from process")
+
+	err = c.Cmd.Wait()
+	assert.Nil(t, err, "could not wait command")
+}