refactor(version): avoid linking Kubernetes clientset for build info

Signed-off-by: Yugo Kobayashi <kobdotsh@gmail.com>

internal/version/clientgo.go

@@ -21,7 +21,7 @@ import (
 	"runtime/debug"
 	"slices"
 
-	_ "k8s.io/client-go/kubernetes" // Force k8s.io/client-go to be included in the build
+	_ "k8s.io/client-go/pkg/version" // Force the k8s.io/client-go module version into build info
 )
 
 func K8sIOClientGoModVersion() (string, error) {

internal/version/clientgo_test.go

@@ -17,6 +17,10 @@ limitations under the License.
 package version
 
 import (
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -28,3 +32,36 @@ func TestK8sClientGoModVersion(t *testing.T) {
 	_, err := K8sIOClientGoModVersion()
 	require.ErrorContains(t, err, "k8s.io/client-go not found in build info")
 }
+
+func TestK8sClientGoModVersionFromBuiltBinary(t *testing.T) {
+	cmd := exec.CommandContext(t.Context(), "go", "list", "-m", "-f={{.Version}}", "k8s.io/client-go")
+	expectedVersion, err := cmd.CombinedOutput()
+	require.NoError(t, err, string(expectedVersion))
+
+	binary := filepath.Join(t.TempDir(), "clientgo-version")
+	if runtime.GOOS == "windows" {
+		binary += ".exe"
+	}
+
+	cmd = exec.CommandContext(t.Context(), "go", "build", "-o", binary, "./testdata/clientgo-version")
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err, string(output))
+
+	cmd = exec.CommandContext(t.Context(), binary)
+	output, err = cmd.CombinedOutput()
+	require.NoError(t, err, string(output))
+	require.Equal(t, strings.TrimSpace(string(expectedVersion)), strings.TrimSpace(string(output)))
+}
+
+func TestK8sClientGoDependencyIsLightweight(t *testing.T) {
+	cmd := exec.CommandContext(t.Context(), "go", "list", "-deps", ".")
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err, string(output))
+
+	dependencies := strings.Fields(string(output))
+	require.Contains(t, dependencies, "k8s.io/client-go/pkg/version")
+	for _, dependency := range dependencies {
+		require.NotEqual(t, "k8s.io/client-go/kubernetes", dependency)
+		require.NotContains(t, dependency, "k8s.io/client-go/kubernetes/")
+	}
+}

internal/version/testdata/clientgo-version/main.go

@@ -0,0 +1,34 @@
+/*
+Copyright The Helm 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 main
+
+import (
+	"fmt"
+	"os"
+
+	"helm.sh/helm/v4/internal/version"
+)
+
+func main() {
+	clientGoVersion, err := version.K8sIOClientGoModVersion()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	fmt.Print(clientGoVersion)
+}