fix: Address 4 PR reviewer comments on kustomize fallback implementation

Agent-Logs-Url: https://github.com/helmfile/chartify/sessions/6499602a-94b2-481c-ac49-a2fc2d015090

Co-authored-by: yxxhero <11087727+yxxhero@users.noreply.github.com>

Author: Copilot

kubectl_kustomize_test.go

@@ -2,7 +2,6 @@ package chartify
 
 import (
 	"os"
-	"os/exec"
 	"path/filepath"
 	"testing"
 
@@ -14,9 +13,32 @@ import (
 // in TestKustomizeBin.
 func TestKubectlKustomize(t *testing.T) {
 	t.Run("KustomizeBuild succeeds with kubectl kustomize option", func(t *testing.T) {
-		if _, err := exec.LookPath("kubectl"); err != nil {
-			t.Skip("kubectl binary not found in PATH")
-		}
+		// Create a stub kubectl that handles the kustomize subcommand,
+		// so this test is self-contained and not skipped when kubectl is absent.
+		stubDir := t.TempDir()
+		stubKubectl := filepath.Join(stubDir, "kubectl")
+		// The stub writes minimal valid YAML to the -o output file.
+		stubScript := []byte(`#!/bin/sh
+# Stub kubectl for testing kubectl kustomize
+if [ "$1" = "kustomize" ]; then
+  shift
+  OUTPUT=""
+  while [ $# -gt 0 ]; do
+    case "$1" in
+      -o) OUTPUT="$2"; shift 2;;
+      *) shift;;
+    esac
+  done
+  if [ -n "$OUTPUT" ]; then
+    printf 'apiVersion: v1\nkind: List\nitems: []\n' > "$OUTPUT"
+  fi
+fi
+`)
+		require.NoError(t, os.WriteFile(stubKubectl, stubScript, 0755))
+
+		origPath := os.Getenv("PATH")
+		defer os.Setenv("PATH", origPath)
+		os.Setenv("PATH", stubDir+":"+origPath)
 
 		tmpDir := t.TempDir()
 		srcDir := t.TempDir()

patch.go

@@ -187,6 +187,9 @@ resources:
 
 	if !r.isUsingKubectlKustomize() {
 		kustomizeArgs = append([]string{"build", tempDir}, kustomizeArgs...)
+	} else {
+		// kubectl kustomize does not use the "build" subcommand; pass tempDir as the target directly.
+		kustomizeArgs = append([]string{tempDir}, kustomizeArgs...)
 	}
 
 	if u.EnableAlphaPlugins {

runner.go

@@ -163,10 +163,10 @@ func (r *Runner) runBytes(envs map[string]string, dir, cmd string, args ...strin
 		wrappedErr := fmt.Errorf(`%w
 
 COMMAND:
- %s
+%s
 
 OUTPUT:
- %s`,
+%s`,
 			err,
 			indent(c, "  "),
 			indent(string(errBytes), "  "),

util_test.go

@@ -122,11 +122,15 @@ func TestKustomizeBin(t *testing.T) {
 	})
 
 	t.Run("KUSTOMIZE_BIN environment variable", func(t *testing.T) {
-		if _, ok := os.LookupEnv("KUSTOMIZE_BIN"); ok {
-			t.Skip("KUSTOMIZE_BIN environment variable is already set")
-		}
+		origVal, hadVal := os.LookupEnv("KUSTOMIZE_BIN")
+		defer func() {
+			if hadVal {
+				os.Setenv("KUSTOMIZE_BIN", origVal)
+			} else {
+				os.Unsetenv("KUSTOMIZE_BIN")
+			}
+		}()
 		os.Setenv("KUSTOMIZE_BIN", "/custom/kustomize")
-		defer os.Unsetenv("KUSTOMIZE_BIN")
 		r := New()
 		got := r.kustomizeBin()
 		want := "/custom/kustomize"
@@ -148,6 +152,15 @@ func TestKustomizeBin(t *testing.T) {
 		defer os.Setenv("PATH", origPath)
 		os.Setenv("PATH", binDir)
 
+		// Ensure KUSTOMIZE_BIN does not override PATH-based lookup.
+		origKustomizeBin, hadKustomizeBin := os.LookupEnv("KUSTOMIZE_BIN")
+		defer func() {
+			if hadKustomizeBin {
+				os.Setenv("KUSTOMIZE_BIN", origKustomizeBin)
+			}
+		}()
+		os.Unsetenv("KUSTOMIZE_BIN")
+
 		r := New()
 		got := r.kustomizeBin()
 		want := "kubectl kustomize"
@@ -173,6 +186,15 @@ func TestKustomizeBin(t *testing.T) {
 		defer os.Setenv("PATH", origPath)
 		os.Setenv("PATH", binDir)
 
+		// Ensure KUSTOMIZE_BIN does not override PATH-based lookup.
+		origKustomizeBin, hadKustomizeBin := os.LookupEnv("KUSTOMIZE_BIN")
+		defer func() {
+			if hadKustomizeBin {
+				os.Setenv("KUSTOMIZE_BIN", origKustomizeBin)
+			}
+		}()
+		os.Unsetenv("KUSTOMIZE_BIN")
+
 		r := New()
 		got := r.kustomizeBin()
 		want := "kustomize"
@@ -190,6 +212,15 @@ func TestKustomizeBin(t *testing.T) {
 		defer os.Setenv("PATH", origPath)
 		os.Setenv("PATH", binDir)
 
+		// Ensure KUSTOMIZE_BIN does not override PATH-based lookup.
+		origKustomizeBin, hadKustomizeBin := os.LookupEnv("KUSTOMIZE_BIN")
+		defer func() {
+			if hadKustomizeBin {
+				os.Setenv("KUSTOMIZE_BIN", origKustomizeBin)
+			}
+		}()
+		os.Unsetenv("KUSTOMIZE_BIN")
+
 		r := New()
 		got := r.kustomizeBin()
 		want := "kustomize"