Add --helm-debug Flag to Kustomize for Enhanced Helm Debugging (#5751)

* feat: add helm-debug flag

* revert: go.work.sum

* test: add helm chart args helm-debug test

* test: helm debug flag

* refactor: helm debug output

* style: linting

* revert: go.work.sum

plugin/builtin/helmchartinflationgenerator/HelmChartInflationGenerator.go

@@ -14,6 +14,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strings"
 
 	"sigs.k8s.io/kustomize/api/resmap"
@@ -68,6 +69,9 @@ func (p *plugin) Config(
 	if len(h.GeneralConfig().HelmConfig.ApiVersions) != 0 {
 		p.HelmChart.ApiVersions = h.GeneralConfig().HelmConfig.ApiVersions
 	}
+	if h.GeneralConfig().HelmConfig.Debug {
+		p.HelmChart.Debug = h.GeneralConfig().HelmConfig.Debug
+	}
 
 	p.h = h
 	if err = yaml.Unmarshal(config, p); err != nil {
@@ -174,13 +178,17 @@ func (p *plugin) runHelmCommand(
 		fmt.Sprintf("HELM_DATA_HOME=%s/.data", p.ConfigHome)}
 	cmd.Env = append(os.Environ(), env...)
 	err := cmd.Run()
+	errorOutput := stderr.String()
+	if slices.Contains(args, "--debug") {
+		errorOutput = " Helm stack trace:\n" + errorOutput + "\nHelm template:\n" + stdout.String() + "\n"
+	}
 	if err != nil {
 		helm := p.h.GeneralConfig().HelmConfig.Command
 		err = errors.WrapPrefixf(
 			fmt.Errorf(
 				"unable to run: '%s %s' with env=%s (is '%s' installed?): %w",
 				helm, strings.Join(args, " "), env, helm, err),
-			stderr.String(),
+			errorOutput,
 		)
 	}
 	return stdout.Bytes(), err

plugin/builtin/helmchartinflationgenerator/HelmChartInflationGenerator_test.go

@@ -959,3 +959,37 @@ chartHome: ./charts
 	assert.Contains(t, string(chartYamlContent), "name: test-chart")
 	assert.Contains(t, string(chartYamlContent), "version: 1.0.0")
 }
+
+func TestHelmChartInflationGeneratorWithDebug(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarnessWithTmpRoot(t).
+		PrepBuiltin("HelmChartInflationGenerator")
+	defer th.Reset()
+	if err := th.ErrIfNoHelm(); err != nil {
+		t.Skip("skipping: " + err.Error())
+	}
+	copyTestChartsIntoHarness(t, th)
+
+	rm := th.LoadAndRunGenerator(`
+apiVersion: builtin
+kind: HelmChartInflationGenerator
+metadata:
+  name: test-chart
+name: test-chart
+version: 1.0.0
+releaseName: test
+chartHome: ./charts
+debug: true
+`)
+
+	cm, err := rm.Resources()[0].GetFieldValue("metadata.name")
+	require.NoError(t, err)
+	assert.Equal(t, "bar", cm)
+
+	chartDir := filepath.Join(th.GetRoot(), "charts/test-chart")
+	assert.True(t, th.GetFSys().Exists(chartDir))
+
+	chartYamlContent, err := th.GetFSys().ReadFile(filepath.Join(chartDir, "Chart.yaml"))
+	require.NoError(t, err)
+	assert.Contains(t, string(chartYamlContent), "name: test-chart")
+	assert.Contains(t, string(chartYamlContent), "version: 1.0.0")
+}