fix(lint): resolve unused variable and deprecated ValidateMetadataName warnings

Signed-off-by: Dasmat13 <gptdasmat@gmail.com>

pkg/chart/v2/lint/rules/chartfile.go

@@ -21,9 +21,11 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/Masterminds/semver/v3"
 	"github.com/asaskevich/govalidator"
+	"k8s.io/apimachinery/pkg/api/validation"
 	"sigs.k8s.io/yaml"
 
 	chart "helm.sh/helm/v4/pkg/chart/v2"
@@ -124,8 +126,8 @@ func validateChartName(cf *chart.Metadata) error {
 	// Chart names must also be valid Kubernetes metadata names so they can be
 	// used safely as resource name prefixes (lowercase, alphanumeric, hyphens
 	// and dots only; must start and end with an alphanumeric character).
-	if err := chartutil.ValidateMetadataName(cf.Name); err != nil {
+	if errs := validation.NameIsDNSSubdomain(cf.Name, false); len(errs) > 0 {
-		return fmt.Errorf("chart name %q is not a valid Kubernetes name: use lowercase letters, digits, hyphens, and dots only (e.g. my-chart, my.chart)", cf.Name)
+		return fmt.Errorf("chart name %q is not a valid Kubernetes name: %s", cf.Name, strings.Join(errs, ", "))
 	}
 	return nil
 }

pkg/chart/v2/lint/rules/chartfile_test.go

@@ -61,6 +61,8 @@ func TestValidateChartName(t *testing.T) {
 	// empty name (badChart has name: "")
 	require.Error(t, validateChartName(badChart), "validateChartName to return a linter error, got no error")
 
+	assert.Error(t, validateChartName(badChartName), "expected validateChartName to return a linter error for an invalid name, got no error")
+
 	invalidNames := []struct {
 		name   string
 		reason string

pkg/chart/v2/lint/rules/testdata/badchartname/Chart.yaml

@@ -1,5 +1,5 @@
 apiVersion: v2
 description: A Helm chart for Kubernetes
 version: 0.1.0
-name: "MyInvalidChart"
+name: "../badchartname"
 type: application