fix(lint): validate kubernetes resource names for chart names

Fixes #10537

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

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

@@ -121,6 +121,12 @@ func validateChartName(cf *chart.Metadata) error {
 	if name != cf.Name {
 		return fmt.Errorf("chart name %q is invalid", cf.Name)
 	}
+	// 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 {
+		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 nil
 }
 

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

@@ -67,14 +67,36 @@ func TestValidateChartYamlFormat(t *testing.T) {
 }
 
 func TestValidateChartName(t *testing.T) {
+	// empty name (badChart has name: "")
 	err := validateChartName(badChart)
 	if err == nil {
-		t.Error("validateChartName to return a linter error, got no error")
+		t.Error("validateChartName to return a linter error for empty name, got no error")
 	}
 
-	err = validateChartName(badChartName)
-	if err == nil {
-		t.Error("expected validateChartName to return a linter error for an invalid name, got no error")
+	invalidNames := []struct {
+		name   string
+		reason string
+	}{
+		{"../badchartname", "path traversal"},
+		{"MyInvalidChart", "uppercase letters"},
+		{"my_chart", "underscore"},
+		{"-my-chart", "leading hyphen"},
+		{"my-chart-", "trailing hyphen"},
+		{"my chart", "space"},
+	}
+	for _, tc := range invalidNames {
+		meta := &chart.Metadata{Name: tc.name}
+		if err := validateChartName(meta); err == nil {
+			t.Errorf("expected validateChartName to return error for %q (%s), got nil", tc.name, tc.reason)
+		}
+	}
+
+	validNames := []string{"my-chart", "my.chart", "mychart", "my-chart-v2", "1-chart", "myinvalidchart"} // "myinvalidchart" is the lowercase twin of the invalid "MyInvalidChart", confirming uppercase triggers failure
+	for _, name := range validNames {
+		meta := &chart.Metadata{Name: name}
+		if err := validateChartName(meta); err != nil {
+			t.Errorf("expected validateChartName to return no error for %q, got: %v", name, err)
+		}
 	}
 }
 

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: "../badchartname"
+name: "MyInvalidChart"
 type: application