fix(pkg/lint): unmarshals Chart.yaml strictly

When "helm lint" is run, it now errors on invalid chartfiles,
e.g. those with duplicate keys

Closes #12381

Signed-off-by: Edward Miller <edmiller287@gmail.com>

pkg/chart/v2/util/chartfile.go

@@ -33,7 +33,7 @@ func LoadChartfile(filename string) (*chart.Metadata, error) {
 		return nil, err
 	}
 	y := new(chart.Metadata)
-	err = yaml.Unmarshal(b, y)
+	err = yaml.UnmarshalStrict(b, y)
 	return y, err
 }
 

pkg/lint/lint_test.go

@@ -35,6 +35,7 @@ const badYamlFileDir = "rules/testdata/albatross"
 const goodChartDir = "rules/testdata/goodone"
 const subChartValuesDir = "rules/testdata/withsubchart"
 const malformedTemplate = "rules/testdata/malformed-template"
+const invalidChartFileDir = "rules/testdata/invalidchartfile"
 
 func TestBadChart(t *testing.T) {
 	m := RunAll(badChartDir, values, namespace).Messages
@@ -90,6 +91,16 @@ func TestInvalidYaml(t *testing.T) {
 	}
 }
 
+func TestInvalidChartYaml(t *testing.T) {
+	m := All(invalidChartFileDir, values, namespace, strict).Messages
+	if len(m) != 1 {
+		t.Fatalf("All didn't fail with expected errors, got %#v", m)
+	}
+	if !strings.Contains(m[0].Err.Error(), "unable to parse YAML") {
+		t.Errorf("All didn't have the error for duplicate YAML keys")
+	}
+}
+
 func TestBadValues(t *testing.T) {
 	m := RunAll(badValuesFileDir, values, namespace).Messages
 	if len(m) < 1 {

pkg/lint/rules/testdata/invalidchartfile/Chart.yaml

@@ -0,0 +1,5 @@
+name: some-chart
+apiVersion: v2
+apiVersion: v1
+description: A Helm chart for Kubernetes
+version: 1.3.0