Merge pull request #134271 from Jefftree/scheme-nil

Add nil scheme check in GetReference

staging/src/k8s.io/client-go/tools/reference/ref.go

@@ -20,7 +20,7 @@ import (
 	"errors"
 	"fmt"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -63,6 +63,9 @@ func GetReference(scheme *runtime.Scheme, obj runtime.Object) (*v1.ObjectReferen
 	//
 	// TODO: This doesn't work for CRDs, which are not registered in scheme.
 	if gvk.Empty() {
+		if scheme == nil {
+			return nil, errors.New("scheme is required to look up gvk")
+		}
 		gvks, _, err := scheme.ObjectKinds(obj)
 		if err != nil {
 			return nil, err

staging/src/k8s.io/client-go/tools/reference/ref_test.go

@@ -72,3 +72,41 @@ func TestGetReferenceRefVersion(t *testing.T) {
 		})
 	}
 }
+
+func TestGetReferenceNilScheme(t *testing.T) {
+	input := &TestRuntimeObj{
+		ObjectMeta: metav1.ObjectMeta{},
+	}
+	_, err := GetReference(nil, input)
+	if err == nil {
+		t.Fatal("expected an error")
+	}
+	if err.Error() != "scheme is required to look up gvk" {
+		t.Errorf("expected %q, got %q", "scheme is required to look up gvk", err.Error())
+	}
+}
+
+func TestGetReferenceNilSchemeWithPopulatedGVK(t *testing.T) {
+	input := &TestRuntimeObj{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "foo.group/v3",
+			Kind:       "Bar",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "a-name",
+		},
+	}
+	ref, err := GetReference(nil, input)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if ref.APIVersion != "foo.group/v3" {
+		t.Errorf("expected %q, got %q", "foo.group/v3", ref.APIVersion)
+	}
+	if ref.Kind != "Bar" {
+		t.Errorf("expected %q, got %q", "Bar", ref.Kind)
+	}
+	if ref.Name != "a-name" {
+		t.Errorf("expected %q, got %q", "a-name", ref.Name)
+	}
+}