fix panic when calling ToUnstructured on nil metav1.Time

Author: com6056

value/reflectcache.go

@@ -184,18 +184,18 @@ func (e TypeReflectCacheEntry) ToUnstructured(sv reflect.Value) (interface{}, er
 	// This is based on https://github.com/kubernetes/kubernetes/blob/82c9e5c814eb7acc6cc0a090c057294d0667ad66/staging/src/k8s.io/apimachinery/pkg/runtime/converter.go#L505
 	// and is intended to replace it.
 
+	// Check if the object is a nil pointer.
+	if sv.Kind() == reflect.Ptr && sv.IsNil() {
+		// We're done - we don't need to store anything.
+		return nil, nil
+	}
 	// Check if the object has a custom string converter and use it if available, since it is much more efficient
 	// than round tripping through json.
 	if converter, ok := e.getUnstructuredConverter(sv); ok {
 		return converter.ToUnstructured(), nil
 	}
 	// Check if the object has a custom JSON marshaller/unmarshaller.
 	if marshaler, ok := e.getJsonMarshaler(sv); ok {
-		if sv.Kind() == reflect.Ptr && sv.IsNil() {
-			// We're done - we don't need to store anything.
-			return nil, nil
-		}
-
 		data, err := marshaler.MarshalJSON()
 		if err != nil {
 			return nil, err

value/reflectcache_test.go

@@ -19,6 +19,7 @@ package value
 import (
 	"reflect"
 	"testing"
+	"time"
 )
 
 type CustomValue struct {
@@ -39,6 +40,21 @@ func (c *CustomPointer) MarshalJSON() ([]byte, error) {
 	return c.data, nil
 }
 
+// Mimics https://github.com/kubernetes/apimachinery/blob/master/pkg/apis/meta/v1/time.go.
+type Time struct {
+	time.Time
+}
+
+// ToUnstructured implements the value.UnstructuredConverter interface.
+func (t Time) ToUnstructured() interface{} {
+	if t.IsZero() {
+		return nil
+	}
+	buf := make([]byte, 0, len(time.RFC3339))
+	buf = t.UTC().AppendFormat(buf, time.RFC3339)
+	return string(buf)
+}
+
 func TestToUnstructured(t *testing.T) {
 	testcases := []struct {
 		Data     string
@@ -63,6 +79,7 @@ func TestToUnstructured(t *testing.T) {
 				CustomValue{data: []byte(tc.Data)},
 				&CustomValue{data: []byte(tc.Data)},
 				&CustomPointer{data: []byte(tc.Data)},
+				&CustomPointer{nil},
 			}
 			for _, custom := range custom {
 				rv := reflect.ValueOf(custom)
@@ -78,6 +95,39 @@ func TestToUnstructured(t *testing.T) {
 	}
 }
 
+func timePtr(t time.Time) *time.Time { return &t }
+
+func TestTimeToUnstructured(t *testing.T) {
+	testcases := []struct {
+		Name     string
+		Time     *time.Time
+		Expected interface{}
+	}{
+		{Name: "nil", Time: nil, Expected: nil},
+		{Name: "zero", Time: &time.Time{}, Expected: nil},
+		{Name: "1", Time: timePtr(time.Time{}.Add(time.Second)), Expected: "0001-01-01T00:00:01Z"},
+	}
+
+	for _, tc := range testcases {
+		tc := tc
+		t.Run(tc.Name, func(t *testing.T) {
+			t.Parallel()
+			var time *Time
+			rv := reflect.ValueOf(time)
+			if tc.Time != nil {
+				rv = reflect.ValueOf(Time{Time: *tc.Time})
+			}
+			result, err := TypeReflectEntryOf(rv.Type()).ToUnstructured(rv)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !reflect.DeepEqual(result, tc.Expected) {
+				t.Errorf("expected %#v but got %#v", tc.Expected, result)
+			}
+		})
+	}
+}
+
 func TestTypeReflectEntryOf(t *testing.T) {
 	testString := ""
 	tests := map[string]struct {