Unversioned types should decode no matter what the requested version is

pkg/runtime/scheme.go

@@ -519,6 +519,15 @@ func (s *Scheme) convertToVersion(copy bool, in Object, target GroupVersioner) (
 
 	gvk, ok := target.KindForGroupVersionKinds(kinds)
 	if !ok {
+		// try to see if this type is listed as unversioned (for legacy support)
+		// TODO: when we move to server API versions, we should completely remove the unversioned concept
+		if unversionedKind, ok := s.unversionedTypes[t]; ok {
+			if gvk, ok := target.KindForGroupVersionKinds([]unversioned.GroupVersionKind{unversionedKind}); ok {
+				return copyAndSetTargetKind(copy, s, in, gvk)
+			}
+			return copyAndSetTargetKind(copy, s, in, unversionedKind)
+		}
+
 		// TODO: should this be a typed error?
 		return nil, fmt.Errorf("%v is not suitable for converting to %q", t, target)
 	}

pkg/runtime/scheme_test.go

@@ -625,6 +625,17 @@ func TestConvertToVersion(t *testing.T) {
 				A: "test",
 			},
 		},
+		// unversioned type returned when not included in the target types
+		{
+			scheme: GetTestScheme(),
+			in:     &UnversionedType{A: "test"},
+			gv:     unversioned.GroupVersions{{Group: "other", Version: "v2"}},
+			same:   true,
+			out: &UnversionedType{
+				MyWeirdCustomEmbeddedVersionKindField: MyWeirdCustomEmbeddedVersionKindField{APIVersion: "v1", ObjectKind: "UnversionedType"},
+				A: "test",
+			},
+		},
 		// detected as already being in the target version
 		{
 			scheme: GetTestScheme(),