Allow specifying the hub group-version for a handler

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_handler.go

@@ -525,6 +525,9 @@ func (r *crdHandler) getOrCreateServingInfoFor(crd *apiextensions.CustomResource
 			Resource: schema.GroupVersionResource{Group: crd.Spec.Group, Version: v.Name, Resource: crd.Status.AcceptedNames.Plural},
 			Kind:     kind,
 
+			// a handler for a specific group-version of a custom resource uses that version as the in-memory representation
+			HubGroupVersion: kind.GroupVersion(),
+
 			MetaGroupVersion: metav1.SchemeGroupVersion,
 
 			TableConvertor: storages[v.Name].CustomResource,

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/create.go

@@ -77,7 +77,7 @@ func createHandler(r rest.NamedCreater, scope RequestScope, admit admission.Inte
 			scope.err(err, w, req)
 			return
 		}
-		decoder := scope.Serializer.DecoderToVersion(s.Serializer, schema.GroupVersion{Group: gv.Group, Version: runtime.APIVersionInternal})
+		decoder := scope.Serializer.DecoderToVersion(s.Serializer, scope.HubGroupVersion)
 
 		body, err := readBody(req)
 		if err != nil {

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/patch.go

@@ -118,9 +118,10 @@ func PatchResource(r rest.Patcher, scope RequestScope, admit admission.Interface
 			return
 		}
 		gv := scope.Kind.GroupVersion()
+
 		codec := runtime.NewCodec(
 			scope.Serializer.EncoderForVersion(s.Serializer, gv),
-			scope.Serializer.DecoderToVersion(s.Serializer, schema.GroupVersion{Group: gv.Group, Version: runtime.APIVersionInternal}),
+			scope.Serializer.DecoderToVersion(s.Serializer, scope.HubGroupVersion),
 		)
 
 		userInfo, _ := request.UserFrom(ctx)
@@ -163,6 +164,8 @@ func PatchResource(r rest.Patcher, scope RequestScope, admit admission.Interface
 			kind:            scope.Kind,
 			resource:        scope.Resource,
 
+			hubGroupVersion: scope.HubGroupVersion,
+
 			createValidation: rest.AdmissionToValidateObjectFunc(admit, staticAdmissionAttributes),
 			updateValidation: rest.AdmissionToValidateObjectUpdateFunc(admit, staticAdmissionAttributes),
 			admissionCheck:   admissionCheck,
@@ -218,6 +221,8 @@ type patcher struct {
 	resource        schema.GroupVersionResource
 	kind            schema.GroupVersionKind
 
+	hubGroupVersion schema.GroupVersion
+
 	// Validation functions
 	createValidation rest.ValidateObjectFunc
 	updateValidation rest.ValidateObjectUpdateFunc
@@ -315,9 +320,8 @@ func (p *smpPatcher) applyPatchToCurrentObject(currentObject runtime.Object) (ru
 	if err := strategicPatchObject(p.defaulter, currentVersionedObject, p.patchJS, versionedObjToUpdate, p.schemaReferenceObj); err != nil {
 		return nil, err
 	}
-	// Convert the object back to unversioned (aka internal version).
-	gvk := p.kind.GroupKind().WithVersion(runtime.APIVersionInternal)
-	return p.unsafeConvertor.ConvertToVersion(versionedObjToUpdate, gvk.GroupVersion())
+	// Convert the object back to the hub version
+	return p.unsafeConvertor.ConvertToVersion(versionedObjToUpdate, p.hubGroupVersion)
 }
 
 // strategicPatchObject applies a strategic merge patch of <patchJS> to

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/rest.go

@@ -65,6 +65,9 @@ type RequestScope struct {
 	Subresource string
 
 	MetaGroupVersion schema.GroupVersion
+
+	// HubGroupVersion indicates what version objects read from etcd or incoming requests should be converted to for in-memory handling.
+	HubGroupVersion schema.GroupVersion
 }
 
 func (scope *RequestScope) err(err error, w http.ResponseWriter, req *http.Request) {

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/rest_test.go

@@ -367,6 +367,7 @@ func (tc *patchTestCase) Run(t *testing.T) {
 	kind := examplev1.SchemeGroupVersion.WithKind("Pod")
 	resource := examplev1.SchemeGroupVersion.WithResource("pods")
 	schemaReferenceObj := &examplev1.Pod{}
+	hubVersion := example.SchemeGroupVersion
 
 	for _, patchType := range []types.PatchType{types.JSONPatchType, types.MergePatchType, types.StrategicMergePatchType} {
 		// This needs to be reset on each iteration.
@@ -439,6 +440,8 @@ func (tc *patchTestCase) Run(t *testing.T) {
 			kind:            kind,
 			resource:        resource,
 
+			hubGroupVersion: hubVersion,
+
 			createValidation: rest.ValidateAllObjectFunc,
 			updateValidation: admissionValidation,
 			admissionCheck:   admissionMutation,

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/update.go

@@ -89,8 +89,9 @@ func UpdateResource(r rest.Updater, scope RequestScope, admit admission.Interfac
 		}
 		defaultGVK := scope.Kind
 		original := r.New()
+
 		trace.Step("About to convert to expected version")
-		decoder := scope.Serializer.DecoderToVersion(s.Serializer, schema.GroupVersion{Group: defaultGVK.Group, Version: runtime.APIVersionInternal})
+		decoder := scope.Serializer.DecoderToVersion(s.Serializer, scope.HubGroupVersion)
 		obj, gvk, err := decoder.Decode(body, &defaultGVK, original)
 		if err != nil {
 			err = transformDecodeError(scope.Typer, err, original, gvk, body)

staging/src/k8s.io/apiserver/pkg/endpoints/installer.go

@@ -506,6 +506,8 @@ func (a *APIInstaller) registerResourceHandlers(path string, storage rest.Storag
 		Subresource: subresource,
 		Kind:        fqKindToRegister,
 
+		HubGroupVersion: schema.GroupVersion{Group: fqKindToRegister.Group, Version: runtime.APIVersionInternal},
+
 		MetaGroupVersion: metav1.SchemeGroupVersion,
 	}
 	if a.group.MetaGroupVersion != nil {