move check for noop managed field timestamp updates

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

@@ -654,9 +654,6 @@ func (p *patcher) patchResource(ctx context.Context, scope *RequestScope) (runti
 	}
 
 	transformers := []rest.TransformFunc{p.applyPatch, p.applyAdmission, dedupOwnerReferencesTransformer}
-	if scope.FieldManager != nil {
-		transformers = append(transformers, fieldmanager.IgnoreManagedFieldsTimestampsTransformer)
-	}
 
 	wasCreated := false
 	p.updatedObjectInfo = rest.DefaultUpdatedObjectInfo(nil, transformers...)

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

@@ -189,15 +189,6 @@ func UpdateResource(r rest.Updater, scope *RequestScope, admit admission.Interfa
 			})
 		}
 
-		// Ignore changes that only affect managed fields
-		// timestamps. FieldManager can't know about changes
-		// like normalized fields, defaulted fields and other
-		// mutations.
-		// Only makes sense when SSA field manager is being used
-		if scope.FieldManager != nil {
-			transformers = append(transformers, fieldmanager.IgnoreManagedFieldsTimestampsTransformer)
-		}
-
 		createAuthorizerAttributes := authorizer.AttributesRecord{
 			User:            userInfo,
 			ResourceRequest: true,

staging/src/k8s.io/apiserver/pkg/registry/generic/registry/store.go

@@ -38,6 +38,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager"
 	genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
 	"k8s.io/apiserver/pkg/registry/generic"
 	"k8s.io/apiserver/pkg/registry/rest"
@@ -671,6 +672,15 @@ func (e *Store) Update(ctx context.Context, name string, objInfo rest.UpdatedObj
 		if err := rest.BeforeUpdate(e.UpdateStrategy, ctx, obj, existing); err != nil {
 			return nil, nil, err
 		}
+
+		// Ignore changes that only affect managed fields timestamps.
+		// FieldManager can't know about changes like normalized fields, defaulted
+		// fields and other mutations.
+		obj, err = fieldmanager.IgnoreManagedFieldsTimestampsTransformer(ctx, obj, existing)
+		if err != nil {
+			return nil, nil, err
+		}
+
 		// at this point we have a fully formed object.  It is time to call the validators that the apiserver
 		// handling chain wants to enforce.
 		if updateValidation != nil {

test/integration/apiserver/apply/apply_test.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/require"
 	"sigs.k8s.io/yaml"
 
 	appsv1 "k8s.io/api/apps/v1"
@@ -249,6 +250,55 @@ func getRV(obj runtime.Object) (string, error) {
 	return acc.GetResourceVersion(), nil
 }
 
+func TestNoopChangeCreationTime(t *testing.T) {
+	client, closeFn := setup(t)
+	defer closeFn()
+
+	ssBytes := []byte(`{
+		"apiVersion": "v1",
+		"kind": "ConfigMap",
+		"metadata": {
+			"name": "myconfig",
+			"creationTimestamp": null,
+			"resourceVersion": null
+		},
+		"data": {
+			"key": "value"
+		}
+	}`)
+
+	obj, err := client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
+		Namespace("default").
+		Param("fieldManager", "apply_test").
+		Resource("configmaps").
+		Name("myconfig").
+		Body(ssBytes).
+		Do(context.TODO()).
+		Get()
+	if err != nil {
+		t.Fatalf("Failed to create object: %v", err)
+	}
+
+	require.NoError(t, err)
+	// Sleep for one second to make sure that the times of each update operation is different.
+	time.Sleep(1200 * time.Millisecond)
+
+	newObj, err := client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
+		Namespace("default").
+		Param("fieldManager", "apply_test").
+		Resource("configmaps").
+		Name("myconfig").
+		Body(ssBytes).
+		Do(context.TODO()).
+		Get()
+	if err != nil {
+		t.Fatalf("Failed to create object: %v", err)
+	}
+
+	require.NoError(t, err)
+	require.Equal(t, obj, newObj)
+}
+
 // TestNoSemanticUpdateAppleSameResourceVersion makes sure that APPLY requests which makes no semantic changes
 // will not change the resource version (no write to etcd is done)
 //