Make APIGroup optional and modify validation

pkg/apis/core/types.go

@@ -3976,8 +3976,11 @@ type LocalObjectReference struct {
 
 // TypedLocalObjectReference contains enough information to let you locate the typed referenced object inside the same namespace.
 type TypedLocalObjectReference struct {
-	// APIGroup is the group for the resource being referenced
-	APIGroup string
+	// APIGroup is the group for the resource being referenced.
+	// If APIGroup is not specified, the specified Kind must be in the core API group.
+	// For any other third-party types, APIGroup is required.
+	// +optional
+	APIGroup *string
 	// Kind is the type of resource being referenced
 	Kind string
 	// Name is the name of resource being referenced

pkg/apis/core/validation/validation.go

@@ -36,6 +36,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	unversionedvalidation "k8s.io/apimachinery/pkg/apis/meta/v1/validation"
 	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/util/diff"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"k8s.io/apimachinery/pkg/util/sets"
@@ -1501,8 +1502,9 @@ var supportedReclaimPolicy = sets.NewString(string(core.PersistentVolumeReclaimD
 
 var supportedVolumeModes = sets.NewString(string(core.PersistentVolumeBlock), string(core.PersistentVolumeFilesystem))
 
-var supportedDataSourceKinds = sets.NewString(string("VolumeSnapshot"))
-var supportedDataSourceAPIGroups = sets.NewString(string("snapshot.storage.k8s.io"))
+var supportedDataSourceAPIGroupKinds = map[schema.GroupKind]bool{
+	{Group: "snapshot.storage.k8s.io", Kind: "VolumeSnapshot"}: true,
+}
 
 func ValidatePersistentVolume(pv *core.PersistentVolume) field.ErrorList {
 	metaPath := field.NewPath("metadata")
@@ -1833,10 +1835,18 @@ func ValidatePersistentVolumeClaimSpec(spec *core.PersistentVolumeClaimSpec, fld
 	} else if spec.DataSource != nil {
 		if len(spec.DataSource.Name) == 0 {
 			allErrs = append(allErrs, field.Required(fldPath.Child("dataSource", "name"), ""))
-		} else if !supportedDataSourceKinds.Has(string(spec.DataSource.Kind)) {
-			allErrs = append(allErrs, field.NotSupported(fldPath.Child("dataSource"), spec.DataSource.Kind, supportedDataSourceKinds.List()))
-		} else if !supportedDataSourceAPIGroups.Has(string(spec.DataSource.APIGroup)) {
-			allErrs = append(allErrs, field.NotSupported(fldPath.Child("dataSource"), spec.DataSource.APIGroup, supportedDataSourceAPIGroups.List()))
+		}
+
+		groupKind := schema.GroupKind{Group: "", Kind: spec.DataSource.Kind}
+		if spec.DataSource.APIGroup != nil {
+			groupKind.Group = string(*spec.DataSource.APIGroup)
+		}
+		groupKindList := make([]string, 0, len(supportedDataSourceAPIGroupKinds))
+		for grp := range supportedDataSourceAPIGroupKinds {
+			groupKindList = append(groupKindList, grp.String())
+		}
+		if !supportedDataSourceAPIGroupKinds[groupKind] {
+			allErrs = append(allErrs, field.NotSupported(fldPath.Child("dataSource"), groupKind.String(), groupKindList))
 		}
 	}
 

pkg/apis/core/validation/validation_test.go

@@ -726,7 +726,7 @@ func testVolumeSnapshotDataSourceInSpec(name string, kind string, apiGroup strin
 		},
 		StorageClassName: &scName,
 		DataSource: &core.TypedLocalObjectReference{
-			APIGroup: apiGroup,
+			APIGroup: &apiGroup,
 			Kind:     kind,
 			Name:     name,
 		},

staging/src/k8s.io/api/core/v1/types.go

@@ -4495,8 +4495,11 @@ type LocalObjectReference struct {
 // TypedLocalObjectReference contains enough information to let you locate the
 // typed referenced object inside the same namespace.
 type TypedLocalObjectReference struct {
-	// APIGroup is the group for the resource being referenced
-	APIGroup string `json:"apiGroup" protobuf:"bytes,1,opt,name=apiGroup"`
+	// APIGroup is the group for the resource being referenced.
+	// If APIGroup is not specified, the specified Kind must be in the core API group.
+	// For any other third-party types, APIGroup is required.
+	// +optional
+	APIGroup *string `json:"apiGroup" protobuf:"bytes,1,opt,name=apiGroup"`
 	// Kind is the type of resource being referenced
 	Kind string `json:"kind" protobuf:"bytes,2,opt,name=kind"`
 	// Name is the name of resource being referenced