apiextensions: allow Description in the root schema for subresources

staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/validation/validation.go

@@ -291,7 +291,7 @@ func ValidateCustomResourceDefinitionValidation(customResourceValidation *apiext
 	}
 
 	if schema := customResourceValidation.OpenAPIV3Schema; schema != nil {
-		// if subresources are enabled, only "properties" and "required" is allowed inside the root schema
+		// if subresources are enabled, only "properties", "required" and "description" are allowed inside the root schema
 		if utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceSubresources) && statusSubresourceEnabled {
 			v := reflect.ValueOf(schema).Elem()
 			for i := 0; i < v.NumField(); i++ {
@@ -300,8 +300,8 @@ func ValidateCustomResourceDefinitionValidation(customResourceValidation *apiext
 					continue
 				}
 
-				if name := v.Type().Field(i).Name; name != "Properties" && name != "Required" {
-					allErrs = append(allErrs, field.Invalid(fldPath.Child("openAPIV3Schema"), *schema, fmt.Sprintf(`must only have "properties" or "required" at the root if the status subresource is enabled`)))
+				if name := v.Type().Field(i).Name; name != "Properties" && name != "Required" && name != "Description" {
+					allErrs = append(allErrs, field.Invalid(fldPath.Child("openAPIV3Schema"), *schema, fmt.Sprintf(`must only have "properties", "required" or "description" at the root if the status subresource is enabled`)))
 					break
 				}
 			}

staging/src/k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/validation/validation_test.go

@@ -849,14 +849,15 @@ func TestValidateCustomResourceDefinitionValidation(t *testing.T) {
 			wantError:     true,
 		},
 		{
-			name: "properties and required with status",
+			name: "properties, required and description with status",
 			input: apiextensions.CustomResourceValidation{
 				OpenAPIV3Schema: &apiextensions.JSONSchemaProps{
 					Properties: map[string]apiextensions.JSONSchemaProps{
 						"spec":   {},
 						"status": {},
 					},
-					Required: []string{"spec", "status"},
+					Required:    []string{"spec", "status"},
+					Description: "This is a description",
 				},
 			},
 			statusEnabled: true,

staging/src/k8s.io/apiextensions-apiserver/test/integration/subresources_test.go

@@ -359,7 +359,8 @@ func TestValidationSchema(t *testing.T) {
 				},
 			},
 		},
-		Required: []string{"spec"},
+		Required:    []string{"spec"},
+		Description: "This is a description at the root of the schema",
 	}
 	noxuDefinition, err = testserver.CreateNewCustomResourceDefinition(noxuDefinition, apiExtensionClient, dynamicClient)
 	if err != nil {