apiextensions: remove ratcheting logic to allow conversion with preserveUnknownField

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

@@ -121,10 +121,10 @@ func ValidateCustomResourceDefinitionVersion(version *apiextensions.CustomResour
 // ValidateCustomResourceDefinitionSpec statically validates
 func ValidateCustomResourceDefinitionSpec(spec *apiextensions.CustomResourceDefinitionSpec, fldPath *field.Path) field.ErrorList {
 	allowDefaults := utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceDefaulting)
-	return validateCustomResourceDefinitionSpec(spec, true, allowDefaults, false, fldPath)
+	return validateCustomResourceDefinitionSpec(spec, true, allowDefaults, fldPath)
 }
 
-func validateCustomResourceDefinitionSpec(spec *apiextensions.CustomResourceDefinitionSpec, requireRecognizedVersion, allowDefaults, allowConversionWithPreserveUnknownFields bool, fldPath *field.Path) field.ErrorList {
+func validateCustomResourceDefinitionSpec(spec *apiextensions.CustomResourceDefinitionSpec, requireRecognizedVersion, allowDefaults bool, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
 
 	if len(spec.Group) == 0 {
@@ -237,7 +237,7 @@ func validateCustomResourceDefinitionSpec(spec *apiextensions.CustomResourceDefi
 		}
 	}
 
-	if !allowConversionWithPreserveUnknownFields && conversionAndPreserveUnknownFields(spec) {
+	if (spec.Conversion != nil && spec.Conversion.Strategy != apiextensions.NoneConverter) && (spec.PreserveUnknownFields == nil || *spec.PreserveUnknownFields) {
 		allErrs = append(allErrs, field.Invalid(fldPath.Child("conversion").Child("strategy"), spec.Conversion.Strategy, "must be None if spec.preserveUnknownFields is true"))
 	}
 	allErrs = append(allErrs, validateCustomResourceConversion(spec.Conversion, requireRecognizedVersion, fldPath.Child("conversion"))...)
@@ -245,10 +245,6 @@ func validateCustomResourceDefinitionSpec(spec *apiextensions.CustomResourceDefi
 	return allErrs
 }
 
-func conversionAndPreserveUnknownFields(spec *apiextensions.CustomResourceDefinitionSpec) bool {
-	return (spec.Conversion != nil && spec.Conversion.Strategy != apiextensions.NoneConverter) && (spec.PreserveUnknownFields == nil || *spec.PreserveUnknownFields)
-}
-
 func validateEnumStrings(fldPath *field.Path, value string, accepted []string, required bool) field.ErrorList {
 	if value == "" {
 		if required {
@@ -366,7 +362,7 @@ func ValidateCustomResourceDefinitionSpecUpdate(spec, oldSpec *apiextensions.Cus
 	// find out whether any schema had default before. Then we keep allowing it.
 	allowDefaults := utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceDefaulting) || specHasDefaults(oldSpec)
 
-	allErrs := validateCustomResourceDefinitionSpec(spec, requireRecognizedVersion, allowDefaults, conversionAndPreserveUnknownFields(oldSpec), fldPath)
+	allErrs := validateCustomResourceDefinitionSpec(spec, requireRecognizedVersion, allowDefaults, fldPath)
 
 	if established {
 		// these effect the storage and cannot be changed therefore

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

@@ -2044,82 +2044,6 @@ func TestValidateCustomResourceDefinitionUpdate(t *testing.T) {
 				invalid("spec", "conversion", "conversionReviewVersions"),
 			},
 		},
-		{
-			name: "webhookconfig: should accept preserveUnknownFields=true if set before",
-			resource: &apiextensions.CustomResourceDefinition{
-				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "42"},
-				Spec: apiextensions.CustomResourceDefinitionSpec{
-					Group: "group.com",
-					Scope: apiextensions.ResourceScope("Cluster"),
-					Names: apiextensions.CustomResourceDefinitionNames{
-						Plural:   "plural",
-						Singular: "singular",
-						Kind:     "Plural",
-						ListKind: "PluralList",
-					},
-					Versions: []apiextensions.CustomResourceDefinitionVersion{
-						{
-							Name:    "version",
-							Served:  true,
-							Storage: true,
-						},
-						{
-							Name:    "version2",
-							Served:  true,
-							Storage: false,
-						},
-					},
-					Conversion: &apiextensions.CustomResourceConversion{
-						Strategy: apiextensions.ConversionStrategyType("Webhook"),
-						WebhookClientConfig: &apiextensions.WebhookClientConfig{
-							URL: strPtr("https://example.com/webhook"),
-						},
-						ConversionReviewVersions: []string{"v1beta1"},
-					},
-					PreserveUnknownFields: pointer.BoolPtr(true),
-				},
-				Status: apiextensions.CustomResourceDefinitionStatus{
-					StoredVersions: []string{"version"},
-				},
-			},
-			old: &apiextensions.CustomResourceDefinition{
-				ObjectMeta: metav1.ObjectMeta{Name: "plural.group.com", ResourceVersion: "42"},
-				Spec: apiextensions.CustomResourceDefinitionSpec{
-					Group: "group.com",
-					Scope: apiextensions.ResourceScope("Cluster"),
-					Names: apiextensions.CustomResourceDefinitionNames{
-						Plural:   "plural",
-						Singular: "singular",
-						Kind:     "Plural",
-						ListKind: "PluralList",
-					},
-					Versions: []apiextensions.CustomResourceDefinitionVersion{
-						{
-							Name:    "version",
-							Served:  true,
-							Storage: true,
-						},
-						{
-							Name:    "version2",
-							Served:  true,
-							Storage: false,
-						},
-					},
-					Conversion: &apiextensions.CustomResourceConversion{
-						Strategy: apiextensions.ConversionStrategyType("Webhook"),
-						WebhookClientConfig: &apiextensions.WebhookClientConfig{
-							URL: strPtr("https://example.com/webhook"),
-						},
-						ConversionReviewVersions: []string{"v1beta1"},
-					},
-					PreserveUnknownFields: pointer.BoolPtr(true),
-				},
-				Status: apiextensions.CustomResourceDefinitionStatus{
-					StoredVersions: []string{"version"},
-				},
-			},
-			errors: []validationMatch{},
-		},
 		{
 			name: "unchanged",
 			old: &apiextensions.CustomResourceDefinition{