Add SetListOptionsDefaults for setting defaults on ListOptions

staging/src/k8s.io/apimachinery/pkg/apis/meta/internalversion/defaults.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package internalversion
+
+import metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+// SetListOptionsDefaults sets defaults on the provided ListOptions if applicable.
+//
+// TODO(#115478): once the watch-list fg is always on we register this function in the scheme (via AddTypeDefaultingFunc).
+// TODO(#115478): when the function is registered in the scheme remove all callers of this method.
+func SetListOptionsDefaults(obj *ListOptions, isWatchListFeatureEnabled bool) {
+	if !isWatchListFeatureEnabled {
+		return
+	}
+	if obj.SendInitialEvents != nil || len(obj.ResourceVersionMatch) != 0 {
+		return
+	}
+	legacy := obj.ResourceVersion == "" || obj.ResourceVersion == "0"
+	if obj.Watch && legacy {
+		turnOnInitialEvents := true
+		obj.SendInitialEvents = &turnOnInitialEvents
+		obj.ResourceVersionMatch = metav1.ResourceVersionMatchNotOlderThan
+	}
+}

staging/src/k8s.io/apimachinery/pkg/apis/meta/internalversion/defaults_test.go

@@ -0,0 +1,110 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package internalversion
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/fields"
+	"k8s.io/apimachinery/pkg/labels"
+)
+
+func TestSetListOptionsDefaults(t *testing.T) {
+	boolPtrFn := func(b bool) *bool {
+		return &b
+	}
+
+	scenarios := []struct {
+		name                    string
+		watchListFeatureEnabled bool
+		targetObj               ListOptions
+		expectedObj             ListOptions
+	}{
+		{
+			name:                    "no-op, RV doesn't match",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersion: "1"},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersion: "1"},
+		},
+		{
+			name:                    "no-op, SendInitialEvents set",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(true)},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(true)},
+		},
+		{
+			name:                    "no-op, ResourceVersionMatch set",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersionMatch: "m"},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersionMatch: "m"},
+		},
+		{
+			name:                    "no-op, Watch=false",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything()},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything()},
+		},
+		{
+			name:                    "defaults applied, match on empty RV",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(true), ResourceVersionMatch: metav1.ResourceVersionMatchNotOlderThan},
+		},
+		{
+			name:                    "defaults applied, match on RV=0",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersion: "0"},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersion: "0", SendInitialEvents: boolPtrFn(true), ResourceVersionMatch: metav1.ResourceVersionMatchNotOlderThan},
+		},
+		{
+			name:        "no-op, match on empty RV but watch-list fg is off",
+			targetObj:   ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true},
+			expectedObj: ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true},
+		},
+		{
+			name:                    "no-op, match on empty RV but SendInitialEvents is on",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(true)},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(true)},
+		},
+		{
+			name:                    "no-op, match on empty RV but SendInitialEvents is off",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(false)},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, SendInitialEvents: boolPtrFn(false)},
+		},
+		{
+			name:                    "no-op, match on empty RV but ResourceVersionMatch set",
+			watchListFeatureEnabled: true,
+			targetObj:               ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersionMatch: "m"},
+			expectedObj:             ListOptions{LabelSelector: labels.Everything(), FieldSelector: fields.Everything(), Watch: true, ResourceVersionMatch: "m"},
+		},
+	}
+
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			SetListOptionsDefaults(&scenario.targetObj, scenario.watchListFeatureEnabled)
+			if !apiequality.Semantic.DeepEqual(&scenario.expectedObj, &scenario.targetObj) {
+				t.Errorf("expected and defaulted objects are different:\n%s", cmp.Diff(&scenario.expectedObj, &scenario.targetObj))
+			}
+		})
+	}
+}

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

@@ -198,6 +198,7 @@ func DeleteCollection(r rest.CollectionDeleter, checkBody bool, scope *RequestSc
 			return
 		}
 
+		metainternalversion.SetListOptionsDefaults(&listOptions, utilfeature.DefaultFeatureGate.Enabled(features.WatchList))
 		if errs := metainternalversionvalidation.ValidateListOptions(&listOptions, utilfeature.DefaultFeatureGate.Enabled(features.WatchList)); len(errs) > 0 {
 			err := errors.NewInvalid(schema.GroupKind{Group: metav1.GroupName, Kind: "ListOptions"}, "", errs)
 			scope.err(err, w, req)

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

@@ -200,6 +200,7 @@ func ListResource(r rest.Lister, rw rest.Watcher, scope *RequestScope, forceWatc
 			return
 		}
 
+		metainternalversion.SetListOptionsDefaults(&opts, utilfeature.DefaultFeatureGate.Enabled(features.WatchList))
 		if errs := metainternalversionvalidation.ValidateListOptions(&opts, utilfeature.DefaultFeatureGate.Enabled(features.WatchList)); len(errs) > 0 {
 			err := errors.NewInvalid(schema.GroupKind{Group: metav1.GroupName, Kind: "ListOptions"}, "", errs)
 			scope.err(err, w, req)