From 8d7264fb8efd92a398ab258236020f13facd2fb7 Mon Sep 17 00:00:00 2001
From: Antonio Ojea <antonio.ojea.garcia@gmail.com>
Date: Thu, 18 Aug 2022 16:35:00 +0200
Subject: [PATCH] regression test for exponential recursion bug on CRDs

---
 .../apiserver/crd_regression_test.go          | 139 ++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 test/integration/apiserver/crd_regression_test.go

diff --git a/test/integration/apiserver/crd_regression_test.go b/test/integration/apiserver/crd_regression_test.go
new file mode 100644
index 00000000000..3d7a9a850b5
--- /dev/null
+++ b/test/integration/apiserver/crd_regression_test.go
@@ -0,0 +1,139 @@
+/*
+Copyright 2022 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 apiserver
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/dynamic"
+	apiservertesting "k8s.io/kubernetes/cmd/kube-apiserver/app/testing"
+	"k8s.io/kubernetes/test/integration/framework"
+	"k8s.io/utils/pointer"
+)
+
+// Regression test for https://issues.k8s.io/109099
+func TestCRDExponentialRecursionBug(t *testing.T) {
+	server, err := apiservertesting.StartTestServer(t, apiservertesting.NewDefaultTestServerOptions(), nil, framework.SharedEtcd())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer server.TearDownFn()
+	config := server.ClientConfig
+
+	apiExtensionClient, err := clientset.NewForConfig(config)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dynamicClient, err := dynamic.NewForConfig(config)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	crd := &apiextensionsv1.CustomResourceDefinition{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "crontabs.stable.example.com",
+		},
+		Spec: apiextensionsv1.CustomResourceDefinitionSpec{
+			Group: "stable.example.com",
+			Scope: apiextensionsv1.ClusterScoped,
+			Names: apiextensionsv1.CustomResourceDefinitionNames{
+				Plural:   "crontabs",
+				Singular: "crontab",
+				Kind:     "CronTab",
+				ListKind: "CronTabList",
+			},
+			Versions: []apiextensionsv1.CustomResourceDefinitionVersion{
+				{
+					Name:    "v1beta1",
+					Served:  true,
+					Storage: true,
+					Schema: &apiextensionsv1.CustomResourceValidation{
+						OpenAPIV3Schema: &apiextensionsv1.JSONSchemaProps{
+							XPreserveUnknownFields: pointer.BoolPtr(true),
+							Type:                   "object",
+							Properties:             map[string]apiextensionsv1.JSONSchemaProps{},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	crd, err = apiExtensionClient.ApiextensionsV1().CustomResourceDefinitions().Create(context.TODO(), crd, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Wait until the CRD exist in discovery
+	err = wait.PollImmediate(100*time.Millisecond, 15*time.Second, func() (bool, error) {
+		groupResource, err := apiExtensionClient.Discovery().ServerResourcesForGroupVersion(crd.Spec.Group + "/" + crd.Spec.Versions[0].Name)
+		if err != nil {
+			return false, nil
+		}
+		for _, g := range groupResource.APIResources {
+			if g.Name == crd.Spec.Names.Plural {
+				return true, nil
+			}
+		}
+		return false, nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gvr := schema.GroupVersionResource{
+		Group:    crd.Spec.Group,
+		Version:  crd.Spec.Versions[0].Name,
+		Resource: crd.Spec.Names.Plural,
+	}
+
+	crClient := dynamicClient.Resource(gvr)
+
+	instance := &unstructured.Unstructured{
+		Object: map[string]interface{}{
+			"apiVersion": gvr.Group + "/" + gvr.Version,
+			"kind":       crd.Spec.Names.Kind,
+			"metadata": map[string]interface{}{
+				"name": "instanceame",
+			},
+			"spec": map[string]interface{}{},
+		},
+	}
+
+	// create a object with nested fields to trigger the bug
+	var m map[string]interface{}
+	m = instance.Object["spec"].(map[string]interface{})
+	for i := 0; i < 50; i++ {
+		m[fmt.Sprintf("field%d", i)] = map[string]interface{}{}
+		m = m[fmt.Sprintf("field%d", i)].(map[string]interface{})
+	}
+
+	_, err = crClient.Create(context.TODO(), instance, metav1.CreateOptions{})
+	if err != nil {
+		t.Errorf("Failed to create custom resource: %v", err)
+	}
+
+}