Merge pull request #52753 from munnerz/sample-controller

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

sample-controller: add example CRD controller

**What this PR does / why we need it**:

Adds a sample-controller example repository

fixes #52752

**Special notes for your reviewer**:

This is currently based on the sttts:sttts-codegen-scripts branch and should not be merged until that is (ref https://github.com/kubernetes/kubernetes/pull/52186)

**Release note**:

```
Add sample-controller repository
```

/cc @sttts @nikhita @colemickens

Kubernetes-commit: 9a7800f7d2efb88b397674672ac56f898826cf7c

vendor/k8s.io/apimachinery/pkg/conversion/helper.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2014 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 conversion
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// EnforcePtr ensures that obj is a pointer of some sort. Returns a reflect.Value
+// of the dereferenced pointer, ensuring that it is settable/addressable.
+// Returns an error if this is not possible.
+func EnforcePtr(obj interface{}) (reflect.Value, error) {
+	v := reflect.ValueOf(obj)
+	if v.Kind() != reflect.Ptr {
+		if v.Kind() == reflect.Invalid {
+			return reflect.Value{}, fmt.Errorf("expected pointer, but got invalid kind")
+		}
+		return reflect.Value{}, fmt.Errorf("expected pointer, but got %v type", v.Type())
+	}
+	if v.IsNil() {
+		return reflect.Value{}, fmt.Errorf("expected pointer, but got nil")
+	}
+	return v.Elem(), nil
+}