Merge pull request #54957 from apelisse/update-kube-openapi

Automatic merge from submit-queue (batch tested with PRs 55004, 54957). 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>.

Update kube-openapi to use validation

**What this PR does / why we need it**: Moves openapi validation code to kube-openapi, so that we can move the rest of the code to apimachinery repository, so that later we can use it from both the client and the server.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #Nothing

**Special notes for your reviewer**:

**Release note**:
```release-note
NONE
```

Kubernetes-commit: 55e216f56eac0082acc6be655d9ae09cf9ba38a8

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/patch.go

@@ -22,6 +22,7 @@ import (
 	"sort"
 	"strings"
 
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/util/json"
 	"k8s.io/apimachinery/pkg/util/mergepatch"
 	forkedjson "k8s.io/apimachinery/third_party/forked/golang/json"
@@ -515,6 +516,9 @@ func normalizeSliceOrder(toSort, order []interface{}, mergeKey string, kind refl
 			return nil, err
 		}
 		toSort, toDelete, err = extractToDeleteItems(toSort)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	sort.SliceStable(toSort, func(i, j int) bool {
@@ -554,7 +558,13 @@ func diffLists(original, modified []interface{}, t reflect.Type, mergeKey string
 	switch kind {
 	case reflect.Map:
 		patchList, deleteList, err = diffListsOfMaps(original, modified, t, mergeKey, diffOptions)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 		patchList, err = normalizeSliceOrder(patchList, modified, mergeKey, kind)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 		orderSame, err := isOrderSame(original, modified, mergeKey)
 		if err != nil {
 			return nil, nil, nil, err
@@ -580,6 +590,9 @@ func diffLists(original, modified []interface{}, t reflect.Type, mergeKey string
 		return nil, nil, nil, mergepatch.ErrNoListOfLists
 	default:
 		patchList, deleteList, err = diffListsOfScalars(original, modified, diffOptions)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 		patchList, err = normalizeSliceOrder(patchList, modified, mergeKey, kind)
 		// generate the setElementOrder list when there are content changes or order changes
 		if diffOptions.SetElementOrder && ((!diffOptions.IgnoreDeletions && len(deleteList) > 0) ||
@@ -816,7 +829,7 @@ func handleUnmarshal(j []byte) (map[string]interface{}, error) {
 	return m, nil
 }
 
-// StrategicMergePatch applies a strategic merge patch. The original and patch documents
+// StrategicMergeMapPatch applies a strategic merge patch. The original and patch documents
 // must be JSONMap. A patch can be created from an original and modified document by
 // calling CreateTwoWayMergeMapPatch.
 // Warning: the original and patch JSONMap objects are mutated by this function and should not be reused.
@@ -825,6 +838,17 @@ func StrategicMergeMapPatch(original, patch JSONMap, dataStruct interface{}) (JS
 	if err != nil {
 		return nil, err
 	}
+
+	// We need the go struct tags `patchMergeKey` and `patchStrategy` for fields that support a strategic merge patch.
+	// For native resources, we can easily figure out these tags since we know the fields.
+
+	// Because custom resources are decoded as Unstructured and because we're missing the metadata about how to handle
+	// each field in a strategic merge patch, we can't find the go struct tags. Hence, we can't easily  do a strategic merge
+	// for custom resources. So we should fail fast and return an error.
+	if _, ok := dataStruct.(*unstructured.Unstructured); ok {
+		return nil, mergepatch.ErrUnsupportedStrategicMergePatchFormat
+	}
+
 	mergeOptions := MergeOptions{
 		MergeParallelList:    true,
 		IgnoreUnmatchedNulls: true,
@@ -1520,7 +1544,7 @@ func findMapInSliceBasedOnKeyValue(m []interface{}, key string, value interface{
 	for k, v := range m {
 		typedV, ok := v.(map[string]interface{})
 		if !ok {
-			return nil, 0, false, fmt.Errorf("value for key %v is not a map.", k)
+			return nil, 0, false, fmt.Errorf("value for key %v is not a map", k)
 		}
 
 		valueToMatch, ok := typedV[key]
@@ -1540,7 +1564,7 @@ func sortMergeListsByName(mapJSON []byte, dataStruct interface{}) ([]byte, error
 	var m map[string]interface{}
 	err := json.Unmarshal(mapJSON, &m)
 	if err != nil {
-		return nil, err
+		return nil, mergepatch.ErrBadJSONDoc
 	}
 
 	newM, err := sortMergeListsByNameMap(m, reflect.TypeOf(dataStruct))