rebase: update all k8s packages to 0.27.2

Signed-off-by: Niels de Vos <ndevos@ibm.com>

vendor/k8s.io/apimachinery/pkg/util/managedfields/scalehandler.go

@@ -0,0 +1,174 @@
+/*
+Copyright 2021 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 managedfields
+
+import (
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	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/managedfields/internal"
+	"sigs.k8s.io/structured-merge-diff/v4/fieldpath"
+)
+
+var (
+	scaleGroupVersion   = schema.GroupVersion{Group: "autoscaling", Version: "v1"}
+	replicasPathInScale = fieldpath.MakePathOrDie("spec", "replicas")
+)
+
+// ResourcePathMappings maps a group/version to its replicas path. The
+// assumption is that all the paths correspond to leaf fields.
+type ResourcePathMappings map[string]fieldpath.Path
+
+// ScaleHandler manages the conversion of managed fields between a main
+// resource and the scale subresource
+type ScaleHandler struct {
+	parentEntries []metav1.ManagedFieldsEntry
+	groupVersion  schema.GroupVersion
+	mappings      ResourcePathMappings
+}
+
+// NewScaleHandler creates a new ScaleHandler
+func NewScaleHandler(parentEntries []metav1.ManagedFieldsEntry, groupVersion schema.GroupVersion, mappings ResourcePathMappings) *ScaleHandler {
+	return &ScaleHandler{
+		parentEntries: parentEntries,
+		groupVersion:  groupVersion,
+		mappings:      mappings,
+	}
+}
+
+// ToSubresource filter the managed fields of the main resource and convert
+// them so that they can be handled by scale.
+// For the managed fields that have a replicas path it performs two changes:
+//  1. APIVersion is changed to the APIVersion of the scale subresource
+//  2. Replicas path of the main resource is transformed to the replicas path of
+//     the scale subresource
+func (h *ScaleHandler) ToSubresource() ([]metav1.ManagedFieldsEntry, error) {
+	managed, err := internal.DecodeManagedFields(h.parentEntries)
+	if err != nil {
+		return nil, err
+	}
+
+	f := fieldpath.ManagedFields{}
+	t := map[string]*metav1.Time{}
+	for manager, versionedSet := range managed.Fields() {
+		path, ok := h.mappings[string(versionedSet.APIVersion())]
+		// Skip the entry if the APIVersion is unknown
+		if !ok || path == nil {
+			continue
+		}
+
+		if versionedSet.Set().Has(path) {
+			newVersionedSet := fieldpath.NewVersionedSet(
+				fieldpath.NewSet(replicasPathInScale),
+				fieldpath.APIVersion(scaleGroupVersion.String()),
+				versionedSet.Applied(),
+			)
+
+			f[manager] = newVersionedSet
+			t[manager] = managed.Times()[manager]
+		}
+	}
+
+	return managedFieldsEntries(internal.NewManaged(f, t))
+}
+
+// ToParent merges `scaleEntries` with the entries of the main resource and
+// transforms them accordingly
+func (h *ScaleHandler) ToParent(scaleEntries []metav1.ManagedFieldsEntry) ([]metav1.ManagedFieldsEntry, error) {
+	decodedParentEntries, err := internal.DecodeManagedFields(h.parentEntries)
+	if err != nil {
+		return nil, err
+	}
+	parentFields := decodedParentEntries.Fields()
+
+	decodedScaleEntries, err := internal.DecodeManagedFields(scaleEntries)
+	if err != nil {
+		return nil, err
+	}
+	scaleFields := decodedScaleEntries.Fields()
+
+	f := fieldpath.ManagedFields{}
+	t := map[string]*metav1.Time{}
+
+	for manager, versionedSet := range parentFields {
+		// Get the main resource "replicas" path
+		path, ok := h.mappings[string(versionedSet.APIVersion())]
+		// Drop the entry if the APIVersion is unknown.
+		if !ok {
+			continue
+		}
+
+		// If the parent entry does not have the replicas path or it is nil, just
+		// keep it as it is. The path is nil for Custom Resources without scale
+		// subresource.
+		if path == nil || !versionedSet.Set().Has(path) {
+			f[manager] = versionedSet
+			t[manager] = decodedParentEntries.Times()[manager]
+			continue
+		}
+
+		if _, ok := scaleFields[manager]; !ok {
+			// "Steal" the replicas path from the main resource entry
+			newSet := versionedSet.Set().Difference(fieldpath.NewSet(path))
+
+			if !newSet.Empty() {
+				newVersionedSet := fieldpath.NewVersionedSet(
+					newSet,
+					versionedSet.APIVersion(),
+					versionedSet.Applied(),
+				)
+				f[manager] = newVersionedSet
+				t[manager] = decodedParentEntries.Times()[manager]
+			}
+		} else {
+			// Field wasn't stolen, let's keep the entry as it is.
+			f[manager] = versionedSet
+			t[manager] = decodedParentEntries.Times()[manager]
+			delete(scaleFields, manager)
+		}
+	}
+
+	for manager, versionedSet := range scaleFields {
+		if !versionedSet.Set().Has(replicasPathInScale) {
+			continue
+		}
+		newVersionedSet := fieldpath.NewVersionedSet(
+			fieldpath.NewSet(h.mappings[h.groupVersion.String()]),
+			fieldpath.APIVersion(h.groupVersion.String()),
+			versionedSet.Applied(),
+		)
+		f[manager] = newVersionedSet
+		t[manager] = decodedParentEntries.Times()[manager]
+	}
+
+	return managedFieldsEntries(internal.NewManaged(f, t))
+}
+
+func managedFieldsEntries(entries internal.ManagedInterface) ([]metav1.ManagedFieldsEntry, error) {
+	obj := &unstructured.Unstructured{Object: map[string]interface{}{}}
+	if err := internal.EncodeObjectManagedFields(obj, entries); err != nil {
+		return nil, err
+	}
+	accessor, err := meta.Accessor(obj)
+	if err != nil {
+		panic(fmt.Sprintf("couldn't get accessor: %v", err))
+	}
+	return accessor.GetManagedFields(), nil
+}