rebase: bump k8s.io/kubernetes from 1.26.2 to 1.27.2

Bumps [k8s.io/kubernetes](https://github.com/kubernetes/kubernetes) from 1.26.2 to 1.27.2.
- [Release notes](https://github.com/kubernetes/kubernetes/releases)
- [Commits](https://github.com/kubernetes/kubernetes/compare/v1.26.2...v1.27.2)

---
updated-dependencies:
- dependency-name: k8s.io/kubernetes
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/k8s.io/kube-openapi/pkg/cached/cache.go

@@ -0,0 +1,264 @@
+/*
+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 cache provides a cache mechanism based on etags to lazily
+// build, and/or cache results from expensive operation such that those
+// operations are not repeated unnecessarily. The operations can be
+// created as a tree, and replaced dynamically as needed.
+//
+// # Dependencies and types of caches
+//
+// This package uses a source/transform/sink model of caches to build
+// the dependency tree, and can be used as follows:
+//   - [NewSource]: A source cache that recomputes the content every time.
+//   - [NewStaticSource]: A source cache that always produces the
+//     same content, it is only called once.
+//   - [NewTransformer]: A cache that transforms data from one format to
+//     another. It's only refreshed when the source changes.
+//   - [NewMerger]: A cache that aggregates multiple caches into one.
+//     It's only refreshed when the source changes.
+//   - [Replaceable]: A cache adapter that can be atomically
+//     replaced with a new one, and saves the previous results in case an
+//     error pops-up.
+//
+// # Atomicity
+//
+// Most of the operations are not atomic/thread-safe, except for
+// [Replaceable.Replace] which can be performed while the objects
+// are being read.
+//
+// # Etags
+//
+// Etags in this library is a cache version identifier. It doesn't
+// necessarily strictly match to the semantics of http `etags`, but are
+// somewhat inspired from it and function with the same principles.
+// Hashing the content is a good way to guarantee that your function is
+// never going to be called spuriously. In Kubernetes world, this could
+// be a `resourceVersion`, this can be an actual etag, a hash, a UUID
+// (if the cache always changes), or even a made-up string when the
+// content of the cache never changes.
+package cached
+
+import (
+	"fmt"
+	"sync/atomic"
+)
+
+// Result is the content returned from a call to a cache. It can either
+// be created with [NewResultOK] if the call was a success, or
+// [NewResultErr] if the call resulted in an error.
+type Result[T any] struct {
+	Data T
+	Etag string
+	Err  error
+}
+
+// NewResultOK creates a new [Result] for a successful operation.
+func NewResultOK[T any](data T, etag string) Result[T] {
+	return Result[T]{
+		Data: data,
+		Etag: etag,
+	}
+}
+
+// NewResultErr creates a new [Result] when an error has happened.
+func NewResultErr[T any](err error) Result[T] {
+	return Result[T]{
+		Err: err,
+	}
+}
+
+// Result can be treated as a [Data] if necessary.
+func (r Result[T]) Get() Result[T] {
+	return r
+}
+
+// Data is a cache that performs an action whose result data will be
+// cached. It also returns an "etag" identifier to version the cache, so
+// that the caller can know if they have the most recent version of the
+// cache (and can decide to cache some operation based on that).
+//
+// The [NewMerger] and [NewTransformer] automatically handle
+// that for you by checking if the etag is updated before calling the
+// merging or transforming function.
+type Data[T any] interface {
+	// Returns the cached data, as well as an "etag" to identify the
+	// version of the cache, or an error if something happened.
+	Get() Result[T]
+}
+
+// T is the source type, V is the destination type.
+type merger[K comparable, T, V any] struct {
+	mergeFn      func(map[K]Result[T]) Result[V]
+	caches       map[K]Data[T]
+	cacheResults map[K]Result[T]
+	result       Result[V]
+}
+
+// NewMerger creates a new merge cache, a cache that merges the result
+// of other caches. The function only gets called if any of the
+// dependency has changed.
+//
+// If any of the dependency returned an error before, or any of the
+// dependency returned an error this time, or if the mergeFn failed
+// before, then the function is reran.
+//
+// The caches and results are mapped by K so that associated data can be
+// retrieved. The map of dependencies can not be modified after
+// creation, and a new merger should be created (and probably replaced
+// using a [Replaceable]).
+//
+// Note that this assumes there is no "partial" merge, the merge
+// function will remerge all the dependencies together everytime. Since
+// the list of dependencies is constant, there is no way to save some
+// partial merge information either.
+func NewMerger[K comparable, T, V any](mergeFn func(results map[K]Result[T]) Result[V], caches map[K]Data[T]) Data[V] {
+	return &merger[K, T, V]{
+		mergeFn: mergeFn,
+		caches:  caches,
+	}
+}
+
+func (c *merger[K, T, V]) prepareResults() map[K]Result[T] {
+	cacheResults := make(map[K]Result[T], len(c.caches))
+	for key, cache := range c.caches {
+		cacheResults[key] = cache.Get()
+	}
+	return cacheResults
+}
+
+// Rerun if:
+//   - The last run resulted in an error
+//   - Any of the dependency previously returned an error
+//   - Any of the dependency just returned an error
+//   - Any of the dependency's etag changed
+func (c *merger[K, T, V]) needsRunning(results map[K]Result[T]) bool {
+	if c.cacheResults == nil {
+		return true
+	}
+	if c.result.Err != nil {
+		return true
+	}
+	if len(results) != len(c.cacheResults) {
+		panic(fmt.Errorf("invalid number of results: %v (expected %v)", len(results), len(c.cacheResults)))
+	}
+	for key, oldResult := range c.cacheResults {
+		newResult, ok := results[key]
+		if !ok {
+			panic(fmt.Errorf("unknown cache entry: %v", key))
+		}
+
+		if newResult.Etag != oldResult.Etag || newResult.Err != nil || oldResult.Err != nil {
+			return true
+		}
+	}
+	return false
+}
+
+func (c *merger[K, T, V]) Get() Result[V] {
+	cacheResults := c.prepareResults()
+	if c.needsRunning(cacheResults) {
+		c.cacheResults = cacheResults
+		c.result = c.mergeFn(c.cacheResults)
+	}
+	return c.result
+}
+
+type transformerCacheKeyType struct{}
+
+// NewTransformer creates a new cache that transforms the result of
+// another cache. The transformFn will only be called if the source
+// cache has updated the output, otherwise, the cached result will be
+// returned.
+//
+// If the dependency returned an error before, or it returns an error
+// this time, or if the transformerFn failed before, the function is
+// reran.
+func NewTransformer[T, V any](transformerFn func(Result[T]) Result[V], source Data[T]) Data[V] {
+	return NewMerger(func(caches map[transformerCacheKeyType]Result[T]) Result[V] {
+		cache, ok := caches[transformerCacheKeyType{}]
+		if len(caches) != 1 || !ok {
+			panic(fmt.Errorf("invalid cache for transformer cache: %v", caches))
+		}
+		return transformerFn(cache)
+	}, map[transformerCacheKeyType]Data[T]{
+		{}: source,
+	})
+}
+
+// NewSource creates a new cache that generates some data. This
+// will always be called since we don't know the origin of the data and
+// if it needs to be updated or not.
+func NewSource[T any](sourceFn func() Result[T]) Data[T] {
+	c := source[T](sourceFn)
+	return &c
+}
+
+type source[T any] func() Result[T]
+
+func (c *source[T]) Get() Result[T] {
+	return (*c)()
+}
+
+// NewStaticSource creates a new cache that always generates the
+// same data. This will only be called once (lazily).
+func NewStaticSource[T any](staticFn func() Result[T]) Data[T] {
+	return &static[T]{
+		fn: staticFn,
+	}
+}
+
+type static[T any] struct {
+	fn     func() Result[T]
+	result *Result[T]
+}
+
+func (c *static[T]) Get() Result[T] {
+	if c.result == nil {
+		result := c.fn()
+		c.result = &result
+	}
+	return *c.result
+}
+
+// Replaceable is a cache that carries the result even when the
+// cache is replaced. The cache can be replaced atomically (without any
+// lock held). This is the type that should typically be stored in
+// structs.
+type Replaceable[T any] struct {
+	cache  atomic.Pointer[Data[T]]
+	result *Result[T]
+}
+
+// Get retrieves the data from the underlying source. [Replaceable]
+// implements the [Data] interface itself. This is a pass-through
+// that calls the most recent underlying cache. If the cache fails but
+// previously had returned a success, that success will be returned
+// instead. If the cache fails but we never returned a success, that
+// failure is returned.
+func (c *Replaceable[T]) Get() Result[T] {
+	result := (*c.cache.Load()).Get()
+	if result.Err != nil && c.result != nil && c.result.Err == nil {
+		return *c.result
+	}
+	c.result = &result
+	return *c.result
+}
+
+// Replace changes the cache in a thread-safe way.
+func (c *Replaceable[T]) Replace(cache Data[T]) {
+	c.cache.Swap(&cache)
+}