rebase: update all k8s packages to 0.27.2

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

vendor/k8s.io/client-go/discovery/aggregated_discovery.go

@@ -24,19 +24,36 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )
 
+// StaleGroupVersionError encasulates failed GroupVersion marked "stale"
+// in the returned AggregatedDiscovery format.
+type StaleGroupVersionError struct {
+	gv schema.GroupVersion
+}
+
+func (s StaleGroupVersionError) Error() string {
+	return fmt.Sprintf("stale GroupVersion discovery: %v", s.gv)
+}
+
 // SplitGroupsAndResources transforms "aggregated" discovery top-level structure into
 // the previous "unaggregated" discovery groups and resources.
-func SplitGroupsAndResources(aggregatedGroups apidiscovery.APIGroupDiscoveryList) (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList) {
+func SplitGroupsAndResources(aggregatedGroups apidiscovery.APIGroupDiscoveryList) (
+	*metav1.APIGroupList,
+	map[schema.GroupVersion]*metav1.APIResourceList,
+	map[schema.GroupVersion]error) {
 	// Aggregated group list will contain the entirety of discovery, including
-	// groups, versions, and resources.
+	// groups, versions, and resources. GroupVersions marked "stale" are failed.
 	groups := []*metav1.APIGroup{}
+	failedGVs := map[schema.GroupVersion]error{}
 	resourcesByGV := map[schema.GroupVersion]*metav1.APIResourceList{}
 	for _, aggGroup := range aggregatedGroups.Items {
-		group, resources := convertAPIGroup(aggGroup)
+		group, resources, failed := convertAPIGroup(aggGroup)
 		groups = append(groups, group)
 		for gv, resourceList := range resources {
 			resourcesByGV[gv] = resourceList
 		}
+		for gv, err := range failed {
+			failedGVs[gv] = err
+		}
 	}
 	// Transform slice of groups to group list before returning.
 	groupList := &metav1.APIGroupList{}
@@ -44,65 +61,94 @@ func SplitGroupsAndResources(aggregatedGroups apidiscovery.APIGroupDiscoveryList
 	for _, group := range groups {
 		groupList.Groups = append(groupList.Groups, *group)
 	}
-	return groupList, resourcesByGV
+	return groupList, resourcesByGV, failedGVs
 }
 
 // convertAPIGroup tranforms an "aggregated" APIGroupDiscovery to an "legacy" APIGroup,
 // also returning the map of APIResourceList for resources within GroupVersions.
-func convertAPIGroup(g apidiscovery.APIGroupDiscovery) (*metav1.APIGroup, map[schema.GroupVersion]*metav1.APIResourceList) {
+func convertAPIGroup(g apidiscovery.APIGroupDiscovery) (
+	*metav1.APIGroup,
+	map[schema.GroupVersion]*metav1.APIResourceList,
+	map[schema.GroupVersion]error) {
 	// Iterate through versions to convert to group and resources.
 	group := &metav1.APIGroup{}
 	gvResources := map[schema.GroupVersion]*metav1.APIResourceList{}
+	failedGVs := map[schema.GroupVersion]error{}
 	group.Name = g.ObjectMeta.Name
-	for i, v := range g.Versions {
-		version := metav1.GroupVersionForDiscovery{}
+	for _, v := range g.Versions {
 		gv := schema.GroupVersion{Group: g.Name, Version: v.Version}
+		if v.Freshness == apidiscovery.DiscoveryFreshnessStale {
+			failedGVs[gv] = StaleGroupVersionError{gv: gv}
+			continue
+		}
+		version := metav1.GroupVersionForDiscovery{}
 		version.GroupVersion = gv.String()
 		version.Version = v.Version
 		group.Versions = append(group.Versions, version)
-		if i == 0 {
+		// PreferredVersion is first non-stale Version
+		if group.PreferredVersion == (metav1.GroupVersionForDiscovery{}) {
 			group.PreferredVersion = version
 		}
 		resourceList := &metav1.APIResourceList{}
 		resourceList.GroupVersion = gv.String()
 		for _, r := range v.Resources {
-			resource := convertAPIResource(r)
-			resourceList.APIResources = append(resourceList.APIResources, resource)
+			resource, err := convertAPIResource(r)
+			if err == nil {
+				resourceList.APIResources = append(resourceList.APIResources, resource)
+			}
 			// Subresources field in new format get transformed into full APIResources.
+			// It is possible a partial result with an error was returned to be used
+			// as the parent resource for the subresource.
 			for _, subresource := range r.Subresources {
-				sr := convertAPISubresource(resource, subresource)
-				resourceList.APIResources = append(resourceList.APIResources, sr)
+				sr, err := convertAPISubresource(resource, subresource)
+				if err == nil {
+					resourceList.APIResources = append(resourceList.APIResources, sr)
+				}
 			}
 		}
 		gvResources[gv] = resourceList
 	}
-	return group, gvResources
+	return group, gvResources, failedGVs
 }
 
-// convertAPIResource tranforms a APIResourceDiscovery to an APIResource.
-func convertAPIResource(in apidiscovery.APIResourceDiscovery) metav1.APIResource {
-	return metav1.APIResource{
+// convertAPIResource tranforms a APIResourceDiscovery to an APIResource. We are
+// resilient to missing GVK, since this resource might be the parent resource
+// for a subresource. If the parent is missing a GVK, it is not returned in
+// discovery, and the subresource MUST have the GVK.
+func convertAPIResource(in apidiscovery.APIResourceDiscovery) (metav1.APIResource, error) {
+	result := metav1.APIResource{
 		Name:         in.Resource,
 		SingularName: in.SingularResource,
 		Namespaced:   in.Scope == apidiscovery.ScopeNamespace,
-		Group:        in.ResponseKind.Group,
-		Version:      in.ResponseKind.Version,
-		Kind:         in.ResponseKind.Kind,
 		Verbs:        in.Verbs,
 		ShortNames:   in.ShortNames,
 		Categories:   in.Categories,
 	}
+	var err error
+	if in.ResponseKind != nil {
+		result.Group = in.ResponseKind.Group
+		result.Version = in.ResponseKind.Version
+		result.Kind = in.ResponseKind.Kind
+	} else {
+		err = fmt.Errorf("discovery resource %s missing GVK", in.Resource)
+	}
+	// Can return partial result with error, which can be the parent for a
+	// subresource. Do not add this result to the returned discovery resources.
+	return result, err
 }
 
 // convertAPISubresource tranforms a APISubresourceDiscovery to an APIResource.
-func convertAPISubresource(parent metav1.APIResource, in apidiscovery.APISubresourceDiscovery) metav1.APIResource {
-	return metav1.APIResource{
-		Name:         fmt.Sprintf("%s/%s", parent.Name, in.Subresource),
-		SingularName: parent.SingularName,
-		Namespaced:   parent.Namespaced,
-		Group:        in.ResponseKind.Group,
-		Version:      in.ResponseKind.Version,
-		Kind:         in.ResponseKind.Kind,
-		Verbs:        in.Verbs,
+func convertAPISubresource(parent metav1.APIResource, in apidiscovery.APISubresourceDiscovery) (metav1.APIResource, error) {
+	result := metav1.APIResource{}
+	if in.ResponseKind == nil {
+		return result, fmt.Errorf("subresource %s/%s missing GVK", parent.Name, in.Subresource)
 	}
+	result.Name = fmt.Sprintf("%s/%s", parent.Name, in.Subresource)
+	result.SingularName = parent.SingularName
+	result.Namespaced = parent.Namespaced
+	result.Group = in.ResponseKind.Group
+	result.Version = in.ResponseKind.Version
+	result.Kind = in.ResponseKind.Kind
+	result.Verbs = in.Verbs
+	return result, nil
 }

vendor/k8s.io/client-go/discovery/cached/memory/memcache.go

@@ -33,6 +33,7 @@ import (
 	"k8s.io/client-go/openapi"
 	cachedopenapi "k8s.io/client-go/openapi/cached"
 	restclient "k8s.io/client-go/rest"
+	"k8s.io/klog/v2"
 )
 
 type cacheEntry struct {
@@ -61,6 +62,15 @@ var (
 	ErrCacheNotFound = errors.New("not found")
 )
 
+// Server returning empty ResourceList for Group/Version.
+type emptyResponseError struct {
+	gv string
+}
+
+func (e *emptyResponseError) Error() string {
+	return fmt.Sprintf("received empty response for: %s", e.gv)
+}
+
 var _ discovery.CachedDiscoveryInterface = &memCacheClient{}
 
 // isTransientConnectionError checks whether given error is "Connection refused" or
@@ -103,7 +113,13 @@ func (d *memCacheClient) ServerResourcesForGroupVersion(groupVersion string) (*m
 	if cachedVal.err != nil && isTransientError(cachedVal.err) {
 		r, err := d.serverResourcesForGroupVersion(groupVersion)
 		if err != nil {
-			utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", groupVersion, err))
+			// Don't log "empty response" as an error; it is a common response for metrics.
+			if _, emptyErr := err.(*emptyResponseError); emptyErr {
+				// Log at same verbosity as disk cache.
+				klog.V(3).Infof("%v", err)
+			} else {
+				utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", groupVersion, err))
+			}
 		}
 		cachedVal = &cacheEntry{r, err}
 		d.groupToServerResources[groupVersion] = cachedVal
@@ -120,32 +136,38 @@ func (d *memCacheClient) ServerGroupsAndResources() ([]*metav1.APIGroup, []*meta
 // GroupsAndMaybeResources returns the list of APIGroups, and possibly the map of group/version
 // to resources. The returned groups will never be nil, but the resources map can be nil
 // if there are no cached resources.
-func (d *memCacheClient) GroupsAndMaybeResources() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, error) {
+func (d *memCacheClient) GroupsAndMaybeResources() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, map[schema.GroupVersion]error, error) {
 	d.lock.Lock()
 	defer d.lock.Unlock()
 
 	if !d.cacheValid {
 		if err := d.refreshLocked(); err != nil {
-			return nil, nil, err
+			return nil, nil, nil, err
 		}
 	}
 	// Build the resourceList from the cache?
 	var resourcesMap map[schema.GroupVersion]*metav1.APIResourceList
+	var failedGVs map[schema.GroupVersion]error
 	if d.receivedAggregatedDiscovery && len(d.groupToServerResources) > 0 {
 		resourcesMap = map[schema.GroupVersion]*metav1.APIResourceList{}
+		failedGVs = map[schema.GroupVersion]error{}
 		for gv, cacheEntry := range d.groupToServerResources {
 			groupVersion, err := schema.ParseGroupVersion(gv)
 			if err != nil {
-				return nil, nil, fmt.Errorf("failed to parse group version (%v): %v", gv, err)
+				return nil, nil, nil, fmt.Errorf("failed to parse group version (%v): %v", gv, err)
+			}
+			if cacheEntry.err != nil {
+				failedGVs[groupVersion] = cacheEntry.err
+			} else {
+				resourcesMap[groupVersion] = cacheEntry.resourceList
 			}
-			resourcesMap[groupVersion] = cacheEntry.resourceList
 		}
 	}
-	return d.groupList, resourcesMap, nil
+	return d.groupList, resourcesMap, failedGVs, nil
 }
 
 func (d *memCacheClient) ServerGroups() (*metav1.APIGroupList, error) {
-	groups, _, err := d.GroupsAndMaybeResources()
+	groups, _, _, err := d.GroupsAndMaybeResources()
 	if err != nil {
 		return nil, err
 	}
@@ -219,7 +241,8 @@ func (d *memCacheClient) refreshLocked() error {
 
 	if ad, ok := d.delegate.(discovery.AggregatedDiscoveryInterface); ok {
 		var resources map[schema.GroupVersion]*metav1.APIResourceList
-		gl, resources, err = ad.GroupsAndMaybeResources()
+		var failedGVs map[schema.GroupVersion]error
+		gl, resources, failedGVs, err = ad.GroupsAndMaybeResources()
 		if resources != nil && err == nil {
 			// Cache the resources.
 			d.groupToServerResources = map[string]*cacheEntry{}
@@ -227,6 +250,10 @@ func (d *memCacheClient) refreshLocked() error {
 			for gv, resources := range resources {
 				d.groupToServerResources[gv.String()] = &cacheEntry{resources, nil}
 			}
+			// Cache GroupVersion discovery errors
+			for gv, err := range failedGVs {
+				d.groupToServerResources[gv.String()] = &cacheEntry{nil, err}
+			}
 			d.receivedAggregatedDiscovery = true
 			d.cacheValid = true
 			return nil
@@ -252,7 +279,13 @@ func (d *memCacheClient) refreshLocked() error {
 
 				r, err := d.serverResourcesForGroupVersion(gv)
 				if err != nil {
-					utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", gv, err))
+					// Don't log "empty response" as an error; it is a common response for metrics.
+					if _, emptyErr := err.(*emptyResponseError); emptyErr {
+						// Log at same verbosity as disk cache.
+						klog.V(3).Infof("%v", err)
+					} else {
+						utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", gv, err))
+					}
 				}
 
 				resultLock.Lock()
@@ -274,7 +307,7 @@ func (d *memCacheClient) serverResourcesForGroupVersion(groupVersion string) (*m
 		return r, err
 	}
 	if len(r.APIResources) == 0 {
-		return r, fmt.Errorf("Got empty response for: %v", groupVersion)
+		return r, &emptyResponseError{gv: groupVersion}
 	}
 	return r, nil
 }

vendor/k8s.io/client-go/discovery/discovery_client.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"mime"
 	"net/http"
 	"net/url"
 	"sort"
@@ -58,8 +59,9 @@ const (
 	defaultBurst = 300
 
 	AcceptV1 = runtime.ContentTypeJSON
-	// Aggregated discovery content-type (currently v2beta1). NOTE: Currently, we are assuming the order
-	// for "g", "v", and "as" from the server. We can only compare this string if we can make that assumption.
+	// Aggregated discovery content-type (v2beta1). NOTE: content-type parameters
+	// MUST be ordered (g, v, as) for server in "Accept" header (BUT we are resilient
+	// to ordering when comparing returned values in "Content-Type" header).
 	AcceptV2Beta1 = runtime.ContentTypeJSON + ";" + "g=apidiscovery.k8s.io;v=v2beta1;as=APIGroupDiscoveryList"
 	// Prioritize aggregated discovery by placing first in the order of discovery accept types.
 	acceptDiscoveryFormats = AcceptV2Beta1 + "," + AcceptV1
@@ -86,7 +88,7 @@ type DiscoveryInterface interface {
 type AggregatedDiscoveryInterface interface {
 	DiscoveryInterface
 
-	GroupsAndMaybeResources() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, error)
+	GroupsAndMaybeResources() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, map[schema.GroupVersion]error, error)
 }
 
 // CachedDiscoveryInterface is a DiscoveryInterface with cache invalidation and freshness.
@@ -186,18 +188,23 @@ func apiVersionsToAPIGroup(apiVersions *metav1.APIVersions) (apiGroup metav1.API
 // and resources from /api and /apis (either aggregated or not). Legacy groups
 // must be ordered first. The server will either return both endpoints (/api, /apis)
 // as aggregated discovery format or legacy format. For safety, resources will only
-// be returned if both endpoints returned resources.
-func (d *DiscoveryClient) GroupsAndMaybeResources() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, error) {
+// be returned if both endpoints returned resources. Returned "failedGVs" can be
+// empty, but will only be nil in the case an error is returned.
+func (d *DiscoveryClient) GroupsAndMaybeResources() (
+	*metav1.APIGroupList,
+	map[schema.GroupVersion]*metav1.APIResourceList,
+	map[schema.GroupVersion]error,
+	error) {
 	// Legacy group ordered first (there is only one -- core/v1 group). Returned groups must
 	// be non-nil, but it could be empty. Returned resources, apiResources map could be nil.
-	groups, resources, err := d.downloadLegacy()
+	groups, resources, failedGVs, err := d.downloadLegacy()
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, nil, err
 	}
 	// Discovery groups and (possibly) resources downloaded from /apis.
-	apiGroups, apiResources, aerr := d.downloadAPIs()
+	apiGroups, apiResources, failedApisGVs, aerr := d.downloadAPIs()
 	if aerr != nil {
-		return nil, nil, aerr
+		return nil, nil, nil, aerr
 	}
 	// Merge apis groups into the legacy groups.
 	for _, group := range apiGroups.Groups {
@@ -211,14 +218,23 @@ func (d *DiscoveryClient) GroupsAndMaybeResources() (*metav1.APIGroupList, map[s
 	} else if resources != nil {
 		resources = nil
 	}
-	return groups, resources, err
+	// Merge failed GroupVersions from /api and /apis
+	for gv, err := range failedApisGVs {
+		failedGVs[gv] = err
+	}
+	return groups, resources, failedGVs, err
 }
 
 // downloadLegacy returns the discovery groups and possibly resources
 // for the legacy v1 GVR at /api, or an error if one occurred. It is
 // possible for the resource map to be nil if the server returned
-// the unaggregated discovery.
-func (d *DiscoveryClient) downloadLegacy() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, error) {
+// the unaggregated discovery. Returned "failedGVs" can be empty, but
+// will only be nil in the case of a returned error.
+func (d *DiscoveryClient) downloadLegacy() (
+	*metav1.APIGroupList,
+	map[schema.GroupVersion]*metav1.APIResourceList,
+	map[schema.GroupVersion]error,
+	error) {
 	accept := acceptDiscoveryFormats
 	if d.UseLegacyDiscovery {
 		accept = AcceptV1
@@ -230,48 +246,55 @@ func (d *DiscoveryClient) downloadLegacy() (*metav1.APIGroupList, map[schema.Gro
 		Do(context.TODO()).
 		ContentType(&responseContentType).
 		Raw()
-	// Special error handling for 403 or 404 to be compatible with older v1.0 servers.
-	// Return empty group list to be merged with /apis.
-	if err != nil && !errors.IsNotFound(err) && !errors.IsForbidden(err) {
-		return nil, nil, err
-	}
-	if err != nil && (errors.IsNotFound(err) || errors.IsForbidden(err)) {
-		return &metav1.APIGroupList{}, nil, nil
+	apiGroupList := &metav1.APIGroupList{}
+	failedGVs := map[schema.GroupVersion]error{}
+	if err != nil {
+		// Tolerate 404, since aggregated api servers can return it.
+		if errors.IsNotFound(err) {
+			// Return empty structures and no error.
+			emptyGVMap := map[schema.GroupVersion]*metav1.APIResourceList{}
+			return apiGroupList, emptyGVMap, failedGVs, nil
+		} else {
+			return nil, nil, nil, err
+		}
 	}
 
-	apiGroupList := &metav1.APIGroupList{}
 	var resourcesByGV map[schema.GroupVersion]*metav1.APIResourceList
 	// Switch on content-type server responded with: aggregated or unaggregated.
-	switch responseContentType {
-	case AcceptV1:
+	switch {
+	case isV2Beta1ContentType(responseContentType):
+		var aggregatedDiscovery apidiscovery.APIGroupDiscoveryList
+		err = json.Unmarshal(body, &aggregatedDiscovery)
+		if err != nil {
+			return nil, nil, nil, err
+		}
+		apiGroupList, resourcesByGV, failedGVs = SplitGroupsAndResources(aggregatedDiscovery)
+	default:
+		// Default is unaggregated discovery v1.
 		var v metav1.APIVersions
 		err = json.Unmarshal(body, &v)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, nil, err
 		}
 		apiGroup := metav1.APIGroup{}
 		if len(v.Versions) != 0 {
 			apiGroup = apiVersionsToAPIGroup(&v)
 		}
 		apiGroupList.Groups = []metav1.APIGroup{apiGroup}
-	case AcceptV2Beta1:
-		var aggregatedDiscovery apidiscovery.APIGroupDiscoveryList
-		err = json.Unmarshal(body, &aggregatedDiscovery)
-		if err != nil {
-			return nil, nil, err
-		}
-		apiGroupList, resourcesByGV = SplitGroupsAndResources(aggregatedDiscovery)
-	default:
-		return nil, nil, fmt.Errorf("Unknown discovery response content-type: %s", responseContentType)
 	}
 
-	return apiGroupList, resourcesByGV, nil
+	return apiGroupList, resourcesByGV, failedGVs, nil
 }
 
 // downloadAPIs returns the discovery groups and (if aggregated format) the
 // discovery resources. The returned groups will always exist, but the
-// resources map may be nil.
-func (d *DiscoveryClient) downloadAPIs() (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList, error) {
+// resources map may be nil. Returned "failedGVs" can be empty, but will
+// only be nil in the case of a returned error.
+func (d *DiscoveryClient) downloadAPIs() (
+	*metav1.APIGroupList,
+	map[schema.GroupVersion]*metav1.APIResourceList,
+	map[schema.GroupVersion]error,
+	error) {
 	accept := acceptDiscoveryFormats
 	if d.UseLegacyDiscovery {
 		accept = AcceptV1
@@ -283,42 +306,59 @@ func (d *DiscoveryClient) downloadAPIs() (*metav1.APIGroupList, map[schema.Group
 		Do(context.TODO()).
 		ContentType(&responseContentType).
 		Raw()
-	// Special error handling for 403 or 404 to be compatible with older v1.0 servers.
-	// Return empty group list to be merged with /api.
-	if err != nil && !errors.IsNotFound(err) && !errors.IsForbidden(err) {
-		return nil, nil, err
-	}
-	if err != nil && (errors.IsNotFound(err) || errors.IsForbidden(err)) {
-		return &metav1.APIGroupList{}, nil, nil
+	if err != nil {
+		return nil, nil, nil, err
 	}
 
 	apiGroupList := &metav1.APIGroupList{}
+	failedGVs := map[schema.GroupVersion]error{}
 	var resourcesByGV map[schema.GroupVersion]*metav1.APIResourceList
 	// Switch on content-type server responded with: aggregated or unaggregated.
-	switch responseContentType {
-	case AcceptV1:
-		err = json.Unmarshal(body, apiGroupList)
-		if err != nil {
-			return nil, nil, err
-		}
-	case AcceptV2Beta1:
+	switch {
+	case isV2Beta1ContentType(responseContentType):
 		var aggregatedDiscovery apidiscovery.APIGroupDiscoveryList
 		err = json.Unmarshal(body, &aggregatedDiscovery)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, nil, err
 		}
-		apiGroupList, resourcesByGV = SplitGroupsAndResources(aggregatedDiscovery)
+		apiGroupList, resourcesByGV, failedGVs = SplitGroupsAndResources(aggregatedDiscovery)
 	default:
-		return nil, nil, fmt.Errorf("Unknown discovery response content-type: %s", responseContentType)
+		// Default is unaggregated discovery v1.
+		err = json.Unmarshal(body, apiGroupList)
+		if err != nil {
+			return nil, nil, nil, err
+		}
 	}
 
-	return apiGroupList, resourcesByGV, nil
+	return apiGroupList, resourcesByGV, failedGVs, nil
+}
+
+// isV2Beta1ContentType checks of the content-type string is both
+// "application/json" and contains the v2beta1 content-type params.
+// NOTE: This function is resilient to the ordering of the
+// content-type parameters, as well as parameters added by
+// intermediaries such as proxies or gateways. Examples:
+//
+//	"application/json; g=apidiscovery.k8s.io;v=v2beta1;as=APIGroupDiscoveryList" = true
+//	"application/json; as=APIGroupDiscoveryList;v=v2beta1;g=apidiscovery.k8s.io" = true
+//	"application/json; as=APIGroupDiscoveryList;v=v2beta1;g=apidiscovery.k8s.io;charset=utf-8" = true
+//	"application/json" = false
+//	"application/json; charset=UTF-8" = false
+func isV2Beta1ContentType(contentType string) bool {
+	base, params, err := mime.ParseMediaType(contentType)
+	if err != nil {
+		return false
+	}
+	return runtime.ContentTypeJSON == base &&
+		params["g"] == "apidiscovery.k8s.io" &&
+		params["v"] == "v2beta1" &&
+		params["as"] == "APIGroupDiscoveryList"
 }
 
 // ServerGroups returns the supported groups, with information like supported versions and the
 // preferred version.
 func (d *DiscoveryClient) ServerGroups() (*metav1.APIGroupList, error) {
-	groups, _, err := d.GroupsAndMaybeResources()
+	groups, _, _, err := d.GroupsAndMaybeResources()
 	if err != nil {
 		return nil, err
 	}
@@ -341,8 +381,10 @@ func (d *DiscoveryClient) ServerResourcesForGroupVersion(groupVersion string) (r
 	}
 	err = d.restClient.Get().AbsPath(url.String()).Do(context.TODO()).Into(resources)
 	if err != nil {
-		// ignore 403 or 404 error to be compatible with an v1.0 server.
-		if groupVersion == "v1" && (errors.IsNotFound(err) || errors.IsForbidden(err)) {
+		// Tolerate core/v1 not found response by returning empty resource list;
+		// this probably should not happen. But we should verify all callers are
+		// not depending on this toleration before removal.
+		if groupVersion == "v1" && errors.IsNotFound(err) {
 			return resources, nil
 		}
 		return nil, err
@@ -383,13 +425,14 @@ func IsGroupDiscoveryFailedError(err error) bool {
 func ServerGroupsAndResources(d DiscoveryInterface) ([]*metav1.APIGroup, []*metav1.APIResourceList, error) {
 	var sgs *metav1.APIGroupList
 	var resources []*metav1.APIResourceList
+	var failedGVs map[schema.GroupVersion]error
 	var err error
 
 	// If the passed discovery object implements the wider AggregatedDiscoveryInterface,
 	// then attempt to retrieve aggregated discovery with both groups and the resources.
 	if ad, ok := d.(AggregatedDiscoveryInterface); ok {
 		var resourcesByGV map[schema.GroupVersion]*metav1.APIResourceList
-		sgs, resourcesByGV, err = ad.GroupsAndMaybeResources()
+		sgs, resourcesByGV, failedGVs, err = ad.GroupsAndMaybeResources()
 		for _, resourceList := range resourcesByGV {
 			resources = append(resources, resourceList)
 		}
@@ -404,8 +447,15 @@ func ServerGroupsAndResources(d DiscoveryInterface) ([]*metav1.APIGroup, []*meta
 	for i := range sgs.Groups {
 		resultGroups = append(resultGroups, &sgs.Groups[i])
 	}
+	// resources is non-nil if aggregated discovery succeeded.
 	if resources != nil {
-		return resultGroups, resources, nil
+		// Any stale Group/Versions returned by aggregated discovery
+		// must be surfaced to the caller as failed Group/Versions.
+		var ferr error
+		if len(failedGVs) > 0 {
+			ferr = &ErrGroupDiscoveryFailed{Groups: failedGVs}
+		}
+		return resultGroups, resources, ferr
 	}
 
 	groupVersionResources, failedGroups := fetchGroupVersionResources(d, sgs)
@@ -436,16 +486,18 @@ func ServerPreferredResources(d DiscoveryInterface) ([]*metav1.APIResourceList,
 	var err error
 
 	// If the passed discovery object implements the wider AggregatedDiscoveryInterface,
-	// then it is attempt to retrieve both the groups and the resources.
+	// then it is attempt to retrieve both the groups and the resources. "failedGroups"
+	// are Group/Versions returned as stale in AggregatedDiscovery format.
 	ad, ok := d.(AggregatedDiscoveryInterface)
 	if ok {
-		serverGroupList, groupVersionResources, err = ad.GroupsAndMaybeResources()
+		serverGroupList, groupVersionResources, failedGroups, err = ad.GroupsAndMaybeResources()
 	} else {
 		serverGroupList, err = d.ServerGroups()
 	}
 	if err != nil {
 		return nil, err
 	}
+	// Non-aggregated discovery must fetch resources from Groups.
 	if groupVersionResources == nil {
 		groupVersionResources, failedGroups = fetchGroupVersionResources(d, serverGroupList)
 	}