Add feature flag for GEP-33 Capabilities support (#30)

* GEP-33 feature flag

* fix lint

* fix coderabbit

* fix copilot

* fix copilot v2

Author: anton-paulovich

.golangci.yaml

@@ -135,7 +135,7 @@ linters:
         # for github.com/sapcc/keppel et al
         - github.com/go-gorp/gorp/v3
       toolchain-forbidden: true
-      go-version-pattern: 1\.\d+(\.0)?$
+      go-version-pattern: 1\.\d+(\.\d+)?$
     gosec:
       excludes:
         # gosec wants us to set a short ReadHeaderTimeout to avoid Slowloris attacks, but doing so would expose us to Keep-Alive race conditions (see https://iximiuz.com/en/posts/reverse-proxy-http-keep-alive-and-502s/

cloudprofilesync/imageupdater.go

@@ -17,13 +17,14 @@ import (
 func filterImages(log logr.Logger, versions []SourceImage) []SourceImage {
 	filtered := make([]SourceImage, 0, len(versions))
 	for _, version := range versions {
-		_, err := semver.Parse(version.Version)
+		versionStr := version.effectiveVersion()
+		_, err := semver.Parse(versionStr)
 		if err != nil {
-			log.V(1).Info("skipping invalid version", "version", version.Version)
+			log.V(1).Info("skipping invalid version", "version", versionStr)
 			continue
 		}
 		if len(version.Architectures) == 0 {
-			log.V(1).Info("skipping version with no architectures", "version", version.Version)
+			log.V(1).Info("skipping version with no architectures", "version", versionStr)
 			continue
 		}
 		filtered = append(filtered, version)
@@ -32,10 +33,11 @@ func filterImages(log logr.Logger, versions []SourceImage) []SourceImage {
 }
 
 type ImageUpdater struct {
-	Log       logr.Logger
-	Source    Source
-	Provider  Provider
-	ImageName string
+	Log                logr.Logger
+	Source             Source
+	Provider           Provider
+	ImageName          string
+	EnableCapabilities bool
 }
 
 func (iu *ImageUpdater) Update(ctx context.Context, cpSpec *gardenerv1beta1.CloudProfileSpec) error {
@@ -48,6 +50,9 @@ func (iu *ImageUpdater) Update(ctx context.Context, cpSpec *gardenerv1beta1.Clou
 	// in the source images may lead to a changed order in the CloudProfile,
 	// causing unnecesscary reconciliations.
 	slices.SortFunc(sourceImages, func(a, b SourceImage) int {
+		if c := cmp.Compare(a.effectiveVersion(), b.effectiveVersion()); c != 0 {
+			return c
+		}
 		return cmp.Compare(a.Version, b.Version)
 	})
 	imageIndex := slices.IndexFunc(cpSpec.MachineImages, func(img gardenerv1beta1.MachineImage) bool {
@@ -62,7 +67,9 @@ func (iu *ImageUpdater) Update(ctx context.Context, cpSpec *gardenerv1beta1.Clou
 	for idx, version := range image.Versions {
 		existingVersions[version.Version] = idx
 	}
+
 	for _, sourceImage := range sourceImages {
+		// Always write the full tag version (legacy path, safe for running Shoots).
 		if idx, exists := existingVersions[sourceImage.Version]; exists {
 			image.Versions[idx].Architectures = sourceImage.Architectures
 		} else {
@@ -72,8 +79,30 @@ func (iu *ImageUpdater) Update(ctx context.Context, cpSpec *gardenerv1beta1.Clou
 				},
 				Architectures: sourceImage.Architectures,
 			})
+			existingVersions[sourceImage.Version] = len(image.Versions) - 1
+		}
+
+		// When capabilities are enabled, also write the clean version entry.
+		if iu.EnableCapabilities && sourceImage.CleanVersion != "" && sourceImage.CleanVersion != sourceImage.Version {
+			if idx, exists := existingVersions[sourceImage.CleanVersion]; exists {
+				existing := &image.Versions[idx]
+				for _, arch := range sourceImage.Architectures {
+					if !slices.Contains(existing.Architectures, arch) {
+						existing.Architectures = append(existing.Architectures, arch)
+					}
+				}
+			} else {
+				image.Versions = append(image.Versions, gardenerv1beta1.MachineImageVersion{
+					ExpirableVersion: gardenerv1beta1.ExpirableVersion{
+						Version: sourceImage.CleanVersion,
+					},
+					Architectures: slices.Clone(sourceImage.Architectures),
+				})
+				existingVersions[sourceImage.CleanVersion] = len(image.Versions) - 1
+			}
 		}
 	}
+
 	if iu.Provider != nil {
 		if err := iu.Provider.Configure(cpSpec, sourceImages); err != nil {
 			return fmt.Errorf("failed to invoke provider: %w", err)