Add MergeMode for toggling highlighting of merge conflicts

docs/api-reference/landscapekit-v1alpha1.md

@@ -81,6 +81,23 @@ _Appears in:_
 
 
 
+#### MergeMode
+
+_Underlying type:_ _string_
+
+MergeMode controls how operator overwrites are handled during three-way merge.
+
+
+
+_Appears in:_
+- [LandscapeKitConfiguration](#landscapekitconfiguration)
+
+| Field | Description |
+| --- | --- |
+| `Informative` | MergeModeInformative annotates operator-overwritten values with a comment showing the current GLK default.<br /> |
+| `Silent` | MergeModeSilent retains operator overwrites without annotation.<br /> |
+
+
 #### OCMComponent
 
 

example/20-componentconfig-glk.yaml

@@ -19,3 +19,4 @@ kind: LandscapeKitConfiguration
 #   - component-name
 # versionConfig:
 #   defaultVersionsUpdateStrategy: ReleaseBranch
+# mergeMode: Informative

hack/tools/prettify/main.go

@@ -11,6 +11,7 @@ import (
 
 	flag "github.com/spf13/pflag"
 
+	configv1alpha1 "github.com/gardener/gardener-landscape-kit/pkg/apis/config/v1alpha1"
 	"github.com/gardener/gardener-landscape-kit/pkg/utils/meta"
 )
 
@@ -31,7 +32,7 @@ func main() {
 	if err != nil {
 		log.Fatalf("Error reading file: %s", err)
 	}
-	prettified, err := meta.ThreeWayMergeManifest(nil, content, nil)
+	prettified, err := meta.ThreeWayMergeManifest(nil, content, nil, configv1alpha1.MergeModeSilent)
 	if err != nil {
 		log.Fatalf("Marshalling failed: %s", err)
 	}

pkg/apis/config/v1alpha1/defaults.go

@@ -3,3 +3,17 @@
 // SPDX-License-Identifier: Apache-2.0
 
 package v1alpha1
+
+// SetDefaults_LandscapeKitConfiguration sets default values for LandscapeKitConfiguration fields.
+func SetDefaults_LandscapeKitConfiguration(obj *LandscapeKitConfiguration) {
+	if obj.VersionConfig == nil {
+		obj.VersionConfig = &VersionConfiguration{}
+	}
+	if obj.VersionConfig.DefaultVersionsUpdateStrategy == nil {
+		obj.VersionConfig.DefaultVersionsUpdateStrategy = new(DefaultVersionsUpdateStrategyDisabled)
+	}
+
+	if obj.MergeMode == nil {
+		obj.MergeMode = new(MergeModeInformative)
+	}
+}

pkg/apis/config/v1alpha1/types.go

@@ -26,6 +26,11 @@ type LandscapeKitConfiguration struct {
 	// VersionConfig is the configuration for versioning.
 	// +optional
 	VersionConfig *VersionConfiguration `json:"versionConfig,omitempty"`
+	// MergeMode determines how merge conflicts are resolved:
+	// - "Informative" (default): New default values from GLK are added as comments after any customized values.
+	// - "Silent": Operator-customized values are retained, new default values are omitted.
+	// +optional
+	MergeMode *MergeMode `json:"mergeMode,omitempty"`
 }
 
 // ComponentsConfiguration contains configuration for components.
@@ -119,3 +124,19 @@ type VersionConfiguration struct {
 	// +optional
 	DefaultVersionsUpdateStrategy *DefaultVersionsUpdateStrategy `json:"defaultVersionsUpdateStrategy,omitempty"`
 }
+
+// MergeMode controls how operator overwrites are handled during three-way merge.
+type MergeMode string
+
+const (
+	// MergeModeInformative annotates operator-overwritten values with a comment showing the current GLK default.
+	MergeModeInformative MergeMode = "Informative"
+	// MergeModeSilent retains operator overwrites without annotation.
+	MergeModeSilent MergeMode = "Silent"
+)
+
+// AllowedMergeModes lists all allowed merge modes.
+var AllowedMergeModes = []string{
+	string(MergeModeInformative),
+	string(MergeModeSilent),
+}

pkg/apis/config/v1alpha1/validation/validation.go

@@ -36,6 +36,10 @@ func ValidateLandscapeKitConfiguration(conf *configv1alpha1.LandscapeKitConfigur
 		allErrs = append(allErrs, ValidateVersionConfig(conf.VersionConfig, field.NewPath("versionConfig"))...)
 	}
 
+	if conf.MergeMode != nil && !slices.Contains(configv1alpha1.AllowedMergeModes, string(*conf.MergeMode)) {
+		allErrs = append(allErrs, field.NotSupported(field.NewPath("mergeMode"), *conf.MergeMode, configv1alpha1.AllowedMergeModes))
+	}
+
 	return allErrs
 }
 

pkg/apis/config/v1alpha1/validation/validation_test.go

@@ -294,6 +294,43 @@ var _ = Describe("Validation", func() {
 				Expect(errList).To(BeEmpty())
 			})
 		})
+
+		Context("MergeMode Configuration", func() {
+			It("should pass with valid MergeMode values", func() {
+				for _, mode := range []v1alpha1.MergeMode{
+					v1alpha1.MergeModeInformative,
+					v1alpha1.MergeModeSilent,
+				} {
+					conf := &v1alpha1.LandscapeKitConfiguration{
+						MergeMode: &mode,
+					}
+					errList := validation.ValidateLandscapeKitConfiguration(conf)
+					Expect(errList).To(BeEmpty(), fmt.Sprintf("MergeMode %q should be valid", mode))
+				}
+			})
+
+			It("should pass when MergeMode is not set", func() {
+				conf := &v1alpha1.LandscapeKitConfiguration{}
+				errList := validation.ValidateLandscapeKitConfiguration(conf)
+				Expect(errList).To(BeEmpty())
+			})
+
+			It("should fail with an invalid MergeMode value", func() {
+				invalid := v1alpha1.MergeMode("Invalid")
+				conf := &v1alpha1.LandscapeKitConfiguration{
+					MergeMode: &invalid,
+				}
+
+				errList := validation.ValidateLandscapeKitConfiguration(conf)
+				Expect(errList).To(ConsistOf(
+					PointTo(MatchFields(IgnoreExtras, Fields{
+						"Type":     Equal(field.ErrorTypeNotSupported),
+						"Field":    Equal("mergeMode"),
+						"BadValue": Equal(invalid),
+					})),
+				))
+			})
+		})
 	})
 })
 

pkg/cmd/resolve/plain/plain.go

@@ -6,10 +6,8 @@ package plain
 
 import (
 	"context"
-	"errors"
 	"fmt"
-	"os"
-	"path"
+	"strings"
 
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
@@ -22,6 +20,7 @@ import (
 	configv1alpha1 "github.com/gardener/gardener-landscape-kit/pkg/apis/config/v1alpha1"
 	"github.com/gardener/gardener-landscape-kit/pkg/cmd"
 	utilscomponentvector "github.com/gardener/gardener-landscape-kit/pkg/utils/componentvector"
+	utilsfiles "github.com/gardener/gardener-landscape-kit/pkg/utils/files"
 )
 
 var configDecoder runtime.Decoder
@@ -111,7 +110,7 @@ func (o *Options) loadConfigFile(filename string) error {
 
 func run(_ context.Context, opts *Options) error {
 	if opts.Config != nil && opts.Config.VersionConfig != nil {
-		if updateStrategy := opts.Config.VersionConfig.DefaultVersionsUpdateStrategy; updateStrategy != nil && *updateStrategy == configv1alpha1.DefaultVersionsUpdateStrategyReleaseBranch {
+		if *opts.Config.VersionConfig.DefaultVersionsUpdateStrategy == configv1alpha1.DefaultVersionsUpdateStrategyReleaseBranch {
 			opts.Log.Info("Updating default component vector file from the release branch", "branch", utilscomponentvector.GetReleaseBranchName())
 			var err error
 			// The componentvector.DefaultComponentsYAML is intentionally overridden, so that subsequently it can be used to extract the updated default component vector versions.
@@ -122,21 +121,30 @@ func run(_ context.Context, opts *Options) error {
 		}
 	}
 
-	compVectorFile := path.Join(opts.TargetDirPath, utilscomponentvector.ComponentVectorFilename)
-	opts.Log.Info("Writing component vector file", "file", compVectorFile)
-
-	var customBytes []byte
-	var err error
-	if customBytes, err = opts.fs.ReadFile(compVectorFile); err != nil {
-		if !errors.Is(err, os.ErrNotExist) {
-			return fmt.Errorf("failed to read component vector override file: %w", err)
-		}
+	var (
+		err             error
+		newDefaultCV    utilscomponentvector.Interface
+		newDefaultBytes []byte
+	)
+	newDefaultCV, err = utilscomponentvector.NewWithOverride(componentvector.DefaultComponentsYAML)
+	if err != nil {
+		return fmt.Errorf("failed to build default component vector: %w", err)
 	}
-
-	componentVector, err := utilscomponentvector.NewWithOverride(componentvector.DefaultComponentsYAML, customBytes)
+	newDefaultBytes, err = utilscomponentvector.NameVersionBytes(newDefaultCV)
 	if err != nil {
-		return fmt.Errorf("failed to create component vector: %w", err)
+		return fmt.Errorf("failed to marshal default component vector: %w", err)
 	}
 
-	return utilscomponentvector.WriteComponentVectorFile(opts.fs, opts.TargetDirPath, componentVector)
+	header := []byte(strings.Join([]string{
+		"# This file is updated by the gardener-landscape-kit.",
+		"# If this file is present in the root of a gardener-landscape-kit-managed repository, the component versions will be used as overrides.",
+		"# If custom component versions should be used, it is recommended to modify the specified versions here and run the `generate` command afterwards.",
+	}, "\n") + "\n")
+	newDefaultBytes = append(header, newDefaultBytes...)
+
+	if err := utilsfiles.WriteObjectsToFilesystem(map[string][]byte{utilscomponentvector.ComponentVectorFilename: newDefaultBytes}, opts.TargetDirPath, "", opts.fs, *opts.Config.MergeMode); err != nil {
+		return fmt.Errorf("failed to write updated component vector: %w", err)
+	}
+
+	return nil
 }

pkg/components/flux/component.go

@@ -94,7 +94,7 @@ func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
 	delete(objects, "flux-system/gitignore")
 	delete(objects, "flux-system/doc.go")
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), DirName, opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), DirName, opts.GetFilesystem(), opts.GetMergeMode())
 }
 
 func writeGitignoreFile(options components.LandscapeOptions) error {

pkg/components/flux/component_test.go

@@ -54,21 +54,24 @@ var _ = Describe("Flux Component Generation", func() {
 
 		fs = afero.Afero{Fs: afero.NewMemMapFs()}
 
+		config := &v1alpha1.LandscapeKitConfiguration{
+			Git: &v1alpha1.GitRepository{
+				URL: repoURL,
+				Paths: v1alpha1.PathConfiguration{
+					Landscape: relativeLandscapePath,
+				},
+			},
+		}
+		v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(config)
+
 		var err error
 		opts, err = components.NewLandscapeOptions(
 			&generateoptions.Options{
 				Options: &cmd.Options{
 					Log: logr.Discard(),
 				},
 				TargetDirPath: targetPath,
-				Config: &v1alpha1.LandscapeKitConfiguration{
-					Git: &v1alpha1.GitRepository{
-						URL: repoURL,
-						Paths: v1alpha1.PathConfiguration{
-							Landscape: relativeLandscapePath,
-						},
-					},
-				},
+				Config:        config,
 			},
 			fs,
 		)

pkg/components/gardener-extensions/networking-calico/component.go

@@ -78,7 +78,7 @@ func writeBaseTemplateFiles(opts components.Options) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }
 
 func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
@@ -100,5 +100,5 @@ func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }

pkg/components/gardener-extensions/networking-calico/component_test.go

@@ -35,7 +35,9 @@ var _ = Describe("Component Generation", func() {
 		generateOpts = &generateoptions.Options{
 			TargetDirPath: "/repo/baseDir",
 			Options:       cmdOpts,
+			Config:        &v1alpha1.LandscapeKitConfiguration{},
 		}
+		v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 	})
 
 	Describe("#GenerateBase", func() {
@@ -68,6 +70,7 @@ var _ = Describe("Component Generation", func() {
 			generateOpts.Config = &v1alpha1.LandscapeKitConfiguration{
 				Git: &v1alpha1.GitRepository{Paths: v1alpha1.PathConfiguration{Landscape: "./landscapeDir", Base: "./baseDir"}},
 			}
+			v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 		})
 
 		It("should generate only the flux kustomization into the landscape dir", func() {

pkg/components/gardener-extensions/networking-cilium/component.go

@@ -78,7 +78,7 @@ func writeBaseTemplateFiles(opts components.Options) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }
 
 func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
@@ -100,5 +100,5 @@ func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }

pkg/components/gardener-extensions/networking-cilium/component_test.go

@@ -35,7 +35,9 @@ var _ = Describe("Component Generation", func() {
 		generateOpts = &generateoptions.Options{
 			TargetDirPath: "/repo/baseDir",
 			Options:       cmdOpts,
+			Config:        &v1alpha1.LandscapeKitConfiguration{},
 		}
+		v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 	})
 
 	Describe("#GenerateBase", func() {
@@ -68,6 +70,7 @@ var _ = Describe("Component Generation", func() {
 			generateOpts.Config = &v1alpha1.LandscapeKitConfiguration{
 				Git: &v1alpha1.GitRepository{Paths: v1alpha1.PathConfiguration{Landscape: "./landscapeDir", Base: "./baseDir"}},
 			}
+			v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 		})
 
 		It("should generate only the flux kustomization into the landscape dir", func() {

pkg/components/gardener-extensions/os-gardenlinux/component.go

@@ -78,7 +78,7 @@ func writeBaseTemplateFiles(opts components.Options) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }
 
 func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
@@ -100,5 +100,5 @@ func writeLandscapeTemplateFiles(opts components.LandscapeOptions) error {
 		return err
 	}
 
-	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem())
+	return files.WriteObjectsToFilesystem(objects, opts.GetTargetPath(), path.Join(components.DirName, ComponentDirectory), opts.GetFilesystem(), opts.GetMergeMode())
 }

pkg/components/gardener-extensions/os-gardenlinux/component_test.go

@@ -35,7 +35,9 @@ var _ = Describe("Component Generation", func() {
 		generateOpts = &generateoptions.Options{
 			TargetDirPath: "/repo/baseDir",
 			Options:       cmdOpts,
+			Config:        &v1alpha1.LandscapeKitConfiguration{},
 		}
+		v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 	})
 
 	Describe("#GenerateBase", func() {
@@ -68,6 +70,7 @@ var _ = Describe("Component Generation", func() {
 			generateOpts.Config = &v1alpha1.LandscapeKitConfiguration{
 				Git: &v1alpha1.GitRepository{Paths: v1alpha1.PathConfiguration{Landscape: "./landscapeDir", Base: "./baseDir"}},
 			}
+			v1alpha1.SetObjectDefaults_LandscapeKitConfiguration(generateOpts.Config)
 		})
 
 		It("should generate only the flux kustomization into the landscape dir", func() {