feat: Refactors featuregate lifecycle management script

- rename featuregate_linter to compatibility_lifecycle
- add feature removal verify to follow N+3 rule
- remove unversioned related operation
- rename yaml folder name to "reference"

hack/update-featuregates.sh

@@ -14,8 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# This script updates  test/featuregates_linter/test_data/unversioned_feature_list.yaml and
+# This script updates test/compatibility_lifecycle/reference/versioned_feature_list.yaml 
-# test/featuregates_linter/test_data/versioned_feature_list.yaml with all the feature gate features.
+# with all the feature gate features.
 # Usage: `hack/update-featuregates.sh`.
 
 set -o errexit
@@ -27,4 +27,4 @@ source "${KUBE_ROOT}/hack/lib/init.sh"
 
 cd "${KUBE_ROOT}"
 
-go run test/featuregates_linter/main.go feature-gates update
+go run test/compatibility_lifecycle/main.go feature-gates update

hack/verify-featuregates.sh

@@ -14,8 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# This script checks test/featuregates_linter/test_data/unversioned_feature_list.yaml and
+# This script checks test/compatibility_lifecycle/reference/versioned_feature_list.yaml
-# test/featuregates_linter/test_data/versioned_feature_list.yaml are up to date with all the feature gate features.
+# are up to date with all the feature gate features, and verifies no feature is removed before 3 versions post `lockedToDefault:true`.
 # We should run `hack/update-featuregates.sh` if the list is out of date.
 # Usage: `hack/verify-featuregates.sh`.
 
@@ -30,7 +30,7 @@ kube::golang::setup_env
 
 cd "${KUBE_ROOT}"
 
-if ! go run test/featuregates_linter/main.go feature-gates verify; then
+if ! go run test/compatibility_lifecycle/main.go feature-gates verify; then
   echo "Please run 'hack/update-featuregates.sh' to update the feature list."
   exit 1
 fi

test/compatibility_lifecycle/README.md

@@ -0,0 +1,10 @@
+This directory contains commands for [compatibility lifecycle verification](https://github.com/kubernetes/enhancements/blob/master/keps/sig-architecture/4330-compatibility-versions/README.md)
+
+Currently, the following commands are implemented:
+```
+# Verify feature gate list is up to date
+go run test/compatibility_lifecycle/main.go feature-gates verify
+
+# Update feature gate list
+go run test/compatibility_lifecycle/main.go feature-gates update
+```

test/compatibility_lifecycle/cmd/feature_gates.go

@@ -31,18 +31,25 @@ import (
 	"github.com/spf13/cobra"
 
 	"k8s.io/apimachinery/pkg/util/version"
+	baseversion "k8s.io/component-base/version"
 	yaml "sigs.k8s.io/yaml/goyaml.v2"
 )
 
 var (
 	alphabeticalOrder        bool
 	k8RootPath               string
-	unversionedFeatureListFile = "test/featuregates_linter/test_data/unversioned_feature_list.yaml"
+	versionedFeatureListFile = "test/compatibility_lifecycle/reference/versioned_feature_list.yaml"
-	versionedFeatureListFile   = "test/featuregates_linter/test_data/versioned_feature_list.yaml"
+	// thresholdVersion is the version after which we require emulation support for feature removal
+	// 1.31 is when we introduced emulation version support
+	thresholdVersion = version.MajorMinor(1, 31)
 )
 
 const (
 	featureGatePkg       = "\"k8s.io/component-base/featuregate\""
+	generatedFileWarning = `# This file is generated by compatibility_lifecycle tool.
+# Do not edit manually. Run hack/update-featuregates.sh to regenerate.
+
+`
 )
 
 type featureSpec struct {
@@ -95,39 +102,33 @@ func NewUpdateFeatureListCommand() *cobra.Command {
 }
 
 func verifyFeatureListFunc(cmd *cobra.Command, args []string) {
-	if err := verifyOrUpdateFeatureList(k8RootPath, unversionedFeatureListFile, false, false); err != nil {
+	currentVersion := version.MustParse(baseversion.DefaultKubeBinaryVersion)
-		fmt.Fprintf(os.Stderr, "Failed to verify feature list: \n%s", err)
+	if err := verifyOrUpdateFeatureList(k8RootPath, versionedFeatureListFile, currentVersion, false); err != nil {
-		os.Exit(1)
-	}
-	if err := verifyOrUpdateFeatureList(k8RootPath, versionedFeatureListFile, false, true); err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to verify versioned feature list: \n%s", err)
 		os.Exit(1)
 	}
 }
 
 func updateFeatureListFunc(cmd *cobra.Command, args []string) {
-	if err := verifyOrUpdateFeatureList(k8RootPath, unversionedFeatureListFile, true, false); err != nil {
+	currentVersion := version.MustParse(baseversion.DefaultKubeBinaryVersion)
-		fmt.Fprintf(os.Stderr, "Failed to update feature list: \n%s", err)
+	if err := verifyOrUpdateFeatureList(k8RootPath, versionedFeatureListFile, currentVersion, true); err != nil {
-		os.Exit(1)
-	}
-	if err := verifyOrUpdateFeatureList(k8RootPath, versionedFeatureListFile, true, true); err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to update versioned feature list: \n%s", err)
 		os.Exit(1)
 	}
 }
 
 // verifyOrUpdateFeatureList walks all the files under pkg/ and staging/ to find the list of all the features in
-// map[featuregate.Feature]featuregate.FeatureSpec or map[featuregate.Feature]featuregate.VersionedSpecs.
+// map[featuregate.Feature]featuregate.VersionedSpecs.
 // It will then update the feature list in featureListFile, or verifies there is no change from the existing list.
-func verifyOrUpdateFeatureList(rootPath, featureListFile string, update, versioned bool) error {
+func verifyOrUpdateFeatureList(rootPath, featureListFile string, currentVersion *version.Version, update bool) error {
 	featureList := []featureInfo{}
-	features, err := searchPathForFeatures(filepath.Join(rootPath, "pkg"), versioned)
+	features, err := searchPathForFeatures(filepath.Join(rootPath, "pkg"))
 	if err != nil {
 		return err
 	}
 	featureList = append(featureList, features...)
 
-	features, err = searchPathForFeatures(filepath.Join(rootPath, "staging"), versioned)
+	features, err = searchPathForFeatures(filepath.Join(rootPath, "staging"))
 	if err != nil {
 		return err
 	}
@@ -153,29 +154,22 @@ func verifyOrUpdateFeatureList(rootPath, featureListFile string, update, version
 		return err
 	}
 
-	// only feature deletion is allowed for unversioned features.
+	if err := verifyFeatureRemoval(featureList, baseFeatureList, currentVersion, thresholdVersion); err != nil {
-	// all new features or feature updates should be migrated to versioned feature gate.
-	// https://github.com/kubernetes/kubernetes/issues/125031
-	if !versioned {
-		if err := verifyFeatureDeletionOnly(featureList, baseFeatureList); err != nil {
 		return err
 	}
-	}
 
 	featureListBytes, err := yaml.Marshal(featureList)
 	if err != nil {
 		return err
 	}
+	featureListBytes = []byte(generatedFileWarning + string(featureListBytes))
 	if update {
 		return os.WriteFile(filePath, featureListBytes, 0644)
 	}
 
 	if diff := cmp.Diff(featureListBytes, baseFeatureListBytes); diff != "" {
-		if versioned {
 		return fmt.Errorf("detected diff in versioned feature list (%s), diff: \n%s", versionedFeatureListFile, diff)
-		} else {
+
-			return fmt.Errorf("detected diff in unversioned feature list (%s), diff: \n%s", unversionedFeatureListFile, diff)
-		}
 	}
 	return nil
 }
@@ -205,27 +199,70 @@ func dedupeFeatureList(featureList []featureInfo) ([]featureInfo, error) {
 	return deduped, nil
 }
 
-func verifyFeatureDeletionOnly(newFeatureList []featureInfo, oldFeatureList []featureInfo) error {
+// verifyFeatureRemoval checks if removed features are allowed to be removed based on their lifecycle.
-	oldFeatureSet := make(map[string]*featureInfo)
+// Alpha features can be removed anytime without error.
-	for _, f := range oldFeatureList {
+// Returns error if:
-		oldFeatureSet[f.Name] = &f
+//   - Beta features are removed (not allowed)
+//   - GA/Deprecated features are removed without being locked to default
+//   - GA/Deprecated features locked after v1.31 are removed before 3 minor versions
+//     have passed (required for emulation support)
+func verifyFeatureRemoval(featureList []featureInfo, baseFeatureList []featureInfo,
+	currentVersion *version.Version, thresholdVersion *version.Version) error {
+	if thresholdVersion == nil {
+		thresholdVersion = version.MajorMinor(0, 0)
 	}
-	newFeatures := []string{}
+	baseFeatures := make(map[string]featureInfo)
-	for _, f := range newFeatureList {
+	for _, f := range baseFeatureList {
-		oldSpecs, found := oldFeatureSet[f.Name]
+		baseFeatures[f.Name] = f
-		if !found {
-			newFeatures = append(newFeatures, f.Name)
-		} else if !reflect.DeepEqual(*oldSpecs, f) {
-			return fmt.Errorf("feature %s changed with diff: %s", f.Name, cmp.Diff(*oldSpecs, f))
 	}
+	currentFeatures := make(map[string]featureInfo)
+	for _, f := range featureList {
+		currentFeatures[f.Name] = f
+	}
+
+	for name, baseFeature := range baseFeatures {
+		// Check if feature was removed
+		if _, found := currentFeatures[name]; found {
+			continue
+		}
+
+		// Feature was removed, check if allowed
+		specs := baseFeature.VersionedSpecs
+		if len(specs) == 0 {
+			return fmt.Errorf("feature %s has no version specs", name)
+		}
+
+		lastSpec := specs[len(specs)-1]
+		switch lastSpec.PreRelease {
+		case "Alpha":
+			continue // can remove alpha features anytime
+		case "Beta":
+			return fmt.Errorf("feature %s cannot be removed while in beta", name)
+		case "GA", "Deprecated":
+			if !lastSpec.LockToDefault {
+				return fmt.Errorf("feature %s cannot be removed because it is in GA or Deprecated state and is not locked to default", name)
+			}
+			specVer, err := version.Parse(lastSpec.Version)
+			if err != nil {
+				return fmt.Errorf("invalid version \"%s\" for feature %s: %w", lastSpec.Version, name, err)
+			}
+			// we do not require the 3 version retention for features locked before the thresholdVersion.
+			// TODO: remove after 1.34
+			if !specVer.GreaterThan(thresholdVersion) {
+				continue
+			}
+			minRemovalVer := specVer.AddMinor(3)
+			if currentVersion.LessThan(minRemovalVer) {
+				return fmt.Errorf("feature %s cannot be removed until version %s (required for emulation support)",
+					name, minRemovalVer)
+			}
+
 		}
-	if len(newFeatures) > 0 {
-		return fmt.Errorf("new features added to FeatureSpec map! %v\nPlease add new features through VersionedSpecs map ONLY! ", newFeatures)
 	}
 	return nil
 }
 
-func searchPathForFeatures(path string, versioned bool) ([]featureInfo, error) {
+func searchPathForFeatures(path string) ([]featureInfo, error) {
 	allFeatures := []featureInfo{}
 	// Create a FileSet to work with
 	fset := token.NewFileSet()
@@ -239,7 +276,12 @@ func searchPathForFeatures(path string, versioned bool) ([]featureInfo, error) {
 		if strings.HasSuffix(path, "_test.go") {
 			return nil
 		}
-		features, parseErr := extractFeatureInfoListFromFile(fset, path, versioned)
+		// exclude generated files
+		base := filepath.Base(path)
+		if strings.HasPrefix(base, "zz_generated") {
+			return nil
+		}
+		features, parseErr := extractFeatureInfoListFromFile(fset, path)
 		if parseErr != nil {
 			return parseErr
 		}
@@ -249,9 +291,9 @@ func searchPathForFeatures(path string, versioned bool) ([]featureInfo, error) {
 	return allFeatures, err
 }
 
-// extractFeatureInfoListFromFile extracts info all the the features from
+// extractFeatureInfoListFromFile extracts info of all the features from
-// map[featuregate.Feature]featuregate.FeatureSpec or map[featuregate.Feature]featuregate.VersionedSpecs from the given file.
+// map[featuregate.Feature]featuregate.VersionedSpecs in the given file.
-func extractFeatureInfoListFromFile(fset *token.FileSet, filePath string, versioned bool) (allFeatures []featureInfo, err error) {
+func extractFeatureInfoListFromFile(fset *token.FileSet, filePath string) (allFeatures []featureInfo, err error) {
 	// Parse the file and create an AST
 	absFilePath, err := filepath.Abs(filePath)
 	if err != nil {
@@ -274,7 +316,7 @@ func extractFeatureInfoListFromFile(fset *token.FileSet, filePath string, versio
 				if vspec, ok := spec.(*ast.ValueSpec); ok {
 					for _, name := range vspec.Names {
 						for _, value := range vspec.Values {
-							features, err := extractFeatureInfoList(filePath, value, aliasMap, variables, versioned)
+							features, err := extractFeatureInfoList(filePath, value, aliasMap, variables)
 							if err != nil {
 								return allFeatures, err
 							}
@@ -291,7 +333,7 @@ func extractFeatureInfoListFromFile(fset *token.FileSet, filePath string, versio
 			for _, stmt := range fd.Body.List {
 				if st, ok := stmt.(*ast.ReturnStmt); ok {
 					for _, value := range st.Results {
-						features, err := extractFeatureInfoList(filePath, value, aliasMap, variables, versioned)
+						features, err := extractFeatureInfoList(filePath, value, aliasMap, variables)
 						if err != nil {
 							return allFeatures, err
 						}
@@ -332,8 +374,8 @@ func verifyAlphabeticOrder(keys []string, path string) error {
 }
 
 // extractFeatureInfoList extracts the info all the the features from
-// map[featuregate.Feature]featuregate.FeatureSpec or map[featuregate.Feature]featuregate.VersionedSpecs.
+// map[featuregate.Feature]featuregate.VersionedSpecs.
-func extractFeatureInfoList(filePath string, v ast.Expr, aliasMap map[string]string, variables map[string]ast.Expr, versioned bool) ([]featureInfo, error) {
+func extractFeatureInfoList(filePath string, v ast.Expr, aliasMap map[string]string, variables map[string]ast.Expr) ([]featureInfo, error) {
 	keys := []string{}
 	features := []featureInfo{}
 	cl, ok := v.(*ast.CompositeLit)
@@ -344,7 +386,7 @@ func extractFeatureInfoList(filePath string, v ast.Expr, aliasMap map[string]str
 	if !ok {
 		return features, nil
 	}
-	if !isFeatureSpecType(mt.Value, aliasMap, versioned) {
+	if !isFeatureSpecType(mt.Value, aliasMap) {
 		return features, nil
 	}
 	for _, elt := range cl.Elts {
@@ -352,7 +394,7 @@ func extractFeatureInfoList(filePath string, v ast.Expr, aliasMap map[string]str
 		if !ok {
 			continue
 		}
-		info, err := parseFeatureInfo(variables, kv, versioned)
+		info, err := parseFeatureInfo(variables, kv)
 		if err != nil {
 			return features, err
 		}
@@ -368,11 +410,8 @@ func extractFeatureInfoList(filePath string, v ast.Expr, aliasMap map[string]str
 	return features, nil
 }
 
-func isFeatureSpecType(v ast.Expr, aliasMap map[string]string, versioned bool) bool {
+func isFeatureSpecType(v ast.Expr, aliasMap map[string]string) bool {
-	typeName := "FeatureSpec"
+	typeName := "VersionedSpecs"
-	if versioned {
-		typeName = "VersionedSpecs"
-	}
 	alias, ok := aliasMap[featureGatePkg]
 	if ok {
 		typeName = alias + "." + typeName
@@ -380,20 +419,16 @@ func isFeatureSpecType(v ast.Expr, aliasMap map[string]string, versioned bool) b
 	return identifierName(v, false) == typeName
 }
 
-func parseFeatureInfo(variables map[string]ast.Expr, kv *ast.KeyValueExpr, versioned bool) (featureInfo, error) {
+func parseFeatureInfo(variables map[string]ast.Expr, kv *ast.KeyValueExpr) (featureInfo, error) {
 	info := featureInfo{
 		Name:           identifierName(kv.Key, true),
 		FullName:       identifierName(kv.Key, false),
 		VersionedSpecs: []featureSpec{},
 	}
 	specExps := []ast.Expr{}
-	if versioned {
 	if cl, ok := kv.Value.(*ast.CompositeLit); ok {
 		specExps = append(specExps, cl.Elts...)
 	}
-	} else {
-		specExps = append(specExps, kv.Value)
-	}
 	for _, specExp := range specExps {
 		spec, err := parseFeatureSpec(variables, specExp)
 		if err != nil {

test/compatibility_lifecycle/cmd/feature_gates_test.go

@@ -17,18 +17,26 @@ limitations under the License.
 package cmd
 
 import (
-	"fmt"
 	"go/ast"
 	"go/token"
 	"log"
 	"os"
 	"path/filepath"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"k8s.io/apimachinery/pkg/util/version"
 )
 
+const expectedHeader = `# This file is generated by compatibility_lifecycle tool.
+# Do not edit manually. Run hack/update-featuregates.sh to regenerate.
+
+`
+
+var testCurrentVersion = version.MustParse("1.32")
+
 func TestVerifyAlphabeticOrder(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -87,210 +95,8 @@ func TestVerifyAlphabeticOrder(t *testing.T) {
 	}
 }
 
-func TestVerifyOrUpdateFeatureListUnversioned(t *testing.T) {
-	featureListFileContent := `- name: AppArmorFields
-  versionedSpecs:
-  - default: true
-    lockToDefault: false
-    preRelease: Beta
-    version: ""
-- name: ClusterTrustBundleProjection
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: ""
-- name: CPUCFSQuotaPeriod
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: ""
-`
-	tests := []struct {
-		name                          string
-		goFileContent                 string
-		featureListFileContent        string
-		updatedFeatureListFileContent string
-		expectVerifyErr               bool
-		expectUpdateErr               bool
-	}{
-		{
-			name: "no change",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-}
-var otherFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-}
-`,
-			featureListFileContent:        featureListFileContent,
-			updatedFeatureListFileContent: featureListFileContent,
-		},
-		{
-			name: "semantically equivalent, formatting wrong",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-}
-var otherFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-}
-`,
-			featureListFileContent: `- name: AppArmorFields
-  versionedSpecs:
-    - default: true
-      lockToDefault: false
-      preRelease: Beta
-      version: ""
-- name: ClusterTrustBundleProjection
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: ""
-- name: CPUCFSQuotaPeriod
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: ""
-`,
-			updatedFeatureListFileContent: featureListFileContent,
-			expectVerifyErr:               true,
-		},
-		{
-			name: "same feature added twice with different lifecycle",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-}
-	var otherFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Alpha},
-}
-`,
-			featureListFileContent: featureListFileContent,
-			expectVerifyErr:        true,
-			expectUpdateErr:        true,
-		},
-		{
-			name: "new feature added",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-	SELinuxMount: {Default: false, PreRelease: featuregate.Alpha},
-}
-`,
-			featureListFileContent: featureListFileContent,
-			expectVerifyErr:        true,
-			expectUpdateErr:        true,
-		},
-		{
-			name: "delete feature",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-}
-`,
-			featureListFileContent: featureListFileContent,
-			expectVerifyErr:        true,
-			updatedFeatureListFileContent: `- name: AppArmorFields
-  versionedSpecs:
-  - default: true
-    lockToDefault: false
-    preRelease: Beta
-    version: ""
-- name: ClusterTrustBundleProjection
-  versionedSpecs:
-  - default: false
-    lockToDefault: false
-    preRelease: Alpha
-    version: ""
-`,
-		},
-		{
-			name: "update feature",
-			goFileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.GA},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	ClusterTrustBundleProjection: {Default: false, PreRelease: featuregate.Alpha},
-}
-			`,
-			featureListFileContent: featureListFileContent,
-			expectVerifyErr:        true,
-			expectUpdateErr:        true,
-		},
-	}
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			featureListFile := writeContentToTmpFile(t, "", "feature_list.yaml", tc.featureListFileContent)
-			tmpDir := filepath.Dir(featureListFile.Name())
-			_ = writeContentToTmpFile(t, tmpDir, "pkg/new_features.go", tc.goFileContent)
-			err := verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), false, false)
-			if tc.expectVerifyErr != (err != nil) {
-				t.Errorf("expectVerifyErr=%v, got err: %s", tc.expectVerifyErr, err)
-			}
-			err = verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), true, false)
-			if tc.expectUpdateErr != (err != nil) {
-				t.Errorf("expectUpdateErr=%v, got err: %s", tc.expectUpdateErr, err)
-			}
-			if tc.expectUpdateErr {
-				return
-			}
-			updatedFeatureListFileContent, err := os.ReadFile(featureListFile.Name())
-			if err != nil {
-				t.Fatal(err)
-			}
-			if diff := cmp.Diff(string(updatedFeatureListFileContent), tc.updatedFeatureListFileContent); diff != "" {
-				t.Errorf("updatedFeatureListFileContent does not match expected, diff=%s", diff)
-			}
-		})
-	}
-}
-
 func TestVerifyOrUpdateFeatureListVersioned(t *testing.T) {
-	featureListFileContent := `- name: APIListChunking
+	featureListFileContent := expectedHeader + `- name: APIListChunking
   versionedSpecs:
   - default: true
     lockToDefault: true
@@ -378,7 +184,7 @@ var otherFeatureGates = map[featuregate.Feature]featuregate.VersionedSpecs{
 	},
 }
 `,
-			featureListFileContent: `- name: APIListChunking
+			featureListFileContent: expectedHeader + `- name: APIListChunking
   versionedSpecs:
     - default: true
       lockToDefault: true
@@ -488,7 +294,7 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 `,
 			expectVerifyErr:        true,
 			featureListFileContent: featureListFileContent,
-			updatedFeatureListFileContent: `- name: APIListChunking
+			updatedFeatureListFileContent: expectedHeader + `- name: APIListChunking
   versionedSpecs:
   - default: true
     lockToDefault: true
@@ -519,7 +325,7 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 `,
 		},
 		{
-			name: "remove feature",
+			name: "not allowed to remove feature",
 			goFileContent: `
 package features
 
@@ -538,8 +344,9 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 }
 `,
 			expectVerifyErr:        true,
+			expectUpdateErr:        true,
 			featureListFileContent: featureListFileContent,
-			updatedFeatureListFileContent: `- name: APIListChunking
+			updatedFeatureListFileContent: expectedHeader + `- name: APIListChunking
   versionedSpecs:
   - default: true
     lockToDefault: true
@@ -582,7 +389,7 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 `,
 			expectVerifyErr:        true,
 			featureListFileContent: featureListFileContent,
-			updatedFeatureListFileContent: `- name: APIListChunking
+			updatedFeatureListFileContent: expectedHeader + `- name: APIListChunking
   versionedSpecs:
   - default: true
     lockToDefault: true
@@ -616,13 +423,13 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 			featureListFile := writeContentToTmpFile(t, "", "feature_list.yaml", tc.featureListFileContent)
 			tmpDir := filepath.Dir(featureListFile.Name())
 			_ = writeContentToTmpFile(t, tmpDir, "pkg/new_features.go", tc.goFileContent)
-			err := verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), false, true)
+			err := verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), testCurrentVersion, false)
 			if tc.expectVerifyErr != (err != nil) {
 				t.Errorf("expectVerifyErr=%v, got err: %s", tc.expectVerifyErr, err)
 			}
-			err = verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), true, true)
+			err = verifyOrUpdateFeatureList(tmpDir, filepath.Base(featureListFile.Name()), testCurrentVersion, true)
 			if tc.expectUpdateErr != (err != nil) {
-				t.Errorf("expectVerifyErr=%v, got err: %s", tc.expectVerifyErr, err)
+				t.Errorf("expectUpdateErr=%v, got err: %s", tc.expectUpdateErr, err)
 			}
 			if tc.expectUpdateErr {
 				return
@@ -638,162 +445,6 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 	}
 }
 
-func TestExtractFeatureInfoListFromFile(t *testing.T) {
-	tests := []struct {
-		name             string
-		fileContent      string
-		expectedFeatures []featureInfo
-	}{
-		{
-			name: "map in var",
-			fileContent: `
-package features
-
-import (
-	"k8s.io/apimachinery/pkg/util/version"
-	genericfeatures "k8s.io/apiserver/pkg/features"
-	"k8s.io/component-base/featuregate"
-)
-var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: featuregate.Beta},
-	CPUCFSQuotaPeriod: {Default: false, PreRelease: featuregate.Alpha},
-	genericfeatures.AggregatedDiscoveryEndpoint: {Default: false, PreRelease: featuregate.Alpha},
-}
-			`,
-			expectedFeatures: []featureInfo{
-				{
-					Name:     "AppArmorFields",
-					FullName: "AppArmorFields",
-					VersionedSpecs: []featureSpec{
-						{Default: true, PreRelease: "Beta"},
-					},
-				},
-				{
-					Name:     "CPUCFSQuotaPeriod",
-					FullName: "CPUCFSQuotaPeriod",
-					VersionedSpecs: []featureSpec{
-						{Default: false, PreRelease: "Alpha"},
-					},
-				},
-				{
-					Name:     "AggregatedDiscoveryEndpoint",
-					FullName: "genericfeatures.AggregatedDiscoveryEndpoint",
-					VersionedSpecs: []featureSpec{
-						{Default: false, PreRelease: "Alpha"},
-					},
-				},
-			},
-		},
-		{
-			name: "map in var with alias",
-			fileContent: `
-package features
-
-import (
-	"k8s.io/apimachinery/pkg/util/version"
-	genericfeatures "k8s.io/apiserver/pkg/features"
-	fg "k8s.io/component-base/featuregate"
-)
-const (
-    CPUCFSQuotaPeriodDefault = false
-)
-var defaultVersionedKubernetesFeatureGates = map[fg.Feature]fg.FeatureSpec{
-	AppArmorFields: {Default: true, PreRelease: fg.Beta},
-	CPUCFSQuotaPeriod: {Default: CPUCFSQuotaPeriodDefault, PreRelease: fg.Alpha},
-	genericfeatures.AggregatedDiscoveryEndpoint: {Default: false, PreRelease: fg.Alpha},
-}
-			`,
-			expectedFeatures: []featureInfo{
-				{
-					Name:     "AppArmorFields",
-					FullName: "AppArmorFields",
-					VersionedSpecs: []featureSpec{
-						{Default: true, PreRelease: "Beta"},
-					},
-				},
-				{
-					Name:     "CPUCFSQuotaPeriod",
-					FullName: "CPUCFSQuotaPeriod",
-					VersionedSpecs: []featureSpec{
-						{Default: false, PreRelease: "Alpha"},
-					},
-				},
-				{
-					Name:     "AggregatedDiscoveryEndpoint",
-					FullName: "genericfeatures.AggregatedDiscoveryEndpoint",
-					VersionedSpecs: []featureSpec{
-						{Default: false, PreRelease: "Alpha"},
-					},
-				},
-			},
-		},
-		{
-			name: "map in function return statement",
-			fileContent: `
-package features
-
-import (
-	"k8s.io/component-base/featuregate"
-)
-
-const (
-	ComponentSLIs featuregate.Feature = "ComponentSLIs"
-)
-
-func featureGates() map[featuregate.Feature]featuregate.FeatureSpec {
-	return map[featuregate.Feature]featuregate.FeatureSpec{
-		ComponentSLIs: {Default: true, PreRelease: featuregate.Beta},
-	}
-}
-			`,
-			expectedFeatures: []featureInfo{
-				{
-					Name:     "ComponentSLIs",
-					FullName: "ComponentSLIs",
-					VersionedSpecs: []featureSpec{
-						{Default: true, PreRelease: "Beta"},
-					},
-				},
-			},
-		},
-		// 		{
-		// 			name: "map in function call",
-		// 			fileContent: `
-		// package features
-
-		// import (
-		// 	"k8s.io/component-base/featuregate"
-		// )
-
-		// const (
-		// 	ComponentSLIs featuregate.Feature = "ComponentSLIs"
-		// )
-
-		// func featureGates() featuregate.FeatureGate {
-		// 	featureGate := featuregate.NewFeatureGate()
-		// 	_ = featureGate.Add(map[featuregate.Feature]featuregate.FeatureSpec{
-		// 		ComponentSLIs: {
-		// 			Default: true, PreRelease: featuregate.Beta}})
-		// 	return featureGate
-		// }
-		// 			`,
-		// 		},
-	}
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			newFile := writeContentToTmpFile(t, "", "new_features.go", tc.fileContent)
-			fset := token.NewFileSet()
-			features, err := extractFeatureInfoListFromFile(fset, newFile.Name(), false)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if diff := cmp.Diff(features, tc.expectedFeatures); diff != "" {
-				t.Errorf("File contents: got=%v, want=%v, diff=%s", features, tc.expectedFeatures, diff)
-			}
-		})
-	}
-}
-
 func TestExtractFeatureInfoListFromFileVersioned(t *testing.T) {
 	tests := []struct {
 		name             string
@@ -961,7 +612,7 @@ func featureGates() map[featuregate.Feature]featuregate.VersionedSpecs {
 		t.Run(tc.name, func(t *testing.T) {
 			newFile := writeContentToTmpFile(t, "", "new_features.go", tc.fileContent)
 			fset := token.NewFileSet()
-			features, err := extractFeatureInfoListFromFile(fset, newFile.Name(), true)
+			features, err := extractFeatureInfoListFromFile(fset, newFile.Name())
 			if tc.expectErr {
 				if err == nil {
 					t.Fatal("expect err")
@@ -1003,7 +654,6 @@ func writeContentToTmpFile(t *testing.T, tmpDir, fileName, fileContent string) *
 	if err != nil {
 		t.Fatal(err)
 	}
-	fmt.Printf("sizhangDebug: Written tmp file %s\n", tmpfile.Name())
 	return tmpfile
 }
 
@@ -1087,3 +737,160 @@ func TestParseFeatureSpec(t *testing.T) {
 		})
 	}
 }
+func TestVerifyFeatureRemoval(t *testing.T) {
+	tests := []struct {
+		name             string
+		featureList      []featureInfo
+		baseFeatureList  []featureInfo
+		currentVersion   *version.Version
+		thresholdVersion *version.Version
+		expectErr        bool
+		expectedErrMsg   string
+	}{
+		{
+			name: "no features removed",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			currentVersion: version.MustParse("1.1"),
+			expectErr:      false,
+		},
+		{
+			name: "alpha feature removed",
+			featureList: []featureInfo{
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			currentVersion: version.MustParse("1.1"),
+			expectErr:      false,
+		},
+		{
+			name: "beta feature removed",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureB", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Beta"}}},
+			},
+			currentVersion: version.MustParse("1.1"),
+			expectErr:      true,
+			expectedErrMsg: "feature FeatureB cannot be removed while in beta",
+		},
+		{
+			name: "GA feature removed before allowed version",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureC", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "GA", LockToDefault: true}}},
+			},
+			currentVersion: version.MustParse("1.2"),
+			expectErr:      true,
+			expectedErrMsg: "feature FeatureC cannot be removed until version 1.3 (required for emulation support)",
+		},
+		{
+			name: "GA feature removed after allowed version",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureC", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "GA", LockToDefault: true}}},
+			},
+			currentVersion: version.MustParse("1.4"),
+			expectErr:      false,
+		},
+		{
+			name: "feature with no version specs",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureD", VersionedSpecs: []featureSpec{}},
+			},
+			currentVersion: version.MustParse("1.1"),
+			expectErr:      true,
+			expectedErrMsg: "feature FeatureD has no version specs",
+		},
+		{
+			name: "feature with invalid version",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureE", VersionedSpecs: []featureSpec{{Version: "invalid", PreRelease: "GA", LockToDefault: true}}},
+			},
+			currentVersion: version.MustParse("1.1"),
+			expectErr:      true,
+			expectedErrMsg: "invalid version \"invalid\" for feature FeatureE",
+		},
+		{
+			name: "GA feature not locked to default",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureC", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "GA"}}},
+			},
+			currentVersion: version.MustParse("1.4"),
+			expectErr:      true,
+			expectedErrMsg: "feature FeatureC cannot be removed because it is in GA or Deprecated state and is not locked to default",
+		},
+		{
+			name: "Deprecated feature not locked to default",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureD", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Deprecated"}}},
+			},
+			currentVersion: version.MustParse("1.4"),
+			expectErr:      true,
+			expectedErrMsg: "feature FeatureD cannot be removed because it is in GA or Deprecated state and is not locked to default",
+		},
+		{
+			name: "GA feature removed at threshold version",
+			featureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+			},
+			baseFeatureList: []featureInfo{
+				{Name: "FeatureA", VersionedSpecs: []featureSpec{{Version: "1.0", PreRelease: "Alpha"}}},
+				{Name: "FeatureC", VersionedSpecs: []featureSpec{{Version: "1.4", PreRelease: "GA", LockToDefault: true}}},
+			},
+			currentVersion:   version.MustParse("1.5"),
+			thresholdVersion: version.MustParse("1.4"),
+			expectErr:        false,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := verifyFeatureRemoval(tc.featureList, tc.baseFeatureList, tc.currentVersion, tc.thresholdVersion)
+			if tc.expectErr {
+				if err == nil {
+					t.Fatalf("expected error, got nil")
+				}
+				if !strings.Contains(err.Error(), tc.expectedErrMsg) {
+					t.Fatalf("expected error message to contain %q, got %q", tc.expectedErrMsg, err.Error())
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+		})
+	}
+}

test/compatibility_lifecycle/cmd/root.go

@@ -23,9 +23,9 @@ import (
 )
 
 var rootCmd = &cobra.Command{
-	Use:   "static-analysis",
+	Use:   "compatibility-lifecycle",
-	Short: "static-analysis",
+	Short: "compatibility-lifecycle",
-	Long:  `static-analysis runs static analysis of go code.`,
+	Long:  `compatibility-lifecycle runs verification for compatibility lifecycle.`,
 }
 
 func Execute() {

test/compatibility_lifecycle/main.go

@@ -16,7 +16,7 @@ limitations under the License.
 
 package main
 
-import "k8s.io/kubernetes/test/featuregates_linter/cmd"
+import "k8s.io/kubernetes/test/compatibility_lifecycle/cmd"
 
 func main() {
 	cmd.Execute()

test/compatibility_lifecycle/reference/versioned_feature_list.yaml

@@ -1,3 +1,6 @@
+# This file is generated by compatibility_lifecycle tool.
+# Do not edit manually. Run hack/update-featuregates.sh to regenerate.
+
 - name: AllowDNSOnlyNodeCSR
   versionedSpecs:
   - default: true

test/featuregates_linter/README.md

@@ -1,8 +0,0 @@
-This directory contains static analysis scripts for verify functions.
-
-Currently, the following commands are implemented:
-```
-go run test/featuregates_linter/main.go feature-gates verify-no-new-unversioned --new-features-file="${new_features_file}" --old-features-file="${old_features_file}"
-
-go run test/featuregates_linter/main.go feature-gates verify-alphabetic-order --features-file="${features_file}"
-```