add modernize linter (#12842)

Signed-off-by: Jenny Shu <[email protected]>

Author: jenshu

.custom-gcl.yml

@@ -1,4 +1,4 @@
-version: v2.5.0
+version: v2.6.1
 name: golangci-lint-custom
 destination: _output
 plugins:

.golangci.yaml

@@ -22,6 +22,7 @@ linters:
     - krtequals
     - kubeapilinter
     - misspell
+    - modernize
     - nakedret
     - predeclared
     - promlinter
@@ -106,6 +107,10 @@ linters:
     misspell:
       ignore-rules:
         - kgateway
+    modernize:
+      disable:
+        # disabled because modernize gets confused with conflicting edits. we can probably rely on the kube api linter instead for this one.
+        - omitzero
     nakedret:
       # The team consensus is that naked returns hinder the readability of the code.
       # However, named return values can still be useful as documentation for certain scenarios.

api/settings/settings_test.go

@@ -287,9 +287,9 @@ var (
 
 // expectedEnvVars returns a map of all the env vars that should be set for the given Settings value.
 // The value of the map is the default value of the field.
-func expectedEnvVars(settingsValue reflect.Value) map[string]interface{} {
+func expectedEnvVars(settingsValue reflect.Value) map[string]any {
 	// This is a modified version of the code in https://github.com/kelseyhightower/envconfig/blob/7834011875d613aec60c606b52c2b0fe8949fe91/envconfig.go#L102-L128
-	expectedEnvVars := make(map[string]interface{}, settingsValue.NumField())
+	expectedEnvVars := make(map[string]any, settingsValue.NumField())
 	for i := 0; i < settingsValue.NumField(); i++ {
 		fieldType := settingsValue.Type().Field(i)
 		splitWords := fieldType.Tag.Get("split_words") == "true"

internal/envoyinit/pkg/downward/downward.go

@@ -131,8 +131,8 @@ func (di *downwardInjectable) PodAnnotations() map[string]string { return di.pod
 func parse(data []byte) map[string]string {
 	m := map[string]string{}
 
-	lines := strings.Split(string(data), "\n")
-	for _, l := range lines {
+	lines := strings.SplitSeq(string(data), "\n")
+	for l := range lines {
 		l = strings.TrimSpace(l)
 		parts := strings.SplitN(l, "=", 2)
 		if len(parts) != 2 {

internal/kgateway/admin/logging.go

@@ -20,7 +20,8 @@ func getLoggingDescription() string {
 	componentLevels := logging.GetComponentLevels()
 
 	// Build component selector
-	componentSelector := `<select id="componentselector">`
+	var componentSelector strings.Builder
+	componentSelector.WriteString(`<select id="componentselector">`)
 	// Ensure consistent order for the selector
 	components := make([]string, 0, len(componentLevels))
 	for comp := range componentLevels {
@@ -29,29 +30,31 @@ func getLoggingDescription() string {
 	sort.Strings(components) // Sort alphabetically
 
 	for _, comp := range components {
-		componentSelector += fmt.Sprintf(`<option value="%s">%s (Current: %s)</option>`, comp, comp, logging.LevelToString(componentLevels[comp]))
+		componentSelector.WriteString(fmt.Sprintf(`<option value="%s">%s (Current: %s)</option>`, comp, comp, logging.LevelToString(componentLevels[comp])))
 	}
-	componentSelector += `</select>`
+	componentSelector.WriteString(`</select>`)
 
 	// Build level selector
-	levelSelector := `<select id="loglevelselector">`
+	var levelSelector strings.Builder
+	levelSelector.WriteString(`<select id="loglevelselector">`)
 	supportedLogLevels := []string{"trace", "debug", "info", "warn", "error"}
 	for _, level := range supportedLogLevels {
-		levelSelector += fmt.Sprintf(`<option value="%s">%s</option>`, level, strings.ToUpper(level))
+		levelSelector.WriteString(fmt.Sprintf(`<option value="%s">%s</option>`, level, strings.ToUpper(level)))
 	}
-	levelSelector += `</select>`
+	levelSelector.WriteString(`</select>`)
 
 	// Display current levels
-	currentLevelsDisplay := "<h4>Current Levels:</h4><ul>"
+	var currentLevelsDisplay strings.Builder
+	currentLevelsDisplay.WriteString("<h4>Current Levels:</h4><ul>")
 	for _, comp := range components {
-		currentLevelsDisplay += fmt.Sprintf("<li>%s: %s</li>", comp, logging.LevelToString(componentLevels[comp]))
+		currentLevelsDisplay.WriteString(fmt.Sprintf("<li>%s: %s</li>", comp, logging.LevelToString(componentLevels[comp])))
 	}
-	currentLevelsDisplay += "</ul><hr/>"
+	currentLevelsDisplay.WriteString("</ul><hr/>")
 
-	return currentLevelsDisplay + `Set log level for a specific component.<br/>
+	return currentLevelsDisplay.String() + `Set log level for a specific component.<br/>
 
-Component: ` + componentSelector + `
-Level: ` + levelSelector + `
+Component: ` + componentSelector.String() + `
+Level: ` + levelSelector.String() + `
 
 <button onclick="setlevel()">Set Component Level</button>
 <button onclick="setAllLevels()">Set All Levels</button>

internal/kgateway/admin/response.go

@@ -9,8 +9,8 @@ import (
 // It allows us to encapsulate data and errors together, so that if an issue occurs during the request,
 // we can get access to all the relevant information
 type SnapshotResponseData struct {
-	Data  interface{} `json:"data"`
-	Error error       `json:"error"`
+	Data  any   `json:"data"`
+	Error error `json:"error"`
 }
 
 // OutputFormat identifies the format to output an object
@@ -38,8 +38,8 @@ func (r SnapshotResponseData) Format(format OutputFormat) ([]byte, error) {
 		errorMsg = r.Error.Error()
 	}
 	anon := struct {
-		Data  interface{} `json:"data"`
-		Error string      `json:"error"`
+		Data  any    `json:"data"`
+		Error string `json:"error"`
 	}{
 		Data:  r.Data,
 		Error: errorMsg,
@@ -61,7 +61,7 @@ func (r SnapshotResponseData) MarshalJSONString() string {
 }
 
 // formatOutput formats a generic object into the specified output format
-func formatOutput(format OutputFormat, genericOutput interface{}) ([]byte, error) {
+func formatOutput(format OutputFormat, genericOutput any) ([]byte, error) {
 	switch format {
 	case Json:
 		return json.MarshalIndent(genericOutput, "", "    ")
@@ -76,7 +76,7 @@ func formatOutput(format OutputFormat, genericOutput interface{}) ([]byte, error
 	}
 }
 
-func completeSnapshotResponse(data interface{}) SnapshotResponseData {
+func completeSnapshotResponse(data any) SnapshotResponseData {
 	return SnapshotResponseData{
 		Data:  data,
 		Error: nil,

internal/kgateway/admin/xds_snapshot.go

@@ -19,7 +19,7 @@ func addXdsSnapshotHandler(path string, mux *http.ServeMux, profiles map[string]
 
 func getXdsSnapshotDataFromCache(xdsCache cache.SnapshotCache) SnapshotResponseData {
 	cacheKeys := xdsCache.GetStatusKeys()
-	cacheEntries := make(map[string]interface{}, len(cacheKeys))
+	cacheEntries := make(map[string]any, len(cacheKeys))
 
 	for _, k := range cacheKeys {
 		xdsSnapshot, err := getXdsSnapshot(xdsCache, k)

internal/kgateway/agentgatewaysyncer/agentgateway_testutils.go

@@ -76,7 +76,7 @@ func (tr *translationResult) MarshalJSON() ([]byte, error) {
 	}
 
 	// Create a map to hold the marshaled fields
-	result := make(map[string]interface{})
+	result := make(map[string]any)
 
 	// Marshal each field using protojson
 	if len(tr.Routes) > 0 {
@@ -257,14 +257,14 @@ func (tr *translationResult) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
-func marshalProtoMessages[T proto.Message](messages []T, m protojson.MarshalOptions) ([]interface{}, error) {
-	var result []interface{}
+func marshalProtoMessages[T proto.Message](messages []T, m protojson.MarshalOptions) ([]any, error) {
+	var result []any
 	for _, msg := range messages {
 		data, err := m.Marshal(msg)
 		if err != nil {
 			return nil, err
 		}
-		var jsonObj interface{}
+		var jsonObj any
 		if err := json.Unmarshal(data, &jsonObj); err != nil {
 			return nil, err
 		}
@@ -444,7 +444,7 @@ func sortTranslationResult(tr *translationResult) *translationResult {
 	return tr
 }
 
-func ReadYamlFile(file string, out interface{}) error {
+func ReadYamlFile(file string, out any) error {
 	data, err := os.ReadFile(file)
 	if err != nil {
 		return err

internal/kgateway/agentgatewaysyncer/krtxds/pushqueue_test.go

@@ -61,7 +61,7 @@ func ExpectDequeue(t *testing.T, p *PushQueue, expected *Connection) {
 
 func TestProxyQueue(t *testing.T) {
 	proxies := make([]*Connection, 0, 100)
-	for p := 0; p < 100; p++ {
+	for p := range 100 {
 		conn := &Connection{}
 		conn.SetID(fmt.Sprintf("proxy-%d", p))
 		proxies = append(proxies, conn)
@@ -137,11 +137,9 @@ func TestProxyQueue(t *testing.T) {
 		defer p.ShutDown()
 
 		wg := &sync.WaitGroup{}
-		wg.Add(1)
-		go func() {
+		wg.Go(func() {
 			ExpectDequeue(t, p, proxies[0])
-			wg.Done()
-		}()
+		})
 		time.Sleep(time.Millisecond * 50)
 		p.Enqueue(proxies[0], &PushRequest{})
 		wg.Wait()
@@ -214,13 +212,13 @@ func TestProxyQueue(t *testing.T) {
 		// We will trigger many pushes for eds services to each proxy. In the end we will expect
 		// all of these to be dequeue, but order is not deterministic.
 		expected := sets.String{}
-		for eds := 0; eds < 100; eds++ {
+		for eds := range 100 {
 			for _, pr := range proxies {
 				expected.Insert(key(pr, fmt.Sprintf("%d", eds)))
 			}
 		}
 		go func() {
-			for eds := 0; eds < 100; eds++ {
+			for eds := range 100 {
 				for _, pr := range proxies {
 					p.Enqueue(pr, &PushRequest{
 						ConfigsUpdated: map[TypeUrl]sets.String{
@@ -271,12 +269,12 @@ func TestProxyQueue(t *testing.T) {
 		// We will trigger many pushes for eds services to the proxy. In the end we will expect
 		// all of these to be dequeue, but order is deterministic.
 		expected := make([]string, 100)
-		for eds := 0; eds < 100; eds++ {
+		for eds := range 100 {
 			expected[eds] = fmt.Sprintf("%d", eds)
 		}
 		go func() {
 			// send to pushQueue
-			for eds := 0; eds < 100; eds++ {
+			for eds := range 100 {
 				p.Enqueue(con, &PushRequest{
 					ConfigsUpdated: map[TypeUrl]sets.String{
 						"type1": sets.New(fmt.Sprintf("%d", eds)),

internal/kgateway/agentgatewaysyncer/krtxds/xds.go

@@ -1037,20 +1037,20 @@ func debounce(ch chan *PushRequest, stopCh <-chan struct{}, opts DebounceOptions
 }
 
 func configsUpdated(req *PushRequest) string {
-	configs := ""
+	var configs strings.Builder
 	count := 0
 	for _, keys := range req.ConfigsUpdated {
 		count += len(keys)
 		for key := range keys {
-			configs += key
+			configs.WriteString(key)
 			break
 		}
 	}
 	if count > 1 {
 		more := " and " + strconv.Itoa(count-1) + " more configs"
-		configs += more
+		configs.WriteString(more)
 	}
-	return configs
+	return configs.String()
 }
 
 func nonce(noncePrefix string) string {