chore: add modernizer linter (#11936)

- Go has a suite of small linters that helps with modernizing Go code by using newer functions and catching small mistakes, https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize.
- Enable this linter in golangci-lint.
- There's also [`go fix`](https://go.dev/blog/gofix), which is not yet released as a linter in golangci-lint: https://github.com/golangci/golangci-lint/pull/6385

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11936
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

modules/setting/config.go

@@ -4,6 +4,7 @@
 package setting
 
 import (
+	"strings"
 	"sync"
 
 	"forgejo.org/modules/log"
@@ -23,11 +24,11 @@ type OpenWithEditorApp struct {
 type OpenWithEditorAppsType []OpenWithEditorApp
 
 func (t OpenWithEditorAppsType) ToTextareaString() string {
-	ret := ""
+	var ret strings.Builder
 	for _, app := range t {
-		ret += app.DisplayName + " = " + app.OpenURL + "\n"
+		ret.WriteString(app.DisplayName + " = " + app.OpenURL + "\n")
 	}
-	return ret
+	return ret.String()
 }
 
 func DefaultOpenWithEditorApps() OpenWithEditorAppsType {

modules/setting/config_env.go

@@ -51,10 +51,10 @@ func decodeEnvSectionKey(encoded string) (ok bool, section, key string) {
 	for _, unescapeIdx := range escapeStringIndices {
 		preceding := encoded[last:unescapeIdx[0]]
 		if !inKey {
-			if splitter := strings.Index(preceding, "__"); splitter > -1 {
-				section += preceding[:splitter]
+			if before, after, ok := strings.Cut(preceding, "__"); ok {
+				section += before
 				inKey = true
-				key += preceding[splitter+2:]
+				key += after
 			} else {
 				section += preceding
 			}
@@ -77,9 +77,9 @@ func decodeEnvSectionKey(encoded string) (ok bool, section, key string) {
 	}
 	remaining := encoded[last:]
 	if !inKey {
-		if splitter := strings.Index(remaining, "__"); splitter > -1 {
-			section += remaining[:splitter]
-			key += remaining[splitter+2:]
+		if before, after, ok := strings.Cut(remaining, "__"); ok {
+			section += before
+			key += after
 		} else {
 			section += remaining
 		}
@@ -113,25 +113,24 @@ func decodeEnvironmentKey(prefixRegexp *regexp.Regexp, suffixFile, envKey string
 func EnvironmentToConfig(cfg ConfigProvider, envs []string) (changed bool) {
 	prefixRegexp := regexp.MustCompile(EnvConfigKeyPrefixGitea)
 	for _, kv := range envs {
-		idx := strings.IndexByte(kv, '=')
-		if idx < 0 {
+		before, after, ok0 := strings.Cut(kv, "=")
+		if !ok0 {
 			continue
 		}
 
 		// parse the environment variable to config section name and key name
-		envKey := kv[:idx]
-		envValue := kv[idx+1:]
+		envKey := before
+		keyValue := after
 		ok, sectionName, keyName, useFileValue := decodeEnvironmentKey(prefixRegexp, EnvConfigKeySuffixFile, envKey)
 		if !ok {
 			continue
 		}
 
 		// use environment value as config value, or read the file content as value if the key indicates a file
-		keyValue := envValue
 		if useFileValue {
-			fileContent, err := os.ReadFile(envValue)
+			fileContent, err := os.ReadFile(keyValue)
 			if err != nil {
-				log.Error("Error reading file for %s : %v", envKey, envValue, err)
+				log.Error("Error reading file for %s : %v", envKey, keyValue, err)
 				continue
 			}
 			if bytes.HasSuffix(fileContent, []byte("\r\n")) {

modules/setting/indexer.go

@@ -108,7 +108,7 @@ func loadIndexerFrom(rootCfg ConfigProvider) {
 // IndexerGlobFromString parses a comma separated list of patterns and returns a glob.Glob slice suited for repo indexing
 func IndexerGlobFromString(globstr string) []Glob {
 	extarr := make([]Glob, 0, 10)
-	for _, expr := range strings.Split(strings.ToLower(globstr), ",") {
+	for expr := range strings.SplitSeq(strings.ToLower(globstr), ",") {
 		expr = strings.TrimSpace(expr)
 		if expr != "" {
 			if g, err := glob.Compile(expr, '.', '/'); err != nil {

modules/setting/log.go

@@ -269,8 +269,8 @@ func initLoggerByName(manager *log.LoggerManager, rootCfg ConfigProvider, logger
 	}
 
 	var eventWriters []log.EventWriter
-	modes := strings.Split(modeVal, ",")
-	for _, modeName := range modes {
+	modes := strings.SplitSeq(modeVal, ",")
+	for modeName := range modes {
 		modeName = strings.TrimSpace(modeName)
 		if modeName == "" {
 			continue

modules/setting/markup.go

@@ -85,8 +85,8 @@ func loadMarkupFrom(rootCfg ConfigProvider) {
 func newMarkupSanitizer(name string, sec ConfigSection) {
 	rule, ok := createMarkupSanitizerRule(name, sec)
 	if ok {
-		if strings.HasPrefix(name, "sanitizer.") {
-			names := strings.SplitN(strings.TrimPrefix(name, "sanitizer."), ".", 2)
+		if after, ok0 := strings.CutPrefix(name, "sanitizer."); ok0 {
+			names := strings.SplitN(after, ".", 2)
 			name = names[0]
 		}
 		for _, renderer := range ExternalMarkupRenderers {

modules/setting/mirror.go

@@ -48,11 +48,7 @@ func loadMirrorFrom(rootCfg ConfigProvider) {
 		Mirror.MinInterval = 1 * time.Minute
 	}
 	if Mirror.DefaultInterval < Mirror.MinInterval {
-		if time.Hour*8 < Mirror.MinInterval {
-			Mirror.DefaultInterval = Mirror.MinInterval
-		} else {
-			Mirror.DefaultInterval = time.Hour * 8
-		}
+		Mirror.DefaultInterval = max(time.Hour*8, Mirror.MinInterval)
 		log.Warn("Mirror.DefaultInterval is less than Mirror.MinInterval, set to %s", Mirror.DefaultInterval.String())
 	}
 }

modules/setting/storage.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"path/filepath"
+	"slices"
 	"strings"
 )
 
@@ -27,12 +28,7 @@ var storageTypes = []StorageType{
 
 // IsValidStorageType returns true if the given storage type is valid
 func IsValidStorageType(storageType StorageType) bool {
-	for _, t := range storageTypes {
-		if t == storageType {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(storageTypes, storageType)
 }
 
 // MinioStorageConfig represents the configuration for a minio storage