Add a tool to detect possible unused language keys and remove those which can be confirmed

.github/workflows/pull-compliance.yml

@@ -178,6 +178,16 @@ jobs:
           GOOS: linux
           GOARCH: 386
 
+  translations:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          check-latest: true
+      - run: make check-locales
+
   docs:
     if: needs.files-changed.outputs.docs == 'true' || needs.files-changed.outputs.actions == 'true'
     needs: files-changed

Makefile

@@ -884,6 +884,11 @@ update-translations:
 	mv ./translations/*.ini ./options/locale/
 	rmdir ./translations
 
+.PHONY: check-locales
+check-locales:
+	@echo "Checking translations..."
+	$(GO) run build/check-locales.go
+
 .PHONY: generate-gitignore
 generate-gitignore: ## update gitignore files
 	$(GO) run build/generate-gitignores.go

build/check-locales.go

@@ -0,0 +1,124 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build ignore
+
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/gobwas/glob"
+)
+
+func searchTranslationKeyInDirs(keys []string) ([]bool, error) {
+	res := make([]bool, len(keys))
+	for _, dir := range []string{
+		"cmd",
+		"models",
+		"modules",
+		"routers",
+		"services",
+		"templates",
+	} {
+		if err := searchTranslationKeyInDir(dir, keys, &res); err != nil {
+			return nil, err
+		}
+	}
+	return res, nil
+}
+
+func searchTranslationKeyInDir(dir string, keys []string, res *[]bool) error {
+	return filepath.WalkDir(dir, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() ||
+			(!strings.HasSuffix(d.Name(), ".go") && !strings.HasSuffix(d.Name(), ".tmpl")) ||
+			strings.HasSuffix(d.Name(), "_test.go") { // don't search in test files
+			return nil
+		}
+
+		bs, err := os.ReadFile(path)
+		if err != nil {
+			return err
+		}
+		for i, key := range keys {
+			if !(*res)[i] && strings.Contains(string(bs), `"`+key+`"`) {
+				(*res)[i] = true
+			}
+		}
+		return nil
+	})
+}
+
+var whitelist = []string{
+	"repo.signing.wont_sign.*",
+	"repo.issues.role.*",
+	"repo.commitstatus.*",
+	"admin.dashboard.*",
+	"admin.dashboard.cron.*",
+	"admin.dashboard.task.*",
+	"repo.migrate.*.description",
+	"actions.runners.status.*",
+	"projects.*.display_name",
+	"admin.notices.*",
+	"form.NewBranchName", // FIXME: used in integration tests only
+}
+
+func isWhitelisted(key string) bool {
+	for _, w := range whitelist {
+		if glob.MustCompile(w).Match(key) {
+			return true
+		}
+	}
+	return false
+}
+
+func main() {
+	if len(os.Args) != 1 {
+		println("usage: clean-locales")
+		os.Exit(1)
+	}
+
+	iniFile, err := setting.NewConfigProviderForLocale("options/locale/locale_en-US.ini")
+	if err != nil {
+		panic(err)
+	}
+
+	keys := []string{}
+	for _, section := range iniFile.Sections() {
+		for _, key := range section.Keys() {
+			var trKey string
+			if section.Name() == "" || section.Name() == "DEFAULT" {
+				trKey = key.Name()
+			} else {
+				trKey = section.Name() + "." + key.Name()
+			}
+			if isWhitelisted(trKey) {
+				continue
+			}
+			keys = append(keys, trKey)
+		}
+	}
+
+	results, err := searchTranslationKeyInDirs(keys)
+	if err != nil {
+		panic(err)
+	}
+
+	var found bool
+	for i, result := range results {
+		if !result {
+			found = true
+			println("unused locale key:", keys[i])
+		}
+	}
+	if found {
+		os.Exit(1) // exit with error if any unused locale key is found
+	}
+}