fix: meta language resolution and key leak

frontend/app/core/lib/seo-meta.ts

@@ -1,22 +1,57 @@
 import { translate, type Language } from "@/core/lib/i18n";
 import { APP_URL } from "@/core/lib/config";
 
+export const DEFAULT_LANGUAGE: Language = "fr";
+
+const SUPPORTED_LANGUAGES: ReadonlySet<string> = new Set([
+    "fr", "en", "es", "it", "de", "pt", "ru", "pl", "zh-CN", "ja", "ko", "nl",
+]);
+
+function isSupportedLanguage(lang: unknown): lang is Language {
+    return typeof lang === "string" && SUPPORTED_LANGUAGES.has(lang);
+}
+
 /**
  * Langue résolue côté serveur par le loader root (cookie puis Accept-Language).
  * Utilisée par les meta() SSR pour rendre title/description dans la bonne langue.
+ *
+ * Attention : dans les meta(), les matches React Router exposent les données
+ * sous `loaderData` (pas `data`). Lire `.data` renvoie toujours `undefined` et
+ * force le fallback français — puis des clés i18n brutes côté client quand le
+ * dictionnaire français n'y est pas chargé.
  */
 export function resolveMetaLanguage(
-    matches: Array<{ id?: string; data?: unknown }> | undefined
+    matches: Array<{ id?: string; loaderData?: unknown }> | undefined
 ): Language {
-    const rootData = matches?.find((m) => m.id === "root")?.data as
-        | { serverLanguage?: Language }
+    const rootData = matches?.find((m) => m.id === "root")?.loaderData as
+        | { serverLanguage?: unknown }
         | undefined;
-    return rootData?.serverLanguage ?? "fr";
+    const lang = rootData?.serverLanguage ?? DEFAULT_LANGUAGE;
+    return isSupportedLanguage(lang) ? lang : DEFAULT_LANGUAGE;
+}
+
+/**
+ * Traduction sûre pour les balises SEO : ne renvoie JAMAIS la clé brute.
+ * Chaîne de fallback : langue demandée → langue par défaut → chaîne vide.
+ * Une clé i18n dans un <title> serait indexée telle quelle par Google.
+ */
+export function translateMeta(
+    lang: Language,
+    path: string,
+    replacements?: Record<string, string>
+): string {
+    const hit = translate(lang, path, replacements);
+    if (hit !== path) return hit;
+    if (lang !== DEFAULT_LANGUAGE) {
+        const fallback = translate(DEFAULT_LANGUAGE, path, replacements);
+        if (fallback !== path) return fallback;
+    }
+    return "";
 }
 
 /** Titre suffixé du nom du site, ex. "Comparaison de serveurs | Minecraft-Stats". */
 export function siteTitle(lang: Language, titleKey: string): string {
-    return `${translate(lang, titleKey)} | Minecraft-Stats`;
+    return `${translateMeta(lang, titleKey)} | Minecraft-Stats`;
 }
 
 /** Tronque une description au-delà de `max` caractères, sans couper en plein mot. */

frontend/app/pages/LegalNotice.tsx

@@ -2,14 +2,13 @@
 import type { MetaFunction } from "react-router"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { legalReplacements } from "@/core/lib/legal-info"
-import { translate } from "@/core/lib/i18n"
-import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription } from "@/core/lib/seo-meta"
+import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription, translateMeta } from "@/core/lib/seo-meta"
 
 export const meta: MetaFunction = ({ matches }) => {
     const lang = resolveMetaLanguage(matches)
     return staticPageMeta({
         title: siteTitle(lang, "legal.notice.title"),
-        description: truncateDescription(translate(lang, "legal.notice.p1", legalReplacements)),
+        description: truncateDescription(translateMeta(lang, "legal.notice.p1", legalReplacements)),
         path: "/legal",
     })
 }

frontend/app/pages/Privacy.tsx

@@ -2,14 +2,13 @@
 import type { MetaFunction } from "react-router"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { legalReplacements } from "@/core/lib/legal-info"
-import { translate } from "@/core/lib/i18n"
-import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription } from "@/core/lib/seo-meta"
+import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription, translateMeta } from "@/core/lib/seo-meta"
 
 export const meta: MetaFunction = ({ matches }) => {
     const lang = resolveMetaLanguage(matches)
     return staticPageMeta({
         title: siteTitle(lang, "legal.privacy.title"),
-        description: truncateDescription(translate(lang, "legal.privacy.p1", legalReplacements)),
+        description: truncateDescription(translateMeta(lang, "legal.privacy.p1", legalReplacements)),
         path: "/privacy",
     })
 }

frontend/app/pages/Terms.tsx

@@ -2,14 +2,13 @@
 import type { MetaFunction } from "react-router"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { legalReplacements } from "@/core/lib/legal-info"
-import { translate } from "@/core/lib/i18n"
-import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription } from "@/core/lib/seo-meta"
+import { resolveMetaLanguage, siteTitle, staticPageMeta, truncateDescription, translateMeta } from "@/core/lib/seo-meta"
 
 export const meta: MetaFunction = ({ matches }) => {
     const lang = resolveMetaLanguage(matches)
     return staticPageMeta({
         title: siteTitle(lang, "legal.terms.title"),
-        description: truncateDescription(translate(lang, "legal.terms.p1")),
+        description: truncateDescription(translateMeta(lang, "legal.terms.p1")),
         path: "/terms",
     })
 }

frontend/app/pages/compare/index.tsx

@@ -8,13 +8,12 @@ import { TimeIntervalSelector } from "@/ui/components/TimeIntervalSelector"
 import { SelectedServersTags } from "@/pages/compare/components/SelectedServersTags"
 import { useCompareRecords } from "@/pages/compare/hooks/useCompareRecords"
 import type { MetaFunction } from "react-router"
-import { translate } from "@/core/lib/i18n"
-import { resolveMetaLanguage, siteTitle, staticPageMeta } from "@/core/lib/seo-meta"
+import { resolveMetaLanguage, siteTitle, staticPageMeta, translateMeta } from "@/core/lib/seo-meta"
 
 export const meta: MetaFunction = ({ matches }) => {
     const lang = resolveMetaLanguage(matches)
     const title = siteTitle(lang, "comparison.title")
-    const description = translate(lang, "comparison.noSelectionDesc")
+    const description = translateMeta(lang, "comparison.noSelectionDesc")
     return staticPageMeta({ title, description, path: "/compare" })
 }
 

frontend/app/pages/home/index.tsx

@@ -21,17 +21,16 @@ import { FaqSection } from "@/pages/home/components/FaqSection"
 import { Pagination } from "@/ui/components/pagination"
 
 import type { LoaderFunctionArgs, MetaFunction } from "react-router"
-import { translate } from "@/core/lib/i18n"
-import { resolveMetaLanguage, staticPageMeta } from "@/core/lib/seo-meta"
+import { resolveMetaLanguage, staticPageMeta, translateMeta } from "@/core/lib/seo-meta"
 
 // La home est la seule page avec des variantes filtrées/paginées (?tab=&page=...) :
 // le canonical pointe toujours vers l'URL clean pour consolider l'indexation.
 // Jeu de tags complet : le meta() feuille remplace celui du root.
 export const meta: MetaFunction = ({ matches }) => {
     const lang = resolveMetaLanguage(matches)
     return staticPageMeta({
-        title: translate(lang, "seo.homeTitle"),
-        description: translate(lang, "seo.homeDescription"),
+        title: translateMeta(lang, "seo.homeTitle"),
+        description: translateMeta(lang, "seo.homeDescription"),
         path: "/",
     })
 }

frontend/app/pages/server-detail/index.tsx

@@ -3,7 +3,7 @@ import { Link, useLoaderData, useRouteError } from "react-router"
 import type { LoaderFunctionArgs, MetaFunction } from "react-router"
 import { fetchServer, getServerIconUrl } from "@/core/lib/api"
 import { APP_URL } from "@/core/lib/config"
-import { translate, type Language } from "@/core/lib/i18n"
+import { translateMeta, type Language } from "@/core/lib/seo-meta"
 
 const PlayerChart = lazy(() =>
     import("@/pages/server-detail/components/PlayerChart").then((m) => ({
@@ -84,12 +84,13 @@ export async function clientLoader({ params }: LoaderFunctionArgs) {
 export const meta: MetaFunction<typeof loader> = (args) => {
     const { loaderData: data } = args
 
-    // Langue résolue par le loader root (cookie ou Accept-Language)
-    const rootData = args.matches?.find((m) => m.id === "root")?.data as
+    // Langue résolue par le loader root (cookie ou Accept-Language).
+    // Les matches React Router exposent les données sous `loaderData` (pas `data`).
+    const rootData = args.matches?.find((m) => m.id === "root")?.loaderData as
         | { serverLanguage?: Language }
         | undefined
     const lang: Language = rootData?.serverLanguage ?? "fr"
-    const L = (path: string, vars?: Record<string, string>) => translate(lang, path, vars)
+    const L = (path: string, vars?: Record<string, string>) => translateMeta(lang, path, vars)
 
     if (!data || !data.initialServer) {
         return [

frontend/app/root.tsx

@@ -24,7 +24,8 @@ import { BedrockLogoSprite } from "@/ui/components/BedrockLogo";
 import { LabyLogoSprite } from "@/ui/components/LabyLogo";
 import { APP_URL } from "@/core/lib/config";
 import { parseLanguageCookie, resolveLanguageFromHeader } from "@/core/lib/accept-language";
-import { translate, type Language } from "@/core/lib/i18n";
+import { type Language } from "@/core/lib/i18n";
+import { translateMeta } from "@/core/lib/seo-meta";
 
 const PUBLISHABLE_KEY = import.meta.env.VITE_CLERK_PUBLISHABLE_KEY;
 
@@ -63,7 +64,7 @@ export function shouldRevalidate() {
 
 export function meta({ data }: { data?: { serverLanguage?: Language } }) {
   const lang = data?.serverLanguage ?? "fr"
-  const L = (path: string) => translate(lang, path)
+  const L = (path: string) => translateMeta(lang, path)
 
   return [
     { title: L("seo.homeTitle") },
@@ -135,7 +136,7 @@ export function Layout({ children }: { children: React.ReactNode }) {
                   "@id": `${APP_URL}/#website`,
                   "name": "Minecraft-Stats",
                   "url": APP_URL,
-                  "description": translate(lang, "seo.homeDescription"),
+                  "description": translateMeta(lang, "seo.homeDescription"),
                   "publisher": { "@id": `${APP_URL}/#organization` },
                   "potentialAction": {
                     "@type": "SearchAction",