ranuts · chaxus · Aug 23, 2026 · Aug 23, 2026
diff --git a/bin/build-pages.mjs b/bin/build-pages.mjs
@@ -832,7 +832,9 @@ ${langOptions}
           <div class="recent reveal d5">
             <span data-recent-slot data-recent-label="${e(data.recent.label)}" hidden></span>
             <span class="recent-note">${e(data.recent.note)}</span>
-            <a class="recent-all" href="/history">${e(data.recent.all)}</a>
+            <a class="recent-all" href="${locale === DEFAULT_LOCALE ? '/history' : `/history?locale=${locale}`}"
+              >${e(data.recent.all)}</a
+            >
           </div>
           <div class="trust reveal d5">${trust}</div>
         </div>

diff --git a/docs/explorations/2026-08-23-seven-languages-audit.md b/docs/explorations/2026-08-23-seven-languages-audit.md
@@ -63,6 +63,31 @@ landing.css。白色主题下看不出来，暗色下就是页面四周一圈底
 
 顺带补上落地页 `WebApplication` 节点缺的 `inLanguage`（首页和文档页早就有）。
 
+## 9. 选了语言，走到 app 页面就丢（已修）
+
+用户报的：首页切到日语，跳去其它页面还是英文。复现路径正是这样：
+
+    /ja/ 是日语 → 点「保存したドキュメント」→ /history → 英文
+
+两个独立的原因，各修各的：
+
+1. **首页指向 app 的链接没带语言**。站点是七个静态目录 **加上一个 app**（`/editor`
+   与 `/history`），app 不在任何语言目录下面。`/ja/` 上的 `/history` 链接因此是裸的，
+   app 只能按浏览器语言猜。生成器现在输出 `/history?locale=ja`；
+   `history-recent.js` 拼的「继续编辑」链接同样带上（它读 `<html lang>`）；
+   `/history` 自己的行链接与「返回首页」也带（`withLocale` / `localeHomePath`，
+   新导出在 `packages/shared/src/i18n.ts`）。
+2. **选择从来没被记住**。`lang-switch.js` 过去只是导航——语言只存在于用户当前站着的
+   那条路径里。现在它在跳转前写 `locale` cookie（一年，`samesite=lax`）。app 的语言解析链
+   第二位就是 cookie，所以之后直接打开 `/editor` 或 `/history` 也跟随。
+
+两条缺一不可：链接带参数让**第一次点击**就对（新浏览器、别人分享的链接都算），
+cookie 让**之后的直接访问**也对。
+
+实测整条路径（浏览器语言 en-US）：落地英文首页 → 菜单选日语 → 保存的文档 → 裸
+`/editor` → 裸 `/history` → 落地页，六步全是 `lang=ja`。反向验证：去掉 cookie 那段，
+E2E 的第 4/5 步立刻回落英文。
+
 ## 复查过但没有问题的
 
 - **SEO 覆盖**：7 种语言 × 21 页齐全；hreflang 是完整的七语言互指 + x-default；

diff --git a/index.html b/index.html
@@ -244,7 +244,9 @@ <h1 class="reveal d2">Open Word, Excel &amp; PowerPoint files, <span class="acce
           <div class="recent reveal d5">
             <span data-recent-slot data-recent-label="Continue editing" hidden></span>
             <span class="recent-note">Close the tab by accident and nothing is lost: your edits are saved into this browser as you work. Saved copies stay for 7 days and are then deleted automatically — or delete them yourself at any time.</span>
-            <a class="recent-all" href="/history">Saved documents</a>
+            <a class="recent-all" href="/history"
+              >Saved documents</a
+            >
           </div>
           <div class="trust reveal d5"><span>0 bytes uploaded</span><span>no account</span><span>works offline</span><span>.docx .xlsx .pptx .csv</span></div>
         </div>

diff --git a/lib/history-page.ts b/lib/history-page.ts
@@ -18,7 +18,7 @@ import 'ranui/message';
 import { Div, View } from 'ranui/builder';
 import '../styles/history.css';
 import { saveFileToDisk } from 'ranuts/utils';
-import { applyDocumentLanguage, t } from '@ranuts/shared/i18n';
+import { applyDocumentLanguage, getLanguage, localeHomePath, t, withLocale } from '@ranuts/shared/i18n';
 import { getDocumentMimeType } from '@ranuts/shared/document-utils';
 import { formatRelativeTime } from './history/recovery';
 import { clearAllHistory, deleteDoc, getLatestSnapshot, historyUsage, listDocs, pruneExpired } from './history/store';
@@ -138,7 +138,9 @@ function buildRow(doc: HistoryDoc, refresh: () => void): HTMLElement {
     .children(
       View('a')
         .class('history-row-title history-open')
-        .attr('href', `/editor?saved=${encodeURIComponent(doc.id)}`)
+        // Carry the language: this page knows which one it is in, and the
+        // editor should not have to guess it again from the browser.
+        .attr('href', withLocale(`/editor?saved=${encodeURIComponent(doc.id)}`, getLanguage()))
         .text(doc.title)
         .build(),
       ...(hasUnsavedWork(doc)
@@ -325,7 +327,8 @@ async function render(): Promise<void> {
               button(
                 t('historyBack'),
                 () => {
-                  window.location.href = '/';
+                  // Back to the homepage the reader came from, not to English.
+                  window.location.href = localeHomePath(getLanguage());
                 },
                 { type: 'text', class: 'history-back' },
               ),

diff --git a/packages/shared/src/i18n.ts b/packages/shared/src/i18n.ts
@@ -71,6 +71,25 @@ export const RTL_LANGUAGES: readonly Language[] = [];
 
 export const isRtlLanguage = (lang: Language): boolean => RTL_LANGUAGES.includes(lang);
 
+/**
+ * Where a language's homepage lives. English is the site root; every other
+ * language is a directory under it. Mirrors LOCALES in bin/build-pages.mjs,
+ * which generates those pages -- the app needs it to send a reader back to the
+ * homepage they came from rather than to the English one.
+ */
+export const localeHomePath = (lang: Language): string => (lang === LanguageCode.EN ? '/' : `/${lang}/`);
+
+/**
+ * Add `?locale=` to an app URL when the language is not the default. The app
+ * resolves its language from the URL first, so a link that carries it works
+ * even for a reader who has never chosen one explicitly (a shared link, a new
+ * browser) -- the cookie only covers people who used the switch.
+ */
+export const withLocale = (url: string, lang: Language): string => {
+  if (lang === LanguageCode.EN) return url;
+  return `${url}${url.includes('?') ? '&' : '?'}locale=${lang}`;
+};
+
 /**
  * Editor (OnlyOffice) UI locales shipped by the vendored web-apps build --
  * `public/web-apps/apps/<app>/main/locale/<code>.json`. The site shell has

diff --git a/public/history-recent.js b/public/history-recent.js
@@ -78,7 +78,11 @@
       // not depend on a script having run.
       var resume = document.createElement('a');
       resume.className = 'recent-resume';
-      resume.href = '/editor?saved=' + encodeURIComponent(doc.id) + suffix;
+      // Keep the page's language on the way into the editor: this script runs
+      // on /ja/, /pt/ and the rest, and the editor resolves ?locale= first.
+      var pageLang = document.documentElement.lang || 'en';
+      var localeParam = pageLang && pageLang !== 'en' ? '&locale=' + encodeURIComponent(pageLang) : '';
+      resume.href = '/editor?saved=' + encodeURIComponent(doc.id) + localeParam + suffix;
       resume.textContent = (slot.getAttribute('data-recent-label') || 'Continue') + ' ' + doc.title;
 
       slot.appendChild(resume);

diff --git a/public/lang-switch.js b/public/lang-switch.js
@@ -16,6 +16,18 @@ document.addEventListener('DOMContentLoaded', function () {
     if (!value) return;
     var option = select.querySelector('r-option[value="' + value + '"]');
     var href = option && option.getAttribute('data-href');
-    if (href && href !== location.pathname) location.href = href;
+    if (!href || href === location.pathname) return;
+    // Remember the choice before navigating. The static pages carry their
+    // language in the URL, but /editor and /history are one app that reads
+    // its language from (in order) ?locale=, this cookie, localStorage and
+    // the browser. Without the cookie, picking 日本語 on the homepage and
+    // then opening the saved-documents page landed the reader back in
+    // English -- the choice existed only as the path they were standing on.
+    try {
+      document.cookie = 'locale=' + encodeURIComponent(value) + ';path=/;max-age=31536000;samesite=lax';
+    } catch (e) {
+      /* cookies disabled: the URL still carries the language */
+    }
+    location.href = href;
   });
 });
diff --git a/test/e2e/language-menu.spec.ts b/test/e2e/language-menu.spec.ts
@@ -92,6 +92,36 @@ test.describe('language menu', () => {
   });
 });
 
+test.describe('a chosen language follows the reader', () => {
+  /**
+   * The site is seven directories of static pages plus one app (/editor and
+   * /history) that resolves its language from ?locale=, then a cookie, then
+   * localStorage, then the browser. Picking a language on a static page used
+   * to be nothing but a navigation: the choice lived in the path, and the
+   * moment a reader stepped off it -- "saved documents" from the Japanese
+   * homepage -- they were back in English.
+   */
+  test('picking a language on a static page reaches the app pages too', async ({ page }) => {
+    await page.goto('/');
+    // Choose 日本語 through the menu, the way a reader does.
+    await page.locator('r-select.lang-select').first().click();
+    await page.locator('r-dropdown-item[value="ja"]').first().click();
+    await page.waitForURL('**/ja/');
+    expect(await page.evaluate(() => document.documentElement.lang)).toBe('ja');
+
+    // The link into the app carries it...
+    const historyHref = await page.locator('a.recent-all').getAttribute('href');
+    expect(historyHref).toContain('locale=ja');
+
+    // ...and so does the app itself, even at a bare URL, because the choice
+    // was remembered rather than only navigated to.
+    await page.goto('/history');
+    await expect.poll(() => page.evaluate(() => document.documentElement.lang)).toBe('ja');
+    await page.goto('/editor?new=docx');
+    await expect.poll(() => page.evaluate(() => document.documentElement.lang)).toBe('ja');
+  });
+});
+
 test.describe('page chrome', () => {
   /**
    * The browser's default 8px body margin. landing.css always cleared it;

diff --git a/test/unit/landing-pages.test.ts b/test/unit/landing-pages.test.ts
@@ -166,6 +166,21 @@ describe('landing pages', () => {
         expect(alternates.sort(), `${route} og:locale:alternate`).toEqual(expected.sort());
       });
 
+      /**
+       * /editor and /history are one app serving every language, so a link from
+       * a translated page into them has to say which one. Picking 日本語 on the
+       * homepage and then opening the saved-documents page used to land the
+       * reader back in English: the choice existed only as the path they were
+       * standing on, and /history is not under it.
+       */
+      it('carries the language on every link into the app', () => {
+        const appLinks = [...html.matchAll(/(?:href|data-open-local)="(\/(?:editor|history)[^"]*)"/g)].map((m) => m[1]);
+        for (const link of appLinks) {
+          const carries = link.includes(`locale=${locale}`);
+          expect(locale === 'en' ? !link.includes('locale=') : carries, `${route}: ${link}`).toBe(true);
+        }
+      });
+
       it('offers every translation it has in the language switch', () => {
         for (const other of Object.keys(LOCALES)) {
           const target = routeIn(other, enRoute);