fix(i18n): apply each user's language and keep the picker in step

CHANGELOG.md

@@ -7,6 +7,20 @@ ones are marked like "v1.0.0-fork".
 
 ## [Unreleased]
 
+### Fixed
+
+* **The interface language setting had no effect on multi-user installs.** The
+  language was read before the signed-in user was known, so everyone got the
+  default. It now applies to every signed-in page, and the preferences page
+  reloads to show it as soon as it is saved.
+
+* **The language picker fell out of step with the page.** On multi-user installs
+  `?filterlang=` links never changed the current language, and creating a
+  language, opening a text or reviewing a language left the picker on the old
+  one. All of these now update it. Remembered sort orders had the same fault
+  and now persist per user, and none of these values reach the shared defaults
+  any more.
+
 ## [3.8.1-fork] - 2026-11-04
 
 ### Changed in 3.8.1-fork

cypress.config.ts

@@ -3,6 +3,21 @@ import { defineConfig } from 'cypress';
 export default defineConfig({
   e2e: {
     baseUrl: 'http://localhost:8000',
+    setupNodeEvents(on) {
+      on('task', {
+        // In Node, because cy.request() fails the test on a refused connection.
+        ankiConnectVersion(url: string): Promise<number | null> {
+          return fetch(url, {
+            method: 'POST',
+            body: JSON.stringify({ action: 'version', version: 6 }),
+            signal: AbortSignal.timeout(3000)
+          })
+            .then((response) => response.json())
+            .then((body: { result?: number }) => body.result ?? null)
+            .catch(() => null);
+        }
+      });
+    },
     supportFile: 'cypress/support/e2e.ts',
     specPattern: 'cypress/e2e/**/*.cy.ts',
     viewportWidth: 1280,

cypress/e2e/24-anki-live.cy.ts

@@ -51,12 +51,9 @@ describe('Sync reviews with a real Anki', () => {
   const extraDecks: string[] = [];
 
   before(() => {
-    cy.request({ method: 'POST', url: anki, body: { action: 'version', version: 6 }, failOnStatusCode: false, timeout: 3000 })
-      .then((response) => {
-        ankiUp = response.status === 200 && (response.body as { result?: number }).result === 6;
-      }, () => {
-        ankiUp = false;
-      });
+    cy.task<number | null>('ankiConnectVersion', anki).then((version) => {
+      ankiUp = version === 6;
+    });
   });
 
   beforeEach(function () {

docs-src/changelog.md

@@ -12,6 +12,20 @@ ones are marked like "v1.0.0-fork".
 
 ## [Unreleased]
 
+### Fixed
+
+* **The interface language setting had no effect on multi-user installs.** The
+  language was read before the signed-in user was known, so everyone got the
+  default. It now applies to every signed-in page, and the preferences page
+  reloads to show it as soon as it is saved.
+
+* **The language picker fell out of step with the page.** On multi-user installs
+  `?filterlang=` links never changed the current language, and creating a
+  language, opening a text or reviewing a language left the picker on the old
+  one. All of these now update it. Remembered sort orders had the same fault
+  and now persist per user, and none of these values reach the shared defaults
+  any more.
+
 ## [3.8.1-fork] - 2026-11-04
 
 ### Changed in 3.8.1-fork

src/Modules/Language/Http/LanguageApiHandler.php

@@ -26,6 +26,7 @@
 use Lwt\Shared\Infrastructure\Http\JsonResponse;
 use Lwt\Api\V1\Response;
 use Lwt\Modules\Language\Application\LanguageFacade;
+use Lwt\Shared\Infrastructure\Language\CurrentLanguage;
 use Lwt\Shared\Infrastructure\Language\LanguagePresets;
 use Lwt\Modules\Text\Application\Services\SentenceService;
 use Lwt\Modules\Vocabulary\Application\UseCases\FindSimilarTerms;
@@ -368,6 +369,7 @@ public function formatCreate(array $data): array
 
         $id = $this->languageFacade->createFromData($data);
         if ($id > 0) {
+            CurrentLanguage::follow($id);
             return ['success' => true, 'id' => $id];
         }
 
@@ -501,7 +503,7 @@ public function formatGetDefinitions(): array
      */
     public function formatSetDefault(int $id): array
     {
-        Settings::save('currentlanguage', (string)$id);
+        Settings::savePerUser('currentlanguage', (string)$id);
         return ['success' => true];
     }
 

src/Modules/Review/Http/ReviewController.php

@@ -23,6 +23,7 @@
 use Lwt\Modules\Review\Application\ReviewFacade;
 use Lwt\Modules\Review\Infrastructure\SessionStateManager;
 use Lwt\Modules\Language\Application\LanguageFacade;
+use Lwt\Shared\Infrastructure\Language\CurrentLanguage;
 use Lwt\Shared\Infrastructure\Language\LanguagePresets;
 use Lwt\Shared\UI\Helpers\PageLayoutHelper;
 
@@ -177,6 +178,7 @@ private function renderReviewPage(): void
         // Get language settings
         $langIdFromSql = $this->reviewFacade->getLanguageIdFromReviewSql($reviewsql, $reviewParams);
         if ($langIdFromSql === null) {
+            CurrentLanguage::follow($langId ?? 0);
             PageLayoutHelper::renderPageStartNobody(__('review.page_title'), 'full-width');
             include __DIR__ . '/../Views/no_terms.php';
             PageLayoutHelper::renderPageEnd();
@@ -235,6 +237,7 @@ private function renderReviewPage(): void
             'property' => $testData['property']
         ];
 
+        CurrentLanguage::follow($langIdFromSql);
         PageLayoutHelper::renderPageStartNobody(__('review.page_title'), 'full-width');
         include __DIR__ . '/../Views/review_desktop.php';
         PageLayoutHelper::renderPageEnd();

src/Modules/Text/Http/TextReadController.php

@@ -22,6 +22,7 @@
 use Lwt\Modules\Text\Application\Services\TextDisplayService;
 use Lwt\Modules\Text\Application\Services\TextNavigationService;
 use Lwt\Shared\Infrastructure\Database\Settings;
+use Lwt\Shared\Infrastructure\Language\CurrentLanguage;
 use Lwt\Shared\UI\Helpers\PageLayoutHelper;
 use Lwt\Shared\Infrastructure\Http\RedirectResponse;
 use Lwt\Modules\Activity\Infrastructure\MySqlActivityRepository;
@@ -148,6 +149,7 @@ public function renderReadPage(int $textId): ?RedirectResponse
         // neither is rendered server-side here.
 
         Settings::savePerUser('currenttext', $textId);
+        CurrentLanguage::follow($langId);
 
         PageLayoutHelper::renderPageStartNobody(__('text.titles.read'), 'full-width');
         include self::MODULE_VIEWS . '/read_desktop.php';

src/Shared/I18n/UserLocale.php

@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * Applies the signed-in user's interface language.
+ *
+ * PHP version 8.2
+ *
+ * @category Lwt
+ * @package  Lwt\Shared\I18n
+ * @author   HugoFara <git@hugofara.net>
+ * @license  Unlicense <http://unlicense.org/>
+ * @link     https://hugofara.github.io/lwt/developer/api
+ * @since    3.8.2
+ */
+
+declare(strict_types=1);
+
+namespace Lwt\Shared\I18n;
+
+use Lwt\Shared\Infrastructure\Container\Container;
+use Lwt\Shared\Infrastructure\Database\Settings;
+
+/**
+ * Sets the translator to the language the signed-in user chose.
+ *
+ * TranslatorServiceProvider::boot() runs before the middleware restores the
+ * user, so on a multi-user install it can only see the global default. The
+ * middleware calls this once the user is known. The user's own choice also
+ * beats a leftover `lwt_lang` cookie, which only exists to serve guests.
+ *
+ * A user who never chose keeps whatever boot() settled on, so a language picked
+ * on the sign-up page lasts until they pick one in their preferences.
+ */
+final class UserLocale
+{
+    /**
+     * Apply the current user's stored interface language, if they have one.
+     *
+     * @return void
+     */
+    public static function apply(): void
+    {
+        $container = Container::getInstance();
+        if (!$container->has(Translator::class)) {
+            return;
+        }
+
+        try {
+            $locale = Settings::getOwnValue('app_language');
+        } catch (\RuntimeException $e) {
+            return;
+        }
+
+        $translator = $container->getTyped(Translator::class);
+        if ($locale !== '' && in_array($locale, $translator->getAvailableLocales(), true)) {
+            $translator->setLocale($locale);
+        }
+    }
+}

src/Shared/Infrastructure/Database/Settings.php

@@ -140,6 +140,30 @@ public static function getWithDefault(string $key): string
         return SettingDefinitions::getDefault($key) ?? '';
     }
 
+    /**
+     * Get the value the current user saved themselves.
+     *
+     * Unlike getWithDefault(), this tells "chose the default" from "never
+     * chose", which matters when a choice has to beat another source.
+     *
+     * @param string $key Setting key
+     *
+     * @return string The user's own value, '' if they have none or nobody is signed in
+     */
+    public static function getOwnValue(string $key): string
+    {
+        $userId = Globals::getCurrentUserId();
+        if ($key === '' || $userId === null) {
+            return '';
+        }
+
+        return trim((string) Connection::preparedFetchValue(
+            "SELECT StValue FROM settings WHERE StKey = ? AND StUsID = ?",
+            [$key, $userId],
+            'StValue'
+        ));
+    }
+
     /**
      * Save the setting identified by a key with a specific value.
      *

src/Shared/Infrastructure/Http/InputValidator.php

@@ -874,7 +874,7 @@ public static function getStringWithDb(
 
         if (self::has($reqKey)) {
             $value = self::getString($reqKey);
-            \Lwt\Shared\Infrastructure\Database\Settings::save($dbKey, $value);
+            \Lwt\Shared\Infrastructure\Database\Settings::savePerUser($dbKey, $value);
             return $value;
         }
 
@@ -906,7 +906,7 @@ public static function getIntWithDb(
 
         if (self::has($reqKey)) {
             $value = self::getInt($reqKey, $default);
-            \Lwt\Shared\Infrastructure\Database\Settings::save($dbKey, (string) ($value ?? $default));
+            \Lwt\Shared\Infrastructure\Database\Settings::savePerUser($dbKey, (string) ($value ?? $default));
             return $value ?? $default;
         }
 

src/Shared/Infrastructure/Language/CurrentLanguage.php

@@ -23,10 +23,10 @@
 /**
  * Resolves the language the user is currently working in.
  *
- * The `currentlanguage` setting is only written when the user actively picks a
- * language from the navbar dropdown. Two situations leave it unset or stale, and
- * both used to surface as "no language selected" even though the navbar showed
- * one:
+ * The `currentlanguage` setting is written when the user picks a language from
+ * the navbar dropdown, or when they start working in one (see follow()). Two
+ * situations can still leave it unset or stale, and both used to surface as
+ * "no language selected" even though the navbar showed one:
  *
  * - A user who has just created their first language has never fired the
  *   dropdown's `change` event. With exactly one language there is no other
@@ -39,8 +39,8 @@
  * browser falls back to displaying the first option. The display and the stored
  * state disagreed, and every server-side consumer read 0.
  *
- * This resolver is the single answer to "which language is active?". It is
- * read-only on purpose: it never writes the setting, so a plain GET has no side
+ * resolveId() is the single answer to "which language is active?". It is
+ * read-only on purpose: it never writes the setting, so resolving has no side
  * effects and the same request always resolves the same way.
  *
  * Callers that need the id to agree with what the navbar displays must use this
@@ -72,6 +72,27 @@ public static function resolveId(): int
         }
     }
 
+    /**
+     * Make a language current because the user started working in it.
+     *
+     * Keeps the navbar in step with the page: without this, opening a text in
+     * another language leaves the navbar and the next filtered page on the old
+     * one. Only the user's own languages count, since the lookup is user-scoped.
+     *
+     * @param int $languageId Language the user is now working in
+     *
+     * @return void
+     */
+    public static function follow(int $languageId): void
+    {
+        if ($languageId <= 0 || (int) Settings::get('currentlanguage') === $languageId) {
+            return;
+        }
+        if (self::exists($languageId)) {
+            Settings::savePerUser('currentlanguage', (string) $languageId);
+        }
+    }
+
     /**
      * Check whether a language ID still exists.
      *

src/Shared/Infrastructure/Routing/Middleware/AdminMiddleware.php

@@ -18,6 +18,7 @@
 namespace Lwt\Shared\Infrastructure\Routing\Middleware;
 
 use Lwt\Modules\User\Domain\User;
+use Lwt\Shared\I18n\UserLocale;
 use Lwt\Shared\Infrastructure\Globals;
 use Lwt\Modules\User\Application\UserFacade;
 use Lwt\Shared\Infrastructure\Container\Container;
@@ -90,6 +91,7 @@ public function handle(): bool
             return false;
         }
 
+        UserLocale::apply();
         return true;
     }
 

src/Shared/Infrastructure/Routing/Middleware/AuthMiddleware.php

@@ -17,6 +17,7 @@
 
 namespace Lwt\Shared\Infrastructure\Routing\Middleware;
 
+use Lwt\Shared\I18n\UserLocale;
 use Lwt\Shared\Infrastructure\Globals;
 use Lwt\Modules\User\Application\UserFacade;
 use Lwt\Shared\Infrastructure\Container\Container;
@@ -84,11 +85,13 @@ public function handle(): bool
 
         // Try session authentication
         if ($this->validateSession()) {
+            UserLocale::apply();
             return true;
         }
 
         // Try API token authentication
         if ($this->validateApiToken()) {
+            UserLocale::apply();
             return true;
         }
 

src/frontend/js/modules/user/pages/preferences_app.ts

@@ -19,6 +19,7 @@ import { ProfileApi } from '../api/profile_api';
 /** Alpine state for the preferences page. */
 export interface PreferencesAppData {
   settings: Record<string, string>;
+  loadedLocale: string | undefined;
   isLoading: boolean;
   isSaving: boolean;
   error: string;
@@ -41,6 +42,7 @@ export interface PreferencesAppData {
 export function preferencesAppData(): PreferencesAppData {
   return {
     settings: {},
+    loadedLocale: undefined,
     isLoading: false,
     isSaving: false,
     error: '',
@@ -63,6 +65,7 @@ export function preferencesAppData(): PreferencesAppData {
       }
 
       this.settings = response.data.settings;
+      this.loadedLocale = this.settings.app_language;
     },
 
     async save(): Promise<void> {
@@ -81,6 +84,12 @@ export function preferencesAppData(): PreferencesAppData {
         return;
       }
 
+      if (this.settings.app_language !== this.loadedLocale) {
+        // The page is already rendered in the old language.
+        window.location.reload();
+        return;
+      }
+
       this.success = t('user.flash.preferences_saved');
     },