Fix onboarding language copy and configuration recovery

CHANGELOG.md

@@ -9,7 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Onboarding learning goals now name the selected language in all ten interface languages, with natural wording and a safe display fallback for unrecognized language codes.
 - Public signup controls now reflect `ALLOW_REGISTRATION`: closed registration shows a localized invite-only message and Login action, while invitation links retain access to the registration form. The existing flag is exposed through `/api/config`.
+- Configuration loading can retry after temporary network or invalid JSON failures, so registration and billing controls recover on subsequent navigation without requiring a full page reload.
+- Blocked email-domain registration uses the current HTTP 422 status constant, avoiding the deprecated Starlette alias while preserving the response code and message.
+- Flashcard concurrent-deletion tests detach the deleted object before promotion, avoiding SQLAlchemy identity-map collisions when SQLite reuses its ID while preserving the simulated deletion scenario.
 
 ## [1.9.15] - 2026-09-22
 

backend/app/routers/auth.py

@@ -79,7 +79,7 @@ async def register(
         email_domain = data.email.split("@")[-1].lower()
         if email_domain in [d.lower() for d in settings.BLOCKED_EMAIL_DOMAINS]:
             raise HTTPException(
-                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
                 detail="Email domain not allowed",
             )
 

backend/tests/test_flashcards.py

@@ -795,6 +795,8 @@ async def delete_then_promote(db, existing):
             .execution_options(synchronize_session=False)
         )
         await db.commit()
+        # Keep the stale reference without an identity-map collision if SQLite reuses its ID.
+        db.expunge(existing)
         return await respond(db, existing)
 
     async def lookup(**kwargs):

frontend/src/app/(auth)/onboarding/page.tsx

@@ -12,7 +12,10 @@ import { useAuthStore, isSubscribed, isFreemiumTrialActive } from '@/store/auth'
 import { useConfigStore } from '@/store/config'
 import { useLanguageStore } from '@/store/language'
 import TargetLanguageSelector from '@/components/TargetLanguageSelector'
-import { DEFAULT_TARGET_LANGUAGE } from '@/lib/target-languages'
+import {
+  DEFAULT_TARGET_LANGUAGE,
+  getLanguageByCode,
+} from '@/lib/target-languages'
 
 const LEARNING_GOALS = [
   'travel',
@@ -34,6 +37,7 @@ function getSelectedPlan(plan: string | null): BillingInterval | null {
 export default function OnboardingPage() {
   const t = useTranslations('onboarding')
   const tCommon = useTranslations('common')
+  const tLang = useTranslations('targetLanguages')
   const router = useRouter()
   const searchParams = useSearchParams()
   const setUser = useAuthStore((s) => s.setUser)
@@ -64,6 +68,11 @@ export default function OnboardingPage() {
     useState<BillingInterval | null>(null)
   const [checkoutError, setCheckoutError] = useState('')
 
+  const targetLanguageName = tLang(
+    getLanguageByCode(targetLanguage)?.iso639 ??
+      DEFAULT_TARGET_LANGUAGE.split('-')[0]
+  )
+
   useEffect(() => {
     loadConfig()
     fetchLanguages().then(() => {
@@ -266,7 +275,7 @@ export default function OnboardingPage() {
           {step === 2 && (
             <div className="space-y-5">
               <p className="text-fl-fg font-mono text-sm">
-                {t('goals.subtitle')}
+                {t('goals.subtitle', { language: targetLanguageName })}
               </p>
               <div className="grid grid-cols-2 gap-2">
                 {LEARNING_GOALS.map((goal) => {

frontend/src/store/config.ts

@@ -64,8 +64,7 @@ export const useConfigStore = create<ConfigStore>((set, get) => ({
         loaded: true,
       })
     } catch {
-      // Non-fatal: keep conservative presentation defaults
-      set({ loaded: true })
+      // Non-fatal: keep conservative defaults and allow the next load to retry.
     }
   },
 }))

frontend/tests/app/onboarding-goals-subtitle.test.tsx

@@ -0,0 +1,181 @@
+import React from 'react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { NextIntlClientProvider } from 'next-intl'
+import { TARGET_LANGUAGE_CATALOG } from '@/lib/target-languages'
+import { useAuthStore } from '@/store/auth'
+import { useConfigStore } from '@/store/config'
+import { useLanguageStore } from '@/store/language'
+import de from '../../../messages/de.json'
+import en from '../../../messages/en.json'
+import es from '../../../messages/es.json'
+import fr from '../../../messages/fr.json'
+import itMessages from '../../../messages/it.json'
+import nl from '../../../messages/nl.json'
+import pl from '../../../messages/pl.json'
+import pt from '../../../messages/pt.json'
+import ro from '../../../messages/ro.json'
+import ru from '../../../messages/ru.json'
+
+const { searchParams, apiFetch } = vi.hoisted(() => ({
+  searchParams: new URLSearchParams(),
+  apiFetch: vi.fn(),
+}))
+
+vi.mock('next/navigation', () => ({
+  useRouter: () => ({ push: vi.fn() }),
+  useSearchParams: () => searchParams,
+}))
+
+vi.mock('@/lib/api', () => ({ apiFetch }))
+
+import OnboardingPage from '@/app/(auth)/onboarding/page'
+
+const catalogs = { de, en, es, fr, it: itMessages, nl, pl, pt, ro, ru }
+type Locale = keyof typeof catalogs
+
+const spanishSubtitles: Record<Locale, string> = {
+  de: 'Sprache: Spanisch. Wofür möchtest du sie nutzen? Wähle alle zutreffenden Ziele aus.',
+  en: 'Language: Spanish. What do you want to use it for? Select all that apply.',
+  es: 'Idioma: español. ¿Para qué quieres utilizarlo? Selecciona todos los objetivos que correspondan.',
+  fr: "Langue : espagnol. Dans quel but souhaitez-vous l'utiliser ? Sélectionnez tous les objectifs qui vous correspondent.",
+  it: 'Lingua: spagnolo. Per cosa vuoi usarla? Seleziona tutti gli obiettivi che fanno al caso tuo.',
+  nl: 'Taal: Spaans. Waarvoor wil je deze taal gebruiken? Selecteer alle doelen die van toepassing zijn.',
+  pl: 'Język: hiszpański. Do czego chcesz go używać? Zaznacz wszystkie cele, które Ci odpowiadają.',
+  pt: 'Idioma: espanhol. Para que você quer usá-lo? Selecione todos os objetivos que se aplicam.',
+  ro: 'Limbă: spaniolă. Pentru ce vrei să o folosești? Selectează toate obiectivele care ți se potrivesc.',
+  ru: 'Язык: испанский. Для чего ты хочешь его использовать? Выбери все подходящие цели.',
+}
+
+const onIntlError = vi.fn()
+const englishSubtitle =
+  'Language: English. What do you want to use it for? Select all that apply.'
+
+function languageResponse(
+  codes = TARGET_LANGUAGE_CATALOG.map((language) => language.code)
+) {
+  return new Response(
+    JSON.stringify({ languages: [], all_supported_languages: codes })
+  )
+}
+
+function renderOnboarding(locale: Locale = 'en') {
+  return render(
+    <NextIntlClientProvider
+      locale={locale}
+      messages={catalogs[locale]}
+      timeZone="UTC"
+      onError={onIntlError}
+    >
+      <OnboardingPage />
+    </NextIntlClientProvider>
+  )
+}
+
+beforeEach(() => {
+  for (const key of Array.from(searchParams.keys())) searchParams.delete(key)
+  onIntlError.mockReset()
+  apiFetch.mockReset()
+  apiFetch.mockImplementation(async () => languageResponse())
+  useAuthStore.setState({ ...useAuthStore.getInitialState() }, true)
+  useConfigStore.setState(
+    { ...useConfigStore.getInitialState(), loaded: true },
+    true
+  )
+  useLanguageStore.setState({ ...useLanguageStore.getInitialState() }, true)
+})
+
+afterEach(() => {
+  cleanup()
+  expect(onIntlError).not.toHaveBeenCalled()
+})
+
+describe('onboarding goals subtitle', () => {
+  it.each(Object.keys(catalogs) as Locale[])(
+    'names the selected language with natural wording in the %s UI',
+    async (locale) => {
+      const messages = catalogs[locale]
+      renderOnboarding(locale)
+
+      fireEvent.click(
+        await screen.findByRole('button', {
+          name: new RegExp(messages.targetLanguages['es-ES']),
+        })
+      )
+      fireEvent.click(
+        screen.getByRole('button', { name: messages.common.next })
+      )
+
+      expect(screen.getByText(spanishSubtitles[locale])).toBeInTheDocument()
+    }
+  )
+
+  it.each([
+    [null, 'English'],
+    ['en-GB', 'English'],
+    ['en-US', 'English'],
+    ['de-DE', 'German'],
+    ['fr-FR', 'French'],
+    ['it-IT', 'Italian'],
+    ['pt-PT', 'Portuguese'],
+    ['ja-JP', 'Japanese'],
+    ['ko-KR', 'Korean'],
+    ['zh-CN', 'Chinese'],
+  ])(
+    'uses the language-level name for query language=%s',
+    async (code, name) => {
+      if (code) searchParams.set('language', code)
+      renderOnboarding()
+      await screen.findByRole('button', { name: /Spanish/ })
+      fireEvent.click(screen.getByRole('button', { name: 'Next' }))
+
+      expect(
+        screen.getByText(
+          `Language: ${name}. What do you want to use it for? Select all that apply.`
+        )
+      ).toBeInTheDocument()
+    }
+  )
+
+  it.each(['', 'unknown-language'])(
+    'safely displays the default for language=%s while languages load',
+    async (code) => {
+      searchParams.set('language', code)
+      let resolveLanguages!: (response: Response) => void
+      apiFetch.mockReturnValueOnce(
+        new Promise<Response>((resolve) => {
+          resolveLanguages = resolve
+        })
+      )
+      renderOnboarding()
+      fireEvent.click(screen.getByRole('button', { name: 'Next' }))
+
+      expect(screen.getByText(englishSubtitle)).toBeInTheDocument()
+
+      await act(async () => resolveLanguages(languageResponse(['fr-FR'])))
+
+      expect(
+        screen.getByText(
+          'Language: French. What do you want to use it for? Select all that apply.'
+        )
+      ).toBeInTheDocument()
+    }
+  )
+
+  it.each(['HTTP', 'network'])(
+    'safely displays the default for an invalid query after a %s failure',
+    async (failure) => {
+      searchParams.set('language', 'unknown-language')
+      if (failure === 'HTTP') {
+        apiFetch.mockResolvedValueOnce(new Response('', { status: 503 }))
+      } else {
+        apiFetch.mockRejectedValueOnce(new Error('offline'))
+      }
+      renderOnboarding()
+      await screen.findByText(en.onboarding.saveFailed)
+      fireEvent.click(screen.getByRole('button', { name: 'Next' }))
+
+      expect(screen.getByText(englishSubtitle)).toBeInTheDocument()
+    }
+  )
+})

frontend/tests/store/config.test.ts

@@ -96,17 +96,46 @@ describe('useConfigStore', () => {
     expect(fetch).toHaveBeenCalledTimes(1)
   })
 
-  it('keeps defaults when fetch fails', async () => {
+  it('keeps defaults and allows retry when fetch fails', async () => {
     vi.mocked(fetch).mockRejectedValueOnce(new Error('network error'))
 
     await useConfigStore.getState().load()
 
     expect(useConfigStore.getState().allowRegistration).toBe(false)
     expect(useConfigStore.getState().stripeEnabled).toBe(false)
     expect(useConfigStore.getState().ttsProvider).toBe('local')
-    expect(useConfigStore.getState().loaded).toBe(true)
+    expect(useConfigStore.getState().loaded).toBe(false)
   })
 
+  it.each(['network error', 'invalid JSON'])(
+    'recovers registration and billing configuration after %s',
+    async (failure) => {
+      if (failure === 'network error') {
+        vi.mocked(fetch).mockRejectedValueOnce(new Error('offline'))
+      } else {
+        vi.mocked(fetch).mockResolvedValueOnce(new Response('invalid JSON'))
+      }
+      vi.mocked(fetch).mockResolvedValueOnce(
+        new Response(
+          JSON.stringify({ allow_registration: true, stripe_enabled: true })
+        )
+      )
+
+      await useConfigStore.getState().load()
+
+      expect(useConfigStore.getState().allowRegistration).toBe(false)
+      expect(useConfigStore.getState().stripeEnabled).toBe(false)
+      expect(useConfigStore.getState().loaded).toBe(false)
+
+      await useConfigStore.getState().load()
+
+      expect(fetch).toHaveBeenCalledTimes(2)
+      expect(useConfigStore.getState().allowRegistration).toBe(true)
+      expect(useConfigStore.getState().stripeEnabled).toBe(true)
+      expect(useConfigStore.getState().loaded).toBe(true)
+    }
+  )
+
   it('does not mark loaded when response is not ok (allows retry)', async () => {
     vi.mocked(fetch).mockResolvedValueOnce(
       new Response('error', { status: 500 })

messages/de.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Einstellungen konnten nicht gespeichert werden",
     "goals": {
       "title": "Deine Lernziele",
-      "subtitle": "Wozu möchtest du Englisch nutzen? Wähle alles Zutreffende.",
+      "subtitle": "Sprache: {language}. Wofür möchtest du sie nutzen? Wähle alle zutreffenden Ziele aus.",
       "skip": "Überspringen",
       "travel": "Reisen & Tourismus",
       "work": "Beruf & Karriere",

messages/en.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Failed to save preferences",
     "goals": {
       "title": "Your Learning Goals",
-      "subtitle": "What do you want to use English for? Select all that apply.",
+      "subtitle": "Language: {language}. What do you want to use it for? Select all that apply.",
       "skip": "Skip",
       "travel": "Travel & Tourism",
       "work": "Work & Professional",

messages/es.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Error al guardar las preferencias",
     "goals": {
       "title": "Tus objetivos de aprendizaje",
-      "subtitle": "¿Para qué quieres usar el inglés? Selecciona todos los que apliquen.",
+      "subtitle": "Idioma: {language}. ¿Para qué quieres utilizarlo? Selecciona todos los objetivos que correspondan.",
       "skip": "Omitir",
       "travel": "Viajes y turismo",
       "work": "Trabajo y carrera",

messages/fr.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Échec de l'enregistrement des préférences",
     "goals": {
       "title": "Vos objectifs d'apprentissage",
-      "subtitle": "Pour quoi voulez-vous utiliser l'anglais ? Sélectionnez tout ce qui s'applique.",
+      "subtitle": "Langue : {language}. Dans quel but souhaitez-vous l'utiliser ? Sélectionnez tous les objectifs qui vous correspondent.",
       "skip": "Passer",
       "travel": "Voyages et tourisme",
       "work": "Travail et carrière",

messages/it.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Impossibile salvare le preferenze",
     "goals": {
       "title": "I tuoi obiettivi",
-      "subtitle": "Per cosa vuoi usare l'inglese? Seleziona tutto ciò che si applica.",
+      "subtitle": "Lingua: {language}. Per cosa vuoi usarla? Seleziona tutti gli obiettivi che fanno al caso tuo.",
       "skip": "Salta",
       "travel": "Viaggi e turismo",
       "work": "Lavoro e carriera",

messages/nl.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Opslaan van voorkeuren mislukt",
     "goals": {
       "title": "Jouw leerdoelen",
-      "subtitle": "Waarvoor wil je Engels gebruiken? Selecteer alles wat van toepassing is.",
+      "subtitle": "Taal: {language}. Waarvoor wil je deze taal gebruiken? Selecteer alle doelen die van toepassing zijn.",
       "skip": "Overslaan",
       "travel": "Reizen en toerisme",
       "work": "Werk en carrière",

messages/pl.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Nie udało się zapisać preferencji",
     "goals": {
       "title": "Twoje cele nauki",
-      "subtitle": "Do czego chcesz używać angielskiego? Zaznacz wszystkie, które dotyczą Ciebie.",
+      "subtitle": "Język: {language}. Do czego chcesz go używać? Zaznacz wszystkie cele, które Ci odpowiadają.",
       "skip": "Pominąć",
       "travel": "Podróże i turystyka",
       "work": "Praca i kariera",

messages/pt.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Falha ao salvar as preferências",
     "goals": {
       "title": "Seus objetivos de aprendizado",
-      "subtitle": "Para quê você quer usar o inglês? Selecione tudo que se aplica.",
+      "subtitle": "Idioma: {language}. Para que você quer usá-lo? Selecione todos os objetivos que se aplicam.",
       "skip": "Pular",
       "travel": "Viagens e turismo",
       "work": "Trabalho e carreira",

messages/ro.json

@@ -1295,7 +1295,7 @@
     "saveFailed": "Salvarea preferințelor a eșuat",
     "goals": {
       "title": "Obiectivele tale de învățare",
-      "subtitle": "Pentru ce vrei să folosești engleza? Selectează tot ce ți se potrivește.",
+      "subtitle": "Limbă: {language}. Pentru ce vrei să o folosești? Selectează toate obiectivele care ți se potrivesc.",
       "skip": "Sari",
       "travel": "Călătorii și turism",
       "work": "Muncă și carieră",