fix(i18n): native plural rules for plugin packs in main, eager main init (#35403)

- Plugin pack i18next resource IDs become BCP-47 private-use tags on the
  pack's base locale (ru-RU-x-orcapk-...), so Intl and i18next pick the
  pack's plural rules natively in main and renderer. Drops the renderer
  pluralResolver.getRule patch; pack registration is shared. Persisted
  uiLanguage and pack ids keep the plugin: form.
- returnEmptyString: false in both instances; main no longer returns the
  raw uninterpolated fallback for an empty translation.
- Main i18n initializes at module load (synchronous with in-memory
  resources), removing the initialized flag and interpolateFallback.

Co-authored-by: OrcaWin <293788423+OrcaWin@users.noreply.github.com>

src/main/i18n/main-i18n-lazy-locale.test.ts

@@ -18,19 +18,12 @@ import {
   UI_LANGUAGE_RUSSIAN,
   UI_LANGUAGE_SPANISH
 } from '../../shared/ui-language'
-import {
-  ensureMainI18n,
-  mainI18n,
-  setMainPluginLanguagePacks,
-  setMainUiLanguage,
-  translateMain
-} from './main-i18n'
+import { mainI18n, setMainPluginLanguagePacks, setMainUiLanguage, translateMain } from './main-i18n'
 import { pluginLanguageResourceId } from '../../shared/plugins/plugin-language-pack-artifact'
 
 describe('main-i18n lazy locale loading', () => {
   afterEach(() => vi.restoreAllMocks())
   beforeEach(async () => {
-    await ensureMainI18n()
     setMainPluginLanguagePacks([])
     await setMainUiLanguage(UI_LANGUAGE_ENGLISH)
   })
@@ -136,4 +129,27 @@ describe('main-i18n lazy locale loading', () => {
     expect(await setMainUiLanguage(id)).toBe('en')
     expect(translateMain('menu.file', 'File')).toBe('File')
   })
+
+  it("uses a contributed pack's plural rules and English for its empty values", async () => {
+    const id = 'plugin:orca-samples.russian/ru-RU' as const
+    setMainPluginLanguagePacks([
+      {
+        id,
+        resourceLanguage: pluginLanguageResourceId(id),
+        pluginKey: 'orca-samples.russian',
+        locale: 'ru-RU',
+        catalog: {
+          terminals_one: '{{count}} one',
+          terminals_few: '{{count}} few',
+          terminals_other: '{{count}} other',
+          empty: ''
+        }
+      }
+    ])
+    await setMainUiLanguage(id)
+    expect(
+      [1, 3, 5, 21].map((count) => translateMain('terminals_other', '{{count}} terms', { count }))
+    ).toEqual(['1 one', '3 few', '5 other', '21 one'])
+    expect(translateMain('empty', '{{count}} terminals', { count: 2 })).toBe('2 terminals')
+  })
 })

src/main/i18n/main-i18n.ts

@@ -14,13 +14,12 @@ import { isPseudoLocalizationLocale, pseudoLocalizeString } from '../../shared/p
 import { DEFAULT_UI_LOCALE, resolveUiLocale, type SupportedUiLocale } from '../../shared/ui-locale'
 import { UI_LANGUAGE_SYSTEM, type UiLanguage } from '../../shared/ui-language'
 import type { PluginLanguagePackRegistration } from '../../shared/plugins/plugin-language-pack-artifact'
+import { replacePluginLanguagePackResources } from '../../shared/plugins/plugin-language-pack-i18n-resources'
 
 export const mainI18n: I18nInstance = i18next.createInstance()
 
-let initialized = false
 let languageGeneration = 0
 let pluginLanguagePacks: readonly PluginLanguagePackRegistration[] = []
-const registeredPluginLanguages = new Set<string>()
 
 // English uses caller fallbacks; load only the selected non-English catalog after startup.
 const LAZY_LOCALE_LOADERS: Record<
@@ -67,33 +66,28 @@ export function getMainSystemLocale(): string {
   return getSystemLanguageDetection()?.locale ?? DEFAULT_UI_LOCALE
 }
 
-export async function ensureMainI18n(): Promise<I18nInstance> {
-  if (!initialized) {
-    await mainI18n.use(lazyLocaleBackend).init({
-      fallbackLng: DEFAULT_UI_LOCALE,
-      lng: DEFAULT_UI_LOCALE,
-      // Keep zh-Hant from falling back to Simplified zh before English.
-      load: 'currentOnly',
-      // Seed English as loaded; partialBundledLanguages allows lazy non-English catalogs.
-      partialBundledLanguages: true,
-      resources: {
-        en: {
-          translation: {}
-        }
-      },
-      interpolation: {
-        escapeValue: false
-      }
-    })
-    initialized = true
-    applyMainPluginLanguagePacks()
+// In-memory resources make init synchronous, so startup dialogs can translate before settings load.
+void mainI18n.use(lazyLocaleBackend).init({
+  fallbackLng: DEFAULT_UI_LOCALE,
+  lng: DEFAULT_UI_LOCALE,
+  // Keep zh-Hant from falling back to Simplified zh before English.
+  load: 'currentOnly',
+  // Seed English as loaded; partialBundledLanguages allows lazy non-English catalogs.
+  partialBundledLanguages: true,
+  resources: {
+    en: {
+      translation: {}
+    }
+  },
+  // An empty catalog value falls back to English instead of rendering blank.
+  returnEmptyString: false,
+  interpolation: {
+    escapeValue: false
   }
-  return mainI18n
-}
+})
 
 export async function setMainUiLanguage(language: UiLanguage): Promise<string> {
   const request = ++languageGeneration
-  await ensureMainI18n()
   const selectedLocale = resolveUiLocale(
     language,
     language === UI_LANGUAGE_SYSTEM ? getMainSystemLocale() : DEFAULT_UI_LOCALE
@@ -123,46 +117,21 @@ export async function prepareEarlyMainUiLanguage(): Promise<void> {
   }
 }
 
-function applyMainPluginLanguagePacks(): void {
-  for (const language of registeredPluginLanguages) {
-    mainI18n.removeResourceBundle(language, 'translation')
-  }
-  registeredPluginLanguages.clear()
-  for (const pack of pluginLanguagePacks) {
-    mainI18n.addResourceBundle(pack.resourceLanguage, 'translation', pack.catalog, true, true)
-    registeredPluginLanguages.add(pack.resourceLanguage)
-  }
-}
-
 export function setMainPluginLanguagePacks(
   packs: readonly PluginLanguagePackRegistration[]
 ): boolean {
   if (pluginLanguagePacks === packs) {
     return false
   }
+  replacePluginLanguagePackResources(mainI18n, pluginLanguagePacks, packs)
   pluginLanguagePacks = packs
-  if (initialized) {
-    applyMainPluginLanguagePacks()
-  }
   return true
 }
 
 export function translateMain(key: string, fallback: string, options?: TOptions): string {
-  // Menu registration can precede async initialization; use the English fallback then.
-  const raw = initialized
-    ? mainI18n.t(resolvePluralFamilyKey(key, options), { defaultValue: fallback, ...options })
-    : interpolateFallback(fallback, options)
-  const value = typeof raw === 'string' && raw.length > 0 ? raw : fallback
+  const value = mainI18n.t(resolvePluralFamilyKey(key, options), {
+    defaultValue: fallback,
+    ...options
+  })
   return isPseudoLocalizationLocale(mainI18n.language) ? pseudoLocalizeString(value) : value
 }
-
-// Why: startup dialogs can run before init, and their fallbacks still carry {{placeholders}}.
-function interpolateFallback(fallback: string, options: TOptions | undefined): string {
-  if (!options) {
-    return fallback
-  }
-  return fallback.replace(/\{\{\s*([\w.]+)\s*\}\}/g, (placeholder, name: string) => {
-    const value: unknown = options[name]
-    return value === undefined || value === null ? placeholder : String(value)
-  })
-}

src/main/plugins/plugin-language-pack-registry.test.ts

@@ -53,7 +53,7 @@ describe('PluginLanguagePackRegistry', () => {
       {
         id: 'plugin:orca-samples.portuguese/pt-BR',
         resourceLanguage:
-          'plugin0070006c007500670069006e003a006f007200630061002d00730061006d0070006c00650073002e0070006f00720074007500670075006500730065002f00700074002d00420052',
+          'pt-BR-x-orcapk-6f726361-2d73616d-706c6573-2e706f72-74756775-6573652f-70742d42-52',
         pluginKey: 'orca-samples.portuguese',
         locale: 'pt-BR',
         catalog: { common: { save: 'Salvar' } }

src/main/startup/main-process-i18n-menu.ts

@@ -1,5 +1,5 @@
 import { app, BrowserWindow } from 'electron'
-import { ensureMainI18n, setMainUiLanguage } from '../i18n/main-i18n'
+import { setMainUiLanguage } from '../i18n/main-i18n'
 import {
   registerAppMenu,
   rebuildAppMenu,
@@ -26,7 +26,6 @@ export async function initializeMainProcessI18nAndMenu(): Promise<void> {
   if (!store) {
     throw new Error('Store must be initialized before menu')
   }
-  await ensureMainI18n()
   await setMainUiLanguage(store.getSettings().uiLanguage)
   logStartupMilestone('i18n-ready')
   registerAppMenu({

src/main/window/renderer-recovery-prompt.test.ts

@@ -1,6 +1,6 @@
 import type { MessageBoxOptions, MessageBoxReturnValue } from 'electron'
 import { beforeEach, afterEach, describe, expect, it, vi } from 'vitest'
-import { ensureMainI18n, mainI18n } from '../i18n/main-i18n'
+import { mainI18n } from '../i18n/main-i18n'
 import type { InstallDirAclPoisonDiagnosis } from '../startup/windows-install-dir-acl-recovery'
 import {
   presentRendererRecoveryPrompt,
@@ -47,7 +47,6 @@ function harness(overrides: Partial<RendererRecoveryPromptDeps> & { responses?:
 
 describe('presentRendererRecoveryPrompt', () => {
   beforeEach(async () => {
-    await ensureMainI18n()
     await mainI18n.changeLanguage('en')
   })
 

src/renderer/src/components/github-project/ProjectRoadmap.test.tsx

@@ -112,10 +112,6 @@ describe('ProjectRoadmap', () => {
   ])('renders date ticks and bars with plugin locale %s', async (packLocale, dateLocale) => {
     const packId = 'plugin:stablyai.orca-portuguese/pt-BR' as const
     const resourceLanguage = pluginLanguageResourceId(packId)
-    // The resource tag recorded in the Windows crash report on #25021.
-    expect(resourceLanguage).toBe(
-      'plugin0070006c007500670069006e003a0073007400610062006c007900610069002e006f007200630061002d0070006f00720074007500670075006500730065002f00700074002d00420052'
-    )
     setRendererPluginLanguagePacks([
       {
         id: packId,

src/renderer/src/i18n/i18n.ts

@@ -26,6 +26,7 @@ import { DEFAULT_LOCALE, resolveUiLocale } from './supported-languages'
 import type { SupportedUiLocale } from '../../../shared/ui-locale'
 import { isPluginUiLanguage, type UiLanguage } from '../../../shared/ui-language'
 import type { PluginLanguagePackRegistration } from '../../../shared/plugins/plugin-language-pack-artifact'
+import { replacePluginLanguagePackResources } from '../../../shared/plugins/plugin-language-pack-i18n-resources'
 import { withTimeout } from '../../../shared/promise-timeout-fallback'
 import {
   resolvePluralFamilyKey,
@@ -94,6 +95,8 @@ void i18n
         translation: enRuntimeRequired
       }
     },
+    // An empty catalog value falls back to English instead of rendering blank.
+    returnEmptyString: false,
     interpolation: {
       escapeValue: false
     },
@@ -107,13 +110,6 @@ i18n.store.on('added', advanceTranslationResourceVersion)
 i18n.store.on('removed', advanceTranslationResourceVersion)
 i18n.on('languageChanged', advanceTranslationResourceVersion)
 
-// Synthetic plugin<hex> tags would get English plurals; plugin-pack-plurals.test.ts guards i18next upgrades.
-const pluralLocaleByResourceLanguage = new Map<string, string>()
-const pluralResolver = i18n.services.pluralResolver
-const getPluralRule = pluralResolver.getRule.bind(pluralResolver)
-pluralResolver.getRule = (code: string, options?: { ordinal?: boolean }) =>
-  getPluralRule(pluralLocaleByResourceLanguage.get(code) ?? code, options)
-
 // Re-rendered chrome resolves hundreds of option-free strings per workspace switch; they only change with language or resources.
 const PLAIN_TRANSLATION_CACHE_LIMIT = 5000
 const plainTranslationCache = new Map<string, string>()
@@ -171,10 +167,9 @@ export async function setRendererUiLanguage(language: UiLanguage): Promise<void>
   }
 }
 
-const registeredPluginLanguages = new Set<string>()
 let pluginLanguagePacks: readonly PluginLanguagePackRegistration[] = []
 
-/** Resolve an Intl-compatible BCP-47 tag: synthetic plugin<hex> resource names use the pack’s declared tag, then the default locale. */
+/** Resolve an Intl-compatible BCP-47 tag: plugin pack resources use the pack’s declared tag, then the default locale. */
 export function getIntlLocale(): string {
   const active = i18n.language
   const pack = pluginLanguagePacks.find((entry) => entry.resourceLanguage === active)
@@ -200,23 +195,6 @@ export function resolveRendererResourceLanguage(language: string): string {
 export function setRendererPluginLanguagePacks(
   packs: readonly PluginLanguagePackRegistration[]
 ): void {
-  for (const language of registeredPluginLanguages) {
-    i18n.removeResourceBundle(language, 'translation')
-  }
-  registeredPluginLanguages.clear()
-  pluralLocaleByResourceLanguage.clear()
+  replacePluginLanguagePackResources(i18n, pluginLanguagePacks, packs)
   pluginLanguagePacks = packs
-  for (const pack of packs) {
-    const pluralLocale = supportedIntlLocale(pack.locale, Intl.PluralRules)
-    pluralLocaleByResourceLanguage.set(pack.resourceLanguage, pluralLocale)
-    const categories = new Intl.PluralRules(pluralLocale).resolvedOptions().pluralCategories
-    i18n.addResourceBundle(
-      pack.resourceLanguage,
-      'translation',
-      withPluralCategoriesFromOther(pack.catalog, categories),
-      true,
-      true
-    )
-    registeredPluginLanguages.add(pack.resourceLanguage)
-  }
 }

src/renderer/src/i18n/intl-locale.test.ts

@@ -44,7 +44,7 @@ describe('getIntlLocale', () => {
   it('resolves a plugin resource language to the locale the pack declares', async () => {
     withSupportedLocales(['ru-RU'])
     await activate(PACK_RESOURCE, [PACK])
-    // Without the pack lookup this would reach Intl as `plugin<hex>`.
+    // Without the pack lookup this would reach Intl as the private-use resource tag.
     expect(getIntlLocale()).toBe('ru-RU')
   })
 
@@ -62,9 +62,4 @@ describe('getIntlLocale', () => {
     await activate(PACK_RESOURCE)
     expect(getIntlLocale()).toBe(DEFAULT_LOCALE)
   })
-
-  it('keeps the synthetic resource language unusable for Intl directly', () => {
-    // Unstubbed on purpose: this is a property of the tag, not of ICU data.
-    expect(() => Intl.DateTimeFormat.supportedLocalesOf(PACK_RESOURCE)).toThrow(RangeError)
-  })
 })

src/renderer/src/i18n/weekday-names.ts

@@ -1,6 +1,6 @@
 import { getIntlLocale } from './i18n'
 
-// Weekday words follow the UI language; resolve synthetic plugin tags and cache per locale for live switches.
+// Weekday words follow the UI language; resolve plugin pack tags and cache per locale for live switches.
 let cached: { locale: string; names: readonly string[] } | null = null
 
 // 2026-01-04 is Sunday: preserve cron/RRULE Sunday indexing regardless of the locale’s first weekday.

src/shared/plugins/plugin-language-pack-artifact.test.ts

@@ -8,12 +8,14 @@ import {
 } from './plugin-language-pack-artifact'
 
 describe('plugin language-pack artifacts', () => {
-  it('maps qualified IDs to distinct alphanumeric i18next resource languages', () => {
-    const first = pluginLanguageResourceId('plugin:a.bc/d-ef')
-    const second = pluginLanguageResourceId('plugin:ab.c/de-f')
+  it('maps qualified IDs to distinct canonical private-use tags on the pack locale', () => {
+    const first = pluginLanguageResourceId('plugin:a.bc/ru-RU')
+    const second = pluginLanguageResourceId('plugin:ab.c/ru-RU')
 
-    expect(first).toMatch(/^plugin[0-9a-f]+$/)
-    expect(second).toMatch(/^plugin[0-9a-f]+$/)
+    for (const resourceLanguage of [first, second]) {
+      expect(resourceLanguage).toMatch(/^ru-RU-x-orcapk-/)
+      expect(Intl.getCanonicalLocales(resourceLanguage)).toEqual([resourceLanguage])
+    }
     expect(first).not.toBe(second)
   })
 

src/shared/plugins/plugin-language-pack-artifact.ts

@@ -14,7 +14,7 @@ const PROTECTED_TRANSLATION_MODULE = /^plugin/i
 
 export type PluginLanguagePackRegistration = {
   id: `plugin:${string}`
-  resourceLanguage: `plugin${string}`
+  resourceLanguage: string
   pluginKey: string
   locale: string
   displayName?: string
@@ -40,13 +40,25 @@ export function isPluginLanguagePackRegistration(
   )
 }
 
-export function pluginLanguageResourceId(id: `plugin:${string}`): `plugin${string}` {
-  let encoded = ''
-  for (let index = 0; index < id.length; index += 1) {
-    encoded += id.charCodeAt(index).toString(16).padStart(4, '0')
+// Internal i18next ID only; settings and IPC keep the qualified `plugin:` ID.
+export function pluginLanguageResourceId(id: `plugin:${string}`): string {
+  // Fixed-width UTF-8 hex keeps IDs collision-free; private-use subtags allow at most 8 chars.
+  const encoded = Array.from(new TextEncoder().encode(id.slice('plugin:'.length)), (byte) =>
+    byte.toString(16).padStart(2, '0')
+  ).join('')
+  const subtags = encoded.match(/.{1,8}/g) ?? []
+  // The real base locale lets Intl and i18next pick the pack's plural rules natively.
+  return `${pluginPackBaseLocale(id.slice(id.lastIndexOf('/') + 1))}-x-orcapk-${subtags.join('-')}`
+}
+
+function pluginPackBaseLocale(locale: string): string {
+  try {
+    const supported = Intl.PluralRules.supportedLocalesOf(locale)[0]
+    // Unsupported tags would get the runtime's plural rules; use English like other unknown locales.
+    return supported ? new Intl.Locale(supported).baseName : 'en'
+  } catch {
+    return 'en'
   }
-  // i18next parses tag punctuation; fixed-width UTF-16 hex provides collision-free qualified-ID keys.
-  return `plugin${encoded}`
 }
 
 export type PluginLanguagePackParseResult =

src/shared/plugins/plugin-language-pack-i18n-resources.ts

@@ -0,0 +1,24 @@
+import type { i18n as I18nInstance } from 'i18next'
+import { withPluralCategoriesFromOther } from '../i18n-plural-family'
+import type { PluginLanguagePackRegistration } from './plugin-language-pack-artifact'
+
+export function replacePluginLanguagePackResources(
+  i18n: I18nInstance,
+  previous: readonly PluginLanguagePackRegistration[],
+  next: readonly PluginLanguagePackRegistration[]
+): void {
+  for (const pack of previous) {
+    i18n.removeResourceBundle(pack.resourceLanguage, 'translation')
+  }
+  for (const pack of next) {
+    const categories = new Intl.PluralRules(pack.resourceLanguage).resolvedOptions()
+      .pluralCategories
+    i18n.addResourceBundle(
+      pack.resourceLanguage,
+      'translation',
+      withPluralCategoriesFromOther(pack.catalog, categories),
+      true,
+      true
+    )
+  }
+}