per-locale bundle & inline locale (#16369)

* feat: split entry file by locale name

* chore: とりあえず transform hook で雑に分割

* chore: とりあえず transform 結果をいい感じに

* chore: concurrent buildで高速化

* chore: vite ではローケルのないものをビルドして後処理でどうにかするように

* chore: 後処理のためにi18n.jを単体になるように切り出す

* chore: use typescript

* chore: remove unref(i18n) in vite build process

* chore: inline variable

* fix: build error

* fix: i18n.ts.something.replaceAll() become error

* chore: ignore export specifier from error

* chore: support i18n.tsx as object

* chore: process literal for all files

* chore: split config and locale

* chore: inline locale name

* chore: remove updating locale in boot common

* chore: use top-level await to load locales

* chore: inline locale

* chore: remove loading locale from boot.js

* chore: remove loading locale from boot.js

* コメント追加

* fix test; fetchに失敗する

* import削除ログをdebugレベルに

* fix: watch pug

* chore: use hash for entry files

* chore: remove es-module-lexer from dependencies

* chore: move to frontend-builder

* chore: use inline locale in embed

* chore: refetch json on hot reload

* feat: store localization related to boot.js in backend in bootloaderLocales localstorage

* 応急処置を戻す

* fix spex

* fix `Using i18n identifier "e" directly. Skipping inlining.` warning

* refactor: use scriptsDir parameter

* chore: remove i18n from depmap

* chore: make build crash if errors

* error -> warn few conditions

* use inline object

* update localstorage keys

* remove accessing locale localstorage

* fix: failed to process i18n.tsx.aaa({x:i18n.bbb})

5 files changed, 70 insertions, 21 deletions

diff --git a/packages/frontend-embed/build.ts b/packages/frontend-embed/build.ts
new file mode 100644
index 0000000000..737233a4d0
--- /dev/null
+++ b/packages/frontend-embed/build.ts
@@ -0,0 +1,51 @@
+import * as fs from 'fs/promises';
+import url from 'node:url';
+import path from 'node:path';
+import { execa } from 'execa';
+import locales from '../../locales/index.js';
+import { LocaleInliner } from '../frontend-builder/locale-inliner.js'
+import { createLogger } from '../frontend-builder/logger';
+
+// requires node 21 or later
+const __dirname = path.dirname(url.fileURLToPath(import.meta.url));
+const outputDir = __dirname + '/../../built/_frontend_embed_vite_';
+
+/**
+ * @return {Promise<void>}
+ */
+async function viteBuild() {
+	await execa('vite', ['build'], {
+		cwd: __dirname,
+		stdout: process.stdout,
+		stderr: process.stderr,
+	});
+}
+
+
+async function buildAllLocale() {
+	const logger = createLogger()
+	const inliner = await LocaleInliner.create({
+		outputDir,
+		logger,
+		scriptsDir: 'scripts',
+		i18nFile: 'src/i18n.ts',
+	})
+
+	await inliner.loadFiles();
+
+	inliner.collectsModifications();
+
+	await inliner.saveAllLocales(locales);
+
+	if (logger.errorCount > 0) {
+		throw new Error(`Build failed with ${logger.errorCount} errors and ${logger.warningCount} warnings.`);
+	}
+}
+
+async function build() {
+	await fs.rm(outputDir, { recursive: true, force: true });
+	await viteBuild();
+	await buildAllLocale();
+}
+
+await build();
diff --git a/packages/frontend-embed/package.json b/packages/frontend-embed/package.json
index e76046add3..f9d1330ae5 100644
--- a/packages/frontend-embed/package.json
+++ b/packages/frontend-embed/package.json
@@ -4,7 +4,7 @@
 	"type": "module",
 	"scripts": {
 		"watch": "vite",
-		"build": "vite build",
+		"build": "tsx build.ts",
 		"typecheck": "vue-tsc --noEmit",
 		"eslint": "eslint --quiet \"src/**/*.{ts,vue}\"",
 		"lint": "pnpm typecheck && pnpm eslint"
@@ -20,8 +20,8 @@
 		"astring": "1.9.0",
 		"buraha": "0.0.1",
 		"estree-walker": "3.0.3",
-		"icons-subsetter": "workspace:*",
 		"frontend-shared": "workspace:*",
+		"icons-subsetter": "workspace:*",
 		"json5": "2.2.3",
 		"mfm-js": "0.25.0",
 		"misskey-js": "workspace:*",
@@ -63,6 +63,7 @@
 		"nodemon": "3.1.10",
 		"prettier": "3.6.2",
 		"start-server-and-test": "2.0.12",
+		"tsx": "4.20.3",
 		"vite-plugin-turbosnap": "1.0.3",
 		"vue-component-type-helpers": "3.0.5",
 		"vue-eslint-parser": "10.2.0",
diff --git a/packages/frontend-embed/src/boot.ts b/packages/frontend-embed/src/boot.ts
index 459b283e23..9d69437c30 100644
--- a/packages/frontend-embed/src/boot.ts
+++ b/packages/frontend-embed/src/boot.ts
@@ -17,15 +17,16 @@ import { createApp, defineAsyncComponent } from 'vue';
 import defaultLightTheme from '@@/themes/l-light.json5';
 import defaultDarkTheme from '@@/themes/d-dark.json5';
 import { MediaProxy } from '@@/js/media-proxy.js';
+import { storeBootloaderErrors } from '@@/js/store-boot-errors';
 import { applyTheme, assertIsTheme } from '@/theme.js';
 import { fetchCustomEmojis } from '@/custom-emojis.js';
 import { DI } from '@/di.js';
 import { serverMetadata } from '@/server-metadata.js';
-import { url, version, locale, lang, updateLocale } from '@@/js/config.js';
+import { url, version, lang } from '@@/js/config.js';
 import { parseEmbedParams } from '@@/js/embed-page.js';
 import { postMessageToParentWindow, setIframeId } from '@/post-message.js';
 import { serverContext } from '@/server-context.js';
-import { i18n, updateI18n } from '@/i18n.js';
+import { i18n } from '@/i18n.js';
 
 import type { Theme } from '@/theme.js';
 
@@ -76,19 +77,7 @@ if (embedParams.colorMode === 'dark') {
 //#endregion
 
 //#region Detect language & fetch translations
-const localeVersion = localStorage.getItem('localeVersion');
-const localeOutdated = (localeVersion == null || localeVersion !== version || locale == null);
-if (localeOutdated) {
-	const res = await window.fetch(`/assets/locales/${lang}.${version}.json`);
-	if (res.status === 200) {
-		const newLocale = await res.text();
-		const parsedNewLocale = JSON.parse(newLocale);
-		localStorage.setItem('locale', newLocale);
-		localStorage.setItem('localeVersion', version);
-		updateLocale(parsedNewLocale);
-		updateI18n(parsedNewLocale);
-	}
-}
+storeBootloaderErrors({ ...i18n.ts._bootErrors, reload: i18n.ts.reload });
 //#endregion
 
 // サイズの制限
diff --git a/packages/frontend-embed/src/i18n.ts b/packages/frontend-embed/src/i18n.ts
index 6ad503b089..0b2b206b7e 100644
--- a/packages/frontend-embed/src/i18n.ts
+++ b/packages/frontend-embed/src/i18n.ts
@@ -5,11 +5,12 @@
 
 import { markRaw } from 'vue';
 import { I18n } from '@@/js/i18n.js';
+import { locale } from '@@/js/locale.js';
 import type { Locale } from '../../../locales/index.js';
-import { locale } from '@@/js/config.js';
 
 export const i18n = markRaw(new I18n<Locale>(locale, _DEV_));
 
+// test 以外では使わないこと。インライン化されてるのでだいたい意味がない
 export function updateI18n(newLocale: Locale) {
 	i18n.locale = newLocale;
 }
diff --git a/packages/frontend-embed/vite.config.ts b/packages/frontend-embed/vite.config.ts
index a057581b3a..eb57db9774 100644
--- a/packages/frontend-embed/vite.config.ts
+++ b/packages/frontend-embed/vite.config.ts
@@ -8,6 +8,7 @@ import locales from '../../locales/index.js';
 import meta from '../../package.json';
 import packageInfo from './package.json' with { type: 'json' };
 import pluginJson5 from './vite.json5.js';
+import pluginRemoveUnrefI18n from '../frontend-builder/rollup-plugin-remove-unref-i18n';
 
 const url = process.env.NODE_ENV === 'development' ? yaml.load(await fsp.readFile('../../.config/default.yml', 'utf-8')).url : null;
 const host = url ? (new URL(url)).hostname : undefined;
@@ -85,6 +86,7 @@ export function getConfig(): UserConfig {
 
 		plugins: [
 			pluginVue(),
+			pluginRemoveUnrefI18n(),
 			pluginJson5(),
 		],
 
@@ -135,15 +137,20 @@ export function getConfig(): UserConfig {
 			manifest: 'manifest.json',
 			rollupOptions: {
 				input: {
-					app: './src/boot.ts',
+					i18n: './src/i18n.ts',
+					entry: './src/boot.ts',
 				},
 				external: externalPackages.map(p => p.match),
+				preserveEntrySignatures: 'allow-extension',
 				output: {
 					manualChunks: {
 						vue: ['vue'],
+						// dependencies of i18n.ts
+						'config': ['@@/js/config.js'],
 					},
-					chunkFileNames: process.env.NODE_ENV === 'production' ? '[hash:8].js' : '[name]-[hash:8].js',
-					assetFileNames: process.env.NODE_ENV === 'production' ? '[hash:8][extname]' : '[name]-[hash:8][extname]',
+					entryFileNames: 'scripts/[hash:8].js',
+					chunkFileNames: 'scripts/[hash:8].js',
+					assetFileNames: 'assets/[hash:8][extname]',
 					paths(id) {
 						for (const p of externalPackages) {
 							if (p.match.test(id)) {