redirectOn: 'no prefix' does not redirect on the root URL

[phanect]

Environment

(Here's Stackblitz' environment information)

• Operating System: Linux
• Node Version: v16.14.2
• Nuxt Version: 3.5.2
• Nitro Version: 2.4.1
• Package Manager: [email protected]
• Builder: vite
• User Config: ssr, components, modules, i18n
• Runtime Modules: @nuxtjs/[email protected]
• Build Modules: -

Reproduction

https://stackblitz.com/edit/nuxt-starter-2yxmzd

Describe the bug

I added strategy: 'prefix' and redirectOn: 'no prefix' to nuxt.config.ts.

nuxt.config.ts

export default defineNuxtConfig({
  // ...
  i18n: {
    // ...
    strategy: 'prefix',
    // ...
    detectBrowserLanguage: {
      useCookie: true,
      cookieSecure: true,
      alwaysRedirect: true,
      fallbackLocale: 'en',
      redirectOn: 'no prefix',
    },
  },
});

If I understand correctly, with this config, if you open / (root URL), it should return 302 and redirect to /en or /ja. (Depending on your Accept-Language)
However, when you open / (root URL), it returns 404.

Additional context

No response

Logs

No response

[phanect]

This issue might be related to #2131.

[phanect]

I guess the following code causes this issue:

i18n/src/runtime/utils.ts

Lines 294 to 299 in 8dc25cb

	let redirectPath = ''
	const isStaticGenerate = isSSG && process.server
	if (!isI18nRouteDefined(route)) {
	return redirectPath
	}

isI18nRouteDefined(route) always returns false because route.matched[0]?.meta.nuxtI18n is always undefined on my end. (see the following isI18nRouteDefined() function:

i18n/src/runtime/utils.ts

Lines 514 to 517 in 8dc25cb

	function isI18nRouteDefined(route: Route | RouteLocationNormalized | RouteLocationNormalizedLoaded): boolean {
	const i18nLocales = route.matched[0]?.meta.nuxtI18n
	return i18nLocales ? Object.keys(i18nLocales).length > 0 : false
	}

Therefore, detectRedirect() returns redirectPath (=== empty string ('')) and the following redirection process is not executed.

I'm stuck here because I'm unsure how to make route.matched[0]?.meta.nuxtI18n a non-undefined value...

[kazupon]

Thanks!

You can workaround with dedefaultLocale option.

BTW, docs recommend that it is specified default locale
https://v8.i18n.nuxtjs.org/guide/routing-strategies#configuration

[phanect]

@kazupon Thanks for the information.
However, setting defaultLocale does not solve the problem.

In the following repro, I set defaultLocale: "en".

https://stackblitz.com/edit/nuxt-starter-aj1bpj

However, / returns 200 and shows the English content, while it should return 302 to redirect to /en or /ja (Depending on your Accept-Language).

[urbgimtam]

@phanect Suffering the same issue.

[kazupon]

I seem that this issue is degraded by #1902
I'll try to revert that PR.

[phanect]

@kazupon Thanks so much for working on this! I confirmed this issue is partially fixed in v8.0.0-beta.13.

Now if you open https://example.com/, it automatically redirects to https://example.com/en.
However, it does not redirect to https://example.com/ja when you open the root page with Accept-Language: ja. It always redirects to https://example.com/en.

Here's the repro.
https://github.com/phanect/repro-nuxt-i18n-redirection

Note: This sample code is available on Stackblitz too, but Stackblitz seems to have a bug as of now and it didn't work as expected. Please clone the repro and run it on your local machine.

Here's step to reproduce:

1. Run npm run dev at the project root of the repro.
2. Open your browser settings to set your primary language "Japanese" so that the Accept-Language header would be ja. This issue happens when Accept-Language is something like ja,en;q=0.9,en-US;q=0.8 too.
3. Open any page under http://localhost:3000/, open the browser developer tools (Chrome: Application panel, Firefox: Storage panel), and remove i18n_redirected cookie.
4. Open http://localhost:3000/ (root page)

Expected: The browser redirects you to http://localhost:3000/ja
Actual: The browser redirects you to http://localhost:3000/en

Let me know if you prefer to close this issue and open another issue for Accept-Language bug.