redirects don't work properly with i18n and basepath

What version of Next.js are you using?

10.0.5

What version of Node.js are you using?

12.16.1

What browser are you using?

Chrome

What operating system are you using?

Windows

How are you deploying your application?

docker / k8s

Describe the Bug

I’m developing a nextjs app that should be deployed at /my-base-path. I wanted to redirect / to /my-base-path, and I setup next.config.js accordingly:

const basePath = '/my-base-path';

const nextConfig = {
    basePath,
    env: {
        BASE_PATH: basePath,
    },
    redirects: async () => ([
        {
            source: '/',
            destination: basePath,
            permanent: false,
            basePath: false,
        },
    ])
};
module.exports = nextConfig;

Everything works as expected: / redirects to /my-base-path.

Once I add an i18n config to nextConfig, redirects don’t function as I expect:

const basePath = '/my-base-path';

const nextConfig = {
    basePath,
    env: {
        BASE_PATH: basePath,
    },
    i18n: {
        defaultLocale: 'en',
        locales: ['en', 'es'],
    },
    redirects: async () => ([
        {
            source: '/',
            destination: basePath,
            permanent: false,
            basePath: false,
        },
    ])
};
module.exports = nextConfig;

Expected Behavior

• / should redirect to /my-base-path, but / just returns a 404.
• /en redirects to /en/my-base-path, and /en/my-base-path returns a 404.
• /my-base-path/en renders the welcome page, but I would expect it to redirect to /my-base-path.
• /my-base-path renders the welcome page as expected. 👍

To Reproduce

A repo demonstrating this behavior exists at https://github.com/ckeeney/nextjs-redirect-i18n-basepath

It’s unclear to me whether the correct path structure is /{locale}/{basePath}/{page} or /{basePath}/{locale}/{page}.

I think the former would make a more consistent URL pattern across multiple zones, but I’m a bit nervous about how complicated that would make the routing rules for the reverse proxy. For the latter option we can simply route all traffic for each base path to it’s designated nextjs app, matching on basePath as you would expect. The former requires that the load balancer have some way of handling the locales, and I’m not sure the more predictable locale URLs are worth that trouble.

[giovas94]

Any update about this issue? Tks

[gsambrotta]

Same here, trying to use the multi zone example and having problem with /en/blog/