Don't change language when config with localePrefix='never' and localeDetection = false

[navata]

Description

I have download and run your demo with url https://github.com/amannn/next-intl/tree/main/examples/example-app-router
And i use config localeDetection = false in middleware, after function change language not working

File define const:

import {Pathnames} from 'next-intl/navigation';

export const locales = ['en', 'de'] as const;

export const pathnames = {
  '/': '/',
  '/pathnames': {
    en: '/pathnames',
    de: '/pfadnamen'
  }
} satisfies Pathnames<typeof locales>;

// Use the default: `always`
export const localePrefix = 'never';

export type AppPathnames = keyof typeof pathnames;

export const localeDetection = false;

File middleware:

import {pathnames, locales, localePrefix, localeDetection} from './config';
export default createMiddleware({
  localePrefix,
  localeDetection,
});

Mandatory reproduction URL

https://github.com/navata/examples-example-app-router

Reproduction description

Steps to reproduce:

1. git clone https://github.com/navata/examples-example-app-router.git
2. npm i
3. npm run dev
4. change language on navbar -> it don't change language

Expected behaviour

I want to change language when i use localePrefix='never' and localeDetection = false

[amannn]

If you use localePrefix: 'never' and localeDetection: false, the only remaining place where the locale can be resolved from is the domain, in case you use domain-based routing. If you use a single domain (or you have multiple locales per domain), you shouldn't disable localeDetection.

Can you share some background why you'd want to use this configuration?

[navata]

Thank you for your response.
However, I would like the user to be able to control the language on my e-commerce website. All traffic will be directed to the same domain, which is advantageous for SEO.
You can review prominent e-commerce websites such as https://shopee.vn/ or https://www.lazada.vn/.

[amannn]

shopee.vn unfortunately redirects me and I'm not able to use their language switcher. lazada.vn uses different domains for different locales, that's equivalent to domain-based routing in next-intl.

I'll move this to a discussion for the time being as this seems to be a usage question.