Module Federation: singleton: true not working — remotes bundle separate copies of react-oidc-context

[nicatabdullay3v]

I have a host app with multiple remotes using @module-federation/vite.

Even though all shared deps are configured with singleton: true, each remote still bundles its own full copy of react-oidc-context instead of reusing the host’s instance.

Because of that, every remote creates its own AuthContext, so useAuth() returns undefined inside remotes.

What I see

In the Network tab, the react-oidc-context chunk loaded from remotes contains the full library code, for example:

var AuthContext = React.createContext(void 0);
var AuthProvider = (props) => { ...full implementation... }

This should be a stub referencing the host’s shared singleton, not a full bundled copy.

Strange part

I have two host apps using the same remotes and almost identical federation config:

web-portal → works correctly
admin-portal → broken

In web-portal, only one shared copy of react-oidc-context is used.
In admin-portal, each remote loads its own copy.

Result

With only 1 remote connected, everything works.
With 2 or more remotes, it breaks consistently on page load.

Errors

Most common error:

TypeError: Cannot read properties of undefined (reading 'user')

Also:

AuthProvider context is undefined, please verify you are calling useAuth() as child of a component.

And when trying import: false:

Shared module 'react-oidc-context' must be provided by host
Why I think shared modules are not actually shared

One error stack shows usePermissions from one remote and React renderer code from another remote, which strongly suggests multiple isolated React / context instances are running.

Expected

Remotes should consume the host’s singleton instance of react-oidc-context.

Actual

Each remote loads its own full copy of react-oidc-context, creating separate contexts and breaking useAuth().

Versions
@module-federation/vite: ^1.12.3

All apps use singleton: true for:

react
react-dom
react-router-dom
react-redux
@reduxjs/toolkit
react-oidc-context
oidc-client-ts