middleware server is not sending context to loader and beforeLoad

[cjoecker]

Which project does this relate to?

Router

Describe the bug

Server middleware returning context values cannot be accessed on the loader or beforeLoad

Your Example Website or App

I couldn't finde a stackblitz with Tanstack Start. When I tried to install it, I get a lot of type errors.

Steps to Reproduce the Bug or Issue

Create a route with context like this:

import { createFileRoute } from "@tanstack/react-router";
import { createMiddleware } from "@tanstack/react-start";

const authMiddleware = createMiddleware().server(async ({ next }) => {
	return next({
		context: {
			auth: {
				isAuthenticated: true,
			},
		},
	});
});

export const Route = createFileRoute("/$locale/_auth")({
	server: {
		middleware: [authMiddleware],
	},
	loader: ({ context }) => {
		console.log(context);
	},
});

See in the log that isAuthenticated=false

Expected behavior

The log shows isAuthenticated=true

Screenshots or Videos

No response

Platform

    "@tanstack/react-devtools": "^0.7.0",
    "@tanstack/react-form": "^1.0.0",
    "@tanstack/react-router": "^1.132.0",
    "@tanstack/react-router-devtools": "^1.132.0",
    "@tanstack/react-router-ssr-query": "^1.131.7",
    "@tanstack/react-start": "^1.132.0",
    "@tanstack/router-plugin": "^1.132.0",

Additional context

PS: I couldn't find in the docs if beforeLoad runs in the client or the server. It would be nice to have better docs for that function