My app starts breaking after I upgrade to version 1.40.1 from 1.40.0

[amanmavai]

Which project does this relate to?

Router

Describe the bug

This is the bun monorepo : https://github.com/amanmavai/mn_projects, I am working on which has one backend bun_api_space and one frontend project tanstack_router_space
It has auth setup using better-auth

The app was working fine till version 1.40.0 , below commands can verify

1. start the backend bun --filter bun_api_space dev
2. run the e2e testcases, cd to tanstack_router_space project, then run bun run test:e2e

After I have upgraded to 1.40.1, the e2e test command started failing
Also when I run the app in dev mode, its not working, it seems authClient is not defined

Your Example Website or App

https://github.com/amanmavai/mn_projects

Steps to Reproduce the Bug or Issue

1. change all the @TanStack packages in root of monorepo in the catalog section to version 1.40.1
2. run bun install
3. start the backend bun --filter bun_api_space dev
4. run the e2e testcases, cd to tanstack_router_space project, then run bun run test:e2e
5. or run the dev server and check if the app is not running

Expected behavior

Ideally the app should run fine as it was running on or before version 1.40.0

Screenshots or Videos

No response

Platform

• Router / Start Version: [e.g. 1.40.1]
• OS: macOS
• Browser: Chrome

Additional context

No response

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🔗 Related PRs

#5406 - fix(router-devtools-core): bundle solid for smaller package [merged]
#5422 - fix(router-devtools-core): actually bundle solid [merged]
#5474 - chore: bump @tanstack/config to v0.22.0 [merged]
#5680 - fix(router): bump tanstack store to ^0.8 [merged]

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[schiller-manuel]

please try latest version, and if that doesn't work either, please provide error messages.

[amanmavai]

Yes, I have tried with latest version as well, getting the same issue.

I get the following error when I am running in dev mode

TypeError: Cannot read properties of undefined (reading 'useSession')
    at SignedOut (auth-components.tsx:22:49)
    at Object.react_stack_bottom_frame (react-dom_client.js?v=cc2383de:18509:20)
    at renderWithHooks (react-dom_client.js?v=cc2383de:5654:24)
    at updateFunctionComponent (react-dom_client.js?v=cc2383de:7475:21)
    at beginWork (react-dom_client.js?v=cc2383de:8525:20)
    at runWithFiberInDEV (react-dom_client.js?v=cc2383de:997:72)
    at performUnitOfWork (react-dom_client.js?v=cc2383de:12561:98)
    at workLoopSync (react-dom_client.js?v=cc2383de:12424:43)
    at renderRootSync (react-dom_client.js?v=cc2383de:12408:13)
    at performWorkOnRoot (react-dom_client.js?v=cc2383de:11827:37)

actually on or before 1.40.0 version, Signout component was not being executed I believe, only after the beforeLoad of __root executes completely then other components start executing. it seems that has changed somehow now.

[schiller-manuel]

would be great if you could strip down the reproducer to the bare minimum

[amanmavai]

I have created another tanstack router repo which is CSR app, with this app, we are able to reproduce the issue without the backend.
https://github.com/amanmavai/tanstack_router_open/tree/main

use following commands

1. bun install
2. bun run dev
3. you will see the error

after you update the version back to 1.40.0, the error goes away.

Kindly see below images with console logs, there is a difference in the sequence of logs:

version 1.40.0

version 1.40.1

in the above images, we see after we upgrade to the faulty version, the logs changes a bit towards the end.

during my debugging, in the new falty version, the authClient is defined during the beforeLoad execution after authClient is awaited. but its not available in SignedOut component when we access it using useAuthClient() hook

[amanmavai]

It seems this might be because of the way I access root route context in this code

// common.hooks.ts
import {getRouteApi, rootRouteId} from "@tanstack/react-router";

const routeApi = getRouteApi(rootRouteId);

export const useAuthClient = () => {
  const {authClient} = routeApi.useRouteContext();
  return authClient;
};

is this way not supported anymore? esp on or after 1.40.1. if so what is the correct way to access root route context in a common hook

[amanmavai]

I tried to dig through the router code using cursor, and found this info below, hope this would be useful for you guys

Title: getRouteApi().useRouteContext() returns undefined for beforeLoad context values in v1.140.1+

The change in PR #6053 ("commit route context") defers context updates until after the loader completes.

For routes without a loader, useRouteContext() returns undefined for values returned from beforeLoad.

Regression in: v1.140.1
Working in: v1.140.0

Root cause: packages/router-core/src/load-matches.ts now only calls commitContext() 
after the loader, but useRouteContext() reads match.context which is not updated 
after beforeLoad alone.