`/__manifest` requests and 404 (no match) requests do not pass through root middleware

[richardscarrott]

Reproduction

https://stackblitz.com/edit/github-mdayxhkg?file=app%2Froot.tsx

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @react-router/dev: ^7.7.1 => 7.8.0 
    @react-router/node: ^7.7.1 => 7.8.0 
    @react-router/serve: ^7.7.1 => 7.8.0 
    react-router: ^7.7.1 => 7.8.0 
    vite: ^6.3.3 => 6.3.5

Used Package Manager

npm

Expected Behavior

All requests, including /__manifest and 404 (no match), should run through root middleware so common logic (logging, response headers, cleanup, etc.) executes consistently.

Actual Behavior

Neither /__manifest nor 404 (no match) requests run through middleware.

I'm working around the latter by explicitly defining a 404 route:

// routes/$/route.tsx
import { data } from "react-router";

export const loader = async () => {
  throw data(null, { status: 404 });
};

// Opt-out of resource route behaviour
export default () => null;

For the same reasons discussed in #13766 (comment), it's important all requests going in and out of the server go through middleware.

[brophdawg11]

React Router middleware is not trying to be 1:1 with HTTP server middleware. Our middleware is route based and runs for matched routes.

• __manifest is not handled by your route tree - do middeware doesn't apply - you can still do this via an HTTP server middleware
• You have the correct solution for 404's - you have to opt into handling/matching those with a catch-all if you want them to match the route tree

If you really want a "global runs on any request you pass to the handler," you can open a proposal but I consider that out of scope for our current route-based middleware API.