Custom worker entrypoint returns 500: `FetchState(request) called on a request without an attached app`

Astro Info

Astro                    v7.1.6
Vite                     v8.2.0
Node                     v24.19.0
System                   Linux (x64)
Package Manager          pnpm
Output                   server
Adapter                  @astrojs/cloudflare (v14.1.7)
Integrations             none

wrangler 4.118.0, compatibility_date 2026-08-04.

Describe the Bug

The Cloudflare adapter documents a custom worker entrypoint that combines cf() with the advanced
routing handlers, for cases such as exporting a Durable Object:
https://docs.astro.build/en/guides/integrations-guide/cloudflare/#using-advanced-routing

Following that page, every request that reaches the worker returns 500:

Error: FetchState(request) called on a request without an attached app. Ensure it runs inside Astro's request pipeline.

src/worker.ts is the documented example, unchanged:

import { astro, FetchState } from 'astro/fetch';
import { cf } from '@astrojs/cloudflare/fetch';

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    const state = new FetchState(request);
    const asset = await cf(state, env, ctx);
    if (asset) return asset;
    return astro(state);
  },
};

Files under public/ still return 200, because the assets layer answers them before the worker
runs. Everything Astro would render fails.

Pointing main back at @astrojs/cloudflare/entrypoints/server in the same project makes the page
return 200, so nothing else in the setup is at fault.

Expected

The documented entrypoint serves pages.

Where it comes from

FetchState resolves its pipeline from the request:

// astro/dist/core/fetch/index.js
function getApp(request) {
  const app = Reflect.get(request, appSymbol);
  if (!app) throw new Error("FetchState(request) called on a request without an attached app. …");
  return app;
}

class FetchState extends BaseFetchState {
  constructor(request) { super(getApp(request).pipeline, request); }
}

appSymbol is Symbol.for("astro.app"). The only place in astro/dist that writes it is
BaseApp.render(), at core/app/base.js:242 and :246. The one other occurrence,
core/fetch/fetch-state.js:821, carries an already-attached app across a rewrite.

A custom worker entrypoint replaces the adapter's default handler, and that handler is what calls
app.render(). So the app is never attached, and cf() throws on its first line before doing any
work.

The same applies to the Hono example further down that page. cf() from @astrojs/cloudflare/hono
opens with getFetchState(), which builds the same FetchState from a bare request. I hit it that
way first, in a separate project; this repro uses the Fetch API version because it needs one fewer
dependency to show the same thing.

Nothing is exported for attaching the app either. astro/fetch narrows the base constructor
(pipeline, request, options) down to FetchState(request), so a user entrypoint has no supported
way to supply one.

What makes it work

Setting the symbol by hand before cf() runs is enough:

import { createApp } from 'astro/app/entrypoint';

const app = createApp();

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    Reflect.set(request, Symbol.for('astro.app'), app);
    // … documented body unchanged
  },
};

With that one line added, the repro serves its page. I also ran it against a larger SSR project,
where routing, trailing-slash redirects, 404 pages, and static assets through the ASSETS binding all
behaved as they had on the default entrypoint.

It is not something to recommend, since it depends on an internal symbol and creates a second App
next to the one cf() keeps module-private. Two directions that would avoid both:

• have cf() attach the app itself. It already holds one through ensureInitialized() and
  currently just receives a FetchState that was constructed too early.
• export something like createFetchState(app, request) from astro/fetch and use it in the
  documented examples.

Steps to Reproduce

Repro: https://github.com/iseraph-dev/repro-astro-worker-appsymbol

pnpm install
pnpm types
pnpm build
pnpm preview
curl -i http://localhost:4321/

Returns 500. Change main in wrangler.json to @astrojs/cloudflare/entrypoints/server, rebuild,
and the same request returns 200.