Crash when using @cloudflare/vite-plugin + Cloudflare D1 and hot reloading

[nihalgonsalves]

Reproduction:

• Start from https://github.com/wakujs/waku/tree/7b73f88fd668dc249f6c357f37f6e979b927132e/examples/07_cloudflare

• Add a D1 database to wrangler.jsonc (optionally run npx wrangler types)

   "d1_databases": [
   	{
   		"binding": "test_db",
   		"database_name": "test_db",
   	},
   ],

• Make a query in a server component:

   import { env } from "cloudflare:workers";
  
   // ...
  
   const result = await env.test_db.prepare(
     "SELECT  1",
   )
     .run();

This works in general, but as soon as you trigger a hot reload by saving somewhere, you get this in the server logs:

9:25:54 AM [vite] (rsc) hmr update /@id/virtual:cloudflare/worker-entry, /src/styles.css
Warning: A promise was resolved or rejected from a different request context than the one it was created in. However, the creating request has already been completed or canceled. Continuations for that request are unlikely to run safely and have been canceled. If this behavior breaks your worker, consider setting the `no_handle_cross_request_promise_resolution` compatibility flag for your worker.
    at CustomModuleRunner.import (workers/runner-worker.js:1045:10)
Warning: A promise was resolved or rejected from a different request context than the one it was created in. However, the creating request has already been completed or canceled. Continuations for that request are unlikely to run safely and have been canceled. If this behavior breaks your worker, consider setting the `no_handle_cross_request_promise_resolution` compatibility flag for your worker.
    at CustomModuleRunner.import (workers/runner-worker.js:1045:10)

After a moment, the browser tab will also crash with this message:

Error: The Workers runtime canceled this request because it detected that your Worker's code had hung and would never generate a response. Refer to: https://developers.cloudflare.com/workers/observability/errors/
    at async Object.fetch (file:///< repository>/node_modules/.pnpm/miniflare@4.20260305.0/node_modules/miniflare/dist/src/workers/core/entry.worker.js:4497:22)

If you add the no_handle_cross_request_promise_resolution flag as the first error says, you'll get this error instead:

[vite] hot updated: virtual:cloudflare/worker-entry
[SSR Error]
    at fn (<repository>/node_modules/.vite/deps_ssr/react-server-dom-webpack_client__edge.js?v=37af8570:2405:20)
    at fn (<repository>/node_modules/.vite/deps_ssr/react-server-dom-webpack_client__edge.js?v=37af8570:2405:20)
 Error: Cannot perform I/O on behalf of a different request. I/O objects (such as streams, request/response bodies, and others) created in the context of one request handler cannot be accessed from a different request's handler. This is a limitation of Cloudflare Workers which allows us to improve overall performance. (I/O type: SpanParent)
    at RpcProperty.<anonymous> (<anonymous>)
    at CustomModuleRunner.cachedModule (workers/runner-worker.js:1196:76)
    at request (workers/runner-worker.js:1123:94)
    at dynamicRequest (workers/runner-worker.js:1125:122)
    at Object.load (<repository>/node_modules/.pnpm/@vitejs+plugin-rsc@0.5.21_react-dom@19.2.4_react@19.2.4__react-server-dom-webpack@19.2._336fd4df9d8e62120fabaccf47fa08cf/node_modules/@vitejs/plugin-rsc/dist/ssr.js:22:10)
    at <repository>/node_modules/.pnpm/@vitejs+plugin-rsc@0.5.21_react-dom@19.2.4_react@19.2.4__react-server-dom-webpack@19.2._336fd4df9d8e62120fabaccf47fa08cf/node_modules/@vitejs/plugin-rsc/dist/core/ssr.js:10:18
    at <repository>/node_modules/.pnpm/@vitejs+plugin-rsc@0.5.21_react-dom@19.2.4_react@19.2.4__react-server-dom-webpack@19.2._336fd4df9d8e62120fabaccf47fa08cf/node_modules/@vitejs/plugin-rsc/dist/dist-yW9-EeG1.js:34:22
    at globalThis.__vite_rsc_require__ (<repository>/node_modules/.pnpm/@vitejs+plugin-rsc@0.5.21_react-dom@19.2.4_react@19.2.4__react-server-dom-webpack@19.2._336fd4df9d8e62120fabaccf47fa08cf/node_modules/@vitejs/plugin-rsc/dist/shared-Dhw3vs8e.js:16:21)
    at requireAsyncModule (<repository>/node_modules/.vite/deps_ssr/react-server-dom-webpack_client__edge.js:53:23)
    at preloadModule (<repository>/node_modules/.vite/deps_ssr/react-server-dom-webpack_client__edge.js:83:64)
[vite] program reload

[dai-shi]

Thanks for reporting!
Could you investigate if this is Waku only issue, or if it can happen with pure @cloudflare/vite-plugin setup?

[nihalgonsalves]

Good call, thanks! I followed Cloudflare's own guide + TanStack Start (to emulate Vite environments) https://developers.cloudflare.com/workers/framework-guides/web-apps/tanstack-start/

npm create cloudflare@latest -- my-tanstack-start-app --framework=tanstack-start

and made this test with the same SQL query in a `createServerFn`:

import { createFileRoute } from "@tanstack/react-router";
import { env } from "cloudflare:workers";

import { createServerFn } from "@tanstack/react-start";

const serverLoader = createServerFn({ method: "GET" }).handler(async () => {
  const result = await env.test_db.prepare("SELECT 456").run();
  return result;
});

export const Route = createFileRoute("/")({
  loader: async () => {
    return serverLoader();
  },
  component: App,
});

function App() {
  const result = Route.useLoaderData();

  return <div className="">{JSON.stringify({ result })}</div>;
}

It generally works, but I can indeed get it to eventually throw an error if I hot reload enough.

This seems relevant: cloudflare/workers-sdk#9518 (and the linked cloudflare/workers-sdk#9993)

Interestingly while creating a reproduction repo, I found that it's easier to trigger this specific issue via Safari (rather than Chrome). Maybe that helps pinpointing where exactly there's an issue.

I created a new issue in the Cloudflare repo here: cloudflare/workers-sdk#12731

[nihalgonsalves]

Turns out that this is two separate issues, one that needs to be fixed in Waku:

...

Additionally, in Waku specifically, the cachedElementsForRequest map can lead to the following error:

Warning: A promise was resolved or rejected from a different request context than the one it was created in. However, the creating request has already been completed or canceled. Continuations for that request are unlikely to run safely and have been canceled.

...

cloudflare/workers-sdk#12731 (comment)