Deserialization error when using async generators from server functions

[Zuruuh]

Which project does this relate to?

Start

Describe the bug

When defining a streamable server function (with an async function*), I can consistently get the deserialization to fail, preventing me from doing anything further

Stack Trace

Invalid JSON: {"t":32,"i":5,"f":{"t":10,"i":9,"p":{"k":["hello"],"v":[{"t":1,"s":"world"}]},"o":0}}
 Error: Seroval caught an error during the deserialization process.

Error
Malformed node type "32".

- For more information, please check the "cause" property of this error.
- If you believe this is an error in Seroval, please submit an issue at https://github.com/lxsmnsyc/seroval/issues/new
    SerovalError errors.ts:51
    SerovalDeserializationError errors.ts:69
    deserializeTop deserializer.ts:858
    fromCrossJSON index.ts:189
    onMessage serverFnFetcher.ts:289
    drain serverFnFetcher.ts:391
    processFramedResponse serverFnFetcher.js:226
    getResponse serverFnFetcher.ts:287
    serverFnFetcher serverFnFetcher.ts:167
    clientFn createClientRpc.ts:12
    client createServerFn.ts:921
    callNextMiddleware createServerFn.ts:313
    executeMiddleware createServerFn.ts:353
    handler createServerFn.ts:150
    onClick index.tsx:17
    React 13
    <anonymous> client.tsx:6
    startTransition React
    <anonymous> client.tsx:5
Caused by: Error: Malformed node type "32".
    SerovalMalformedNodeError errors.ts:170
    validateNodeType deserializer.ts:368
    deserializeStreamNext deserializer.ts:695
    deserialize deserializer.ts:834
    deserializeTop deserializer.ts:856
    fromCrossJSON index.ts:189
    onMessage serverFnFetcher.ts:289
    drain serverFnFetcher.ts:391
    processFramedResponse serverFnFetcher.js:226
    getResponse serverFnFetcher.ts:287
    serverFnFetcher serverFnFetcher.ts:167
    clientFn createClientRpc.ts:12
    client createServerFn.ts:921
    callNextMiddleware createServerFn.ts:313
    executeMiddleware createServerFn.ts:353
    handler createServerFn.ts:150
    onClick index.tsx:17
    React 13
    <anonymous> client.tsx:6
    startTransition React
    <anonymous> client.tsx:5
[__root.tsx:66:14](http://localhost:3000/src/routes/__root.tsx)
Invalid JSON: {"t":34,"i":5,"f":{"t":2,"s":1}}
 Error: Seroval caught an error during the deserialization process.

Error
Malformed node type "34".

- For more information, please check the "cause" property of this error.
- If you believe this is an error in Seroval, please submit an issue at https://github.com/lxsmnsyc/seroval/issues/new
    SerovalError errors.ts:51
    SerovalDeserializationError errors.ts:69
    deserializeTop deserializer.ts:858
    fromCrossJSON index.ts:189
    onMessage serverFnFetcher.ts:289
    drain serverFnFetcher.ts:391
    processFramedResponse serverFnFetcher.js:226
    getResponse serverFnFetcher.ts:287
    serverFnFetcher serverFnFetcher.ts:167
    clientFn createClientRpc.ts:12
    client createServerFn.ts:921
    callNextMiddleware createServerFn.ts:313
    executeMiddleware createServerFn.ts:353
    handler createServerFn.ts:150
    onClick index.tsx:17
    React 13
    <anonymous> client.tsx:6
    startTransition React
    <anonymous> client.tsx:5
Caused by: Error: Malformed node type "34".
    SerovalMalformedNodeError errors.ts:170
    validateNodeType deserializer.ts:368
    deserializeStreamReturn deserializer.ts:723
    deserialize deserializer.ts:838
    deserializeTop deserializer.ts:856
    fromCrossJSON index.ts:189
    onMessage serverFnFetcher.ts:289
    drain serverFnFetcher.ts:391
    processFramedResponse serverFnFetcher.js:226
    getResponse serverFnFetcher.ts:287
    serverFnFetcher serverFnFetcher.ts:167
    clientFn createClientRpc.ts:12
    client createServerFn.ts:921
    callNextMiddleware createServerFn.ts:313
    executeMiddleware createServerFn.ts:353
    handler createServerFn.ts:150
    onClick index.tsx:17
    React 13
    <anonymous> client.tsx:6
    startTransition React
    <anonymous> client.tsx:5

Complete minimal reproducer

https://github.com/Zuruuh/start-async-generator-repro

Steps to Reproduce the Bug

1. Go to http://localhost:3000
2. Open the console devtools
3. Press the Test button

Expected behavior

I expect the deserialization to complete successfully so I can stream the response of my server function

Screenshots or Videos

No response

Platform

• Router / Start Version: latset
• OS: MacOS
• Browser: Firefox, Brave
• Browser Version: 150.x, 1.89.132
• Bundler: vite
• Bundler Version: 8.0.x

Additional context

I think I got this to work a few weeks ago and it might be possible that a recent update broke it