useSubmission input is empty during ssr depending on FormData size

[katywings]

Describe the bug

If you natively (disabled js) submit a router-action based form with large form values, the form data will be in the server-function argument as expected, but useSubmission().input is empty during ssr.

Your Example Website or App

Stackblitz had a wasm problem, Repro ZIP is in "Additional context"

Steps to Reproduce the Bug or Issue

1. Add a form with a router+server-fn based action and a textarea
2. Output useSubmission().input in the JSX
3. console.log the form data in the server-fn
4. Open the browser + disable js in devtools
5. Enter a very large text in the textarea and submit
6. The server function logs the form data, but the submission input will be empty

Expected behavior

useSubmission().input during ssr should by consistent with the server-fn arguments, even if the submitted FormData has large values.

Screenshots or Videos

https://github.com/user-attachments/assets/03730595-5338-4add-a31b-f04d0eef6204

Platform

• OS: Linux
• Browser: Firefox

Additional context

Reproduction (based on SolidStart bare): start-empty-submission-large-values.zip