[React 19] form.requestSubmit() resets input value/defaultValue after transition

[andrematulionis-nomad]

Summary

When form is submitted through form.requestSubmit() the input displays the older value instead of the current state.

Peek.2024-07-30.12-45.mp4

I tested using value and defaultValue props, and both leads to the same issue. When the form is submitted through <button type="submit"> it works fine, and form.submit() also has no problem, the issue is only using form.requestSubmit().
I suspect that this is an issue in react-dom reconciler. The state is correct in the log, but the actual <input> value is not.
In the repro there is an useOptimistic but this happens without it too.

Repro: https://stackblitz.com/edit/vitejs-vite-i9sbuj?file=src%2FApp.tsx

Version:

"react": "^19.0.0-rc-941e1b4a-20240729",
"react-dom": "^19.0.0-rc-941e1b4a-20240729"

To make sure this wasn't reported, I tried searching for transition state reset, useActionState and requestSubmit, didn't find anything related.

[eps1lon]

This is intended behavior when using Form Actions to match the default HTML behavior which is also the behavior you'd get before hydration.

Closing as a duplicate of #29034