[yangshun]

Summary

Brings useForm and useIslandForm in Vue, Svelte and Solid in line with React, fixing two bugs in how they handle a submit that is still in flight.

Why the adapters differ

All four adapters used to share these bugs. #738 fixed them in React only, so React has guarded concurrent submits and kept submitted values since then, while Vue, Svelte and Solid have not.

The issues

1. An older submit could still change the form when a newer one was running (3c9ddc5ae)

The forms tracked submits with flags and did not record which one was latest.

• Page forms: a second submit aborts the first through the router, and the first's finally then set pending = false while the second was still running. A submit button disabled by pending became clickable again mid-request. An older submit that still completed could also apply its errors, success state and defaults.
• Island forms: nothing aborts the older request, so its response could overwrite a newer result, clear pending, reload the page or redirect, whichever finished first.

2. Edits made during a submit counted as saved (e4ca5a713)

On success, the forms saved their values as of the response rather than as of the submit.

• hasChanges read false, and reset() restored text that was never sent.
• resetOnSuccess wiped anything typed while the request was in flight.
• Page forms sent a shallow copy, so nested values were shared with the live form.

The fix

• Each form counts its submits with requestId and latestRequestId, the same names React's island form uses. Only the latest submit updates state, reloads or redirects. An older submit's real failure still rejects its own promise.
• Each form takes a deep copy when submit starts, sends it and saves it as the new defaults.
• resetOnSuccess only clears the data if it has not changed since submit.
• The hasChanges and resetOnSuccess docs now cover edits made during a submit. Most of that diff is the formatter repadding the table.

Behaviour that still differs from React

• Two page-form submits: React's useActionState queues them, while Vue, Svelte and Solid abort the first and keep the latest. This PR keeps that difference. The server may still have processed an aborted request.
• resetOnSuccess edit check: these adapters compare values, because their form data is mutated in place, while React compares object identity. Typing something and changing it back counts as unchanged here.

Test plan

New tests cover both finishing orders, aborts, older failures, in-flight edits and resetOnSuccess, based on the React test added in #738. Solid's are in a new file because they need its client runtime. They assert through reset() rather than hasChanges, because createStore and createMemo do not track each other under those test mocks.

• All new tests that assert the bugs failed before their fix (18 for overlap, 9 for in-flight edits)
• Form tests for all four adapters pass (72)
• Vue, Svelte and Solid typechecks, format and lint pass
• vp run check passes (33/33)
• CI passes on e4ca5a713
• Local browser tests on the rebased code. vp test run had 16,106 tests pass and 41 fail, every failure being browserType.launch: Executable doesn't exist, because this machine lacks the Chromium build Playwright 1.65 expects

🤖 Generated with Claude Code

[yangshun]

Solid gets a new test file because these tests need its client runtime, since createMemo only evaluates once on the server runtime that use-form.test.ts uses. vi.mock is file-wide, so adding them there would have switched the existing tests too.

[cpojer]

Starting to feel like all the UI frameworks are the same.