fix(server): remove restart guard on restart

[bluwy]

Description

fix #13735

On server restart, we assign the _restartPromise of the old server to the new server to prevent the new server's restart() from working (to prevent chaos like port collision, proper server listen/teardown). This was done in #7004 (the guard)

However, #13262 uses _restartPromise for another purpose -- throw on outdated request. That means there's a short interim during server listen that _restartPromise exist as a guard, but the server isn't actually outdated.

#13735 showed an edge case in SvelteKit where it calls ssrLoadModule in this interim causing it to falsely error.

This PR removes that guard as I don't think it's useful? On initial server startup we aren't guarding it either.

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI: Open

suite	result
analogjs	✅ success
astro	✅ success
histoire	❌ failure
iles	❌ failure
ladle	✅ success
laravel	✅ success
marko	✅ success
nuxt	✅ success
nx	✅ success
previewjs	✅ success
qwik	✅ success
rakkas	✅ success
sveltekit	✅ success
unocss	✅ success
vite-plugin-pwa	✅ success
vite-plugin-ssr	✅ success
vite-plugin-react	✅ success
vite-plugin-react-pages	✅ success
vite-plugin-react-swc	✅ success
vite-plugin-svelte	✅ success
vite-plugin-vue	✅ success
vite-setup-catalogue	✅ success
vitepress	✅ success
vitest	✅ success

[patak-dev]

Oh, I didn't see this one. I think it is ok to merge this PR to fix the edge case after #13262. We may still want a init guard that prevents restarts while the server is starting (so it also works on server starts), but that could be done in another PR if we think it is justified.

[RIP21]

BTW. This or something else may trigger a weird restart loop in watch mode.
One of my colleagues has issues that it goes into a cycle of restarts due to ".env" files change (they're not changing).

For me, it happens too, but stops after 3-5 retries.

[RIP21]

Ok, it gets into that state for me too, but in different copy of the repo.

Very weird behaviour :/

[RIP21]

Reverting Vite version all the way to 4.3.9 prevents it from happening. It just gets into it 2-3 times and then stops. Next time I run dev it's not getting into this state at all.
I also noticed that I'm getting some weird vite.config.js.timestamp.js or so file and it appears and disappears sometimes (maybe this is what causing it too?).

[bluwy]

If it's happening in 4.3.9 too, it's likely not quite related to this PR. I'd suggest removing your Vite plugins one by one to figure out which is touching the env files or vite config files that causes the restart. Otherwise a quick workaround for now is to configure server.watch.ignored: ['**/vite.config.ts', '**/.env.*'] to skip Vite detecting their changes.

[RIP21]

@bluwy probably. Maybe it's a Sentry plugin. I'll look into it later. But for now, somehow 4.3.9 still fixed it for everyone.

Thanks for the hint 🫡

[RIP21]

Yeah, it's @sentry/vite-plugin to blame. Commenting it out solves the problem.
https://github.com/getsentry/sentry-javascript-bundler-plugins/tree/main/packages/vite-plugin