fix: use latest module graph in transform middleware

[bluwy]

Description

In SSR, when restarting the server, the transform middleware may still be referring to the old module graph causing a ERR_CLOSED_SERVER 504 error whenever we trying to fetch /@vite/client again. Even though Vite restarts the server with new middlewares, middlewareMode will always only use the original middlewares:

vite/playground/ssr/server.js

Lines 23 to 42 in fc24b07

	).createServer({
	root,
	logLevel: isTest ? 'error' : 'info',
	server: {
	middlewareMode: true,
	watch: {
	// During tests we edit the files too fast and sometimes chokidar
	// misses change events, so enforce polling for consistency
	usePolling: true,
	interval: 100,
	},
	hmr: {
	port: hmrPort,
	},
	},
	appType: 'custom',
	customLogger,
	})
	// use vite's connect instance as middleware
	app.use(vite.middlewares)

Additional context

I tested this in the ssr playground. You can start the server, open the page to see it work. Then update vite.config.js (a few times), then refresh the page. You'll see it failed to fetch the requests.

However, I can't seem to properly test this. The logs aren't predictable for some reason.

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

Oh, good catch! Incredible we only see this now.

I saw two more middlewares with the same problem for other config options, I'll send a separate PR.

This may be quite hard to find out for downstream projects, it is very low level but maybe we need to add this to the docs.