fix: avoid dev-server crash when ws proxy error

[rawbin-]

Description

Fix #12664

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the PR Title Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

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[ArnaudBarre]

While this PR seems to make sense, a small reproduction of the error would really help be sure this block is needed and the error was not fixed by previous commit as pointed in the linked issue

[rawbin-]

1. install docker

brew install --cask docker

2. run grafana docker

docker run -d -p 3000:3000 --name grafana grafana/grafana-oss:9.2.6

3. change grafana docker for grafana prefix

docker cp grafana:/etc/grafana/grafana.ini ./
## change config grafana.ini to the following and enable the two config
root_url = %(protocol)s://%(domain)s:%(http_port)s/grafana
serve_from_sub_path = true
## change config end
cp ./grafana.ini grafana:/etc/grafana/grafana.ini
docker restart grafana

4. create vite demo

npx create-vue vite-repo

5. set proxy to grafana

  server:{
    proxy:{
        '^/grafana': {
            changeOrigin: true,
            ws: true,
            target: 'http://localhost:3000/',
        }
    }
  }

6. run the demo and navigate to /grafana we can see the crash still on 4.3.5

or run the demo navigate to /grafana or /test

[patak-dev]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI: Open

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

[ArnaudBarre]

Is the ecosystem CI running with an old main base maybe?
Tested locally, can reproduce and patching node_module with this code correctly fix the crash.

[patak-dev]

Yes, the PR is using a month-old state of main. Let's merge this one 👍🏼