fix(dev): close upgraded sockets and resolve on worker shutdown timeout

[danielroe]

🔗 Linked issue

nuxt/cli#1531
nuxt/cli#1532
resolves #4610

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

if a websocket connection to the dev worker is still open when the dev server closes, close() never resolves. the upstream nuxt/cli issue was that nuxt dev just hung for 15s (windows only, interestingly) until it hit a timeout:

 WARN  force closing dev worker...
▲  The dev server did not shut down within 15s: ... 1 open connection ... Exiting anyway.

w've worked around this in nuxt/cli#1532, but I think this is a bug worth fixing in nitro too (I've included a pure-nitro regression test that times out without the fix)

the issue is that:

1. in the worker, closeAllConnections doesn't cover upgraded sockets, so listener.close() waits as long as the websocket stays open and we never send the exit event
2. in #closeWorker, the graceful-shutdown timeout logs but never resolves

so, this PR destroys any upgraded sockets in shutdown() alongside closeAllConnections(), and resolves on timeout so we fall through to terminate() as intended

I think the reason existing tests didn't catch it was that we skip the graceful wait in test/CI environments. I've mocked std-env in the new test so we can avoid a regression in future

many thanks to @userquin for his helpful work finding the cause and opening issues in nuxt/cli + nitro ❤️

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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Project	Deployment	Actions	Updated
nitro.build	Ready	Preview	Sep 26, 2026 12:23pm UTC

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/nitropack@4671

commit: f3b2a50

[danielroe]

the failing test is also failing on v2

[userquin]

Nice, using nitropack at nuxt cli playground works.

Without this PR via pkg-pr-new (just the merged pr at nuxt cli, I guess it is the missing resolve at src/core/dev-server/worker.ts):

With this PR via pkg-pr-new with 3 tabs at /ws: