Environment

• Operating System: macOS (Darwin)
• Package Manager: [email protected]
• Nuxt Version: 4.4.6
• Nitro Version: 2.13.4
• Vite Version: 7.3.3
• @vitejs/devtools: 0.1.24

Reproduction

1. Create a Nuxt 4.4.x project inside a monorepo setup.
2. Install nuxt and add @vitejs/devtools (e.g. ^0.1.24) as a devDependency.
3. Run bun install. Verify that [email protected] is resolved and hoisted to the parent/root node_modules/h3.
4. Create a server API route (e.g. server/api/[...].ts) to proxy incoming requests:

export default defineEventHandler(async (event) => {
  const targetUrl = `http://127.0.0.1:8080${event.path}`
  
  return proxyRequest(event, targetUrl, {
    fetchOptions: {
      redirect: 'manual',
    }
  })
})

Describe the bug

In a monorepo setup (or when running installations that hoist devDependencies to root node_modules), if a dependency like @vitejs/devtools pulls h3 version 2.0.1-rc.22 (pre-release version), it gets hoisted to the top-level node_modules/h3.

During building/development, Nitro's compiler resolves auto-imported utilities like proxyRequest from h3 v2.x (which is found at the root/top-level node_modules). However, Nitro's internal runtime is running on [email protected] and instantiates the request event object using the 1.x branch structure.

Because [email protected] introduces signature changes and expects event.req.headers to be a Web API Headers instance supporting .entries(), calling proxyRequest(event, ...) throws a runtime error:
TypeError: event.req.headers.entries is not a function or its return value is not iterable

Nitro should enforce that auto-imported runtime utilities like proxyRequest are resolved from the pinned h3 version matching Nitro's own runtime version (1.x at this moment) instead of allowing hoisted/external packages to hijack the imports.

Additional context

No response

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