Describe the bug

When a file is generated by a virtual file plugin such as https://github.com/patak-dev/vite-plugin-virtual, the corresponding module ID may look like /@virtual:vite-plugin-virtual/some/path/to/file.

When the HTML entry point specified for vite build is provided by such a virtual file plugin, its content is correctly loaded, but bundling fails because shortEmitName looks like "../../../../@virtual:vite-plugin-virtual/Users/fwouts/dev/vite-virtual-html/index.html":

✓ 6 modules transformed.
rendering chunks (1)...[vite:build-html] The "fileName" or "name" properties of emitted files must be strings that are neither absolute nor relative paths, received "../../../../@virtual:vite-plugin-virtual/Users/fwouts/dev/vite-virtual-html/index.html".
error during build:
Error: The "fileName" or "name" properties of emitted files must be strings that are neither absolute nor relative paths, received "../../../../@virtual:vite-plugin-virtual/Users/fwouts/dev/vite-virtual-html/index.html".
    at error (file:///Users/fwouts/dev/vite-virtual-html/node_modules/.pnpm/rollup@2.77.3/node_modules/rollup/dist/es/shared/rollup.js:1858:30)
    at FileEmitter.emitFile (file:///Users/fwouts/dev/vite-virtual-html/node_modules/.pnpm/rollup@2.77.3/node_modules/rollup/dist/es/shared/rollup.js:15472:24)
    at Object.generateBundle (file:///Users/fwouts/dev/vite-virtual-html/node_modules/.pnpm/vite@3.0.7/node_modules/vite/dist/node/chunks/dep-0f13c890.js:41599:22)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)

Overriding fileName with just the hardcoded value "index.html" here fixes it, although that's obviously not the right approach :)

Note 1: This appears related to #2321 but I don't think it's quite the same issue.

Note 2: In case you're wondering, one example where this would be useful is in Preview.js to allow users to generate a static, precompiled version of a particular component so they can share it around. For now, I can work around it by patching Vite on my end.

Note 3: I'd be happy to make a PR for this.

Reproduction

https://github.com/fwouts/vite-virtual-html

System Info

System:
    OS: macOS 12.5
    CPU: (8) arm64 Apple M1
    Memory: 87.44 MB / 8.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 16.15.0 - ~/.nvm/versions/node/v16.15.0/bin/node
    Yarn: 1.22.19 - ~/.yarn/bin/yarn
    npm: 8.9.0 - ~/.config/yarn/global/node_modules/.bin/npm
  Browsers:
    Chrome: 104.0.5112.79
    Firefox: 103.0.1
    Safari: 15.6
  npmPackages:
    vite: ^3.0.7 => 3.0.7

Used Package Manager

pnpm

Logs

No response

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