failed CSS preloads prevent loading dependencies

[danielroe]

Describe the bug

context: nuxt/nuxt#26972
Nuxt reproduction: https://stackblitz.com/edit/github-wg3yu6-bpadkv
Vite-only reproduction: https://stackblitz.com/edit/vitejs-vite-ce8f5t (you'll need to block CSS in your browser devtools)

If there is an issue loading a CSS dependency, you'll get this error:

Error: Unable to preload CSS for /assets/App-BBLnt7oG.css

However, the error that's thrown can't be worked around, even if e.preventDefault is called on it. If you register an error handler and try to suppress it, you'll get a different error instead:

// This changes the error but is still fatal
window.addEventListener('vite:preloadError', event => {
  event.preventDefault()
})
// TypeError: Cannot read properties of undefined (reading 'default')

I believe this is because the dep array is loaded with Promise.all, the other deps are blocked. I would suggest using Promise.allSettled.

The issue can occur in Google crawling a site, for example, if the CSS file references assets that are too large. See this search: https://www.google.com/search?q=%22Unable+to+preload+CSS%22+%22internal+server+error 🙈

Reproduction

https://stackblitz.com/edit/vitejs-vite-ce8f5t

Steps to reproduce

1. Do a yarn build, yarn preview
2. Go to your network tab and block *.css, then refresh the page

System Info

System:
    OS: macOS 14.6.1
    CPU: (8) arm64 Apple M2
    Memory: 53.66 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.5.0 - ~/.local/share/mise/installs/node/20.5.0/bin/node
    npm: 9.8.0 - ~/.local/share/mise/installs/node/20.5.0/bin/npm
    pnpm: 9.9.0 - ~/.local/share/mise/installs/node/20.5.0/bin/pnpm
    bun: 1.0.20 - ~/.bun/bin/bun
  Browsers:
    Chrome: 128.0.6613.120
    Safari: 17.6
  npmPackages:
    @vitejs/plugin-vue: 5.1.3 => 5.1.3

Used Package Manager

yarn

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• github-wg3yu6-bpadkv (Open reproduction)
• vitejs-vite-ce8f5t (Open reproduction)