Client environment looks for index.html when mutating rolldownOptions.input #22033

Describe the bug

Client environment looks for index.html when mutating rolldownOptions.input. Mutating rollupOptions.input instead works.

Reproduction

https://stackblitz.com/edit/vitejs-vite-3p4vzscg?file=vite.config.ts&terminal=dev

Steps to reproduce

• npm install
• npm run build (works)
• comment the line with rollupOptions and uncomment the one with rolldownOptions
• npm run build (fails)

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 22.22.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    vite: ^8.0.1 => 8.0.2

Used Package Manager

npm

Logs

No response

Validations

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