Describe the bug

Hello! I have a pretty basic vite.config.ts. Main area of interest is this:

  build: {
    rollupOptions: {
      input: {
        "my-app": resolve(__dirname, "index.html"),
      },
    }
  }

With Vite 2.x, it would produce this output:

dist/index.html
dist/assets/my-app.<hash>.css
dist/assets/my-app.<hash>.js

After upgrading to Vite 3 it changed to this:

dist/index.html
dist/assets/index.<hash>.css
dist/assets/my-app.<hash>.js

Is that change intentional? Is there an easy way to get this behavior back, beyond adding a hack in assetFileNames?

Thanks!

Reproduction

https://stackblitz.com/edit/vitejs-vite-r2ykgd?file=vite.config.js

System Info

System:
    OS: Windows 10 10.0.19044
    CPU: (4) x64 Intel(R) Core(TM) i7-7600U CPU @ 2.80GHz
    Memory: 5.73 GB / 23.84 GB
  Binaries:
    Node: 16.14.2 - C:\Program Files\nodejs\node.EXE     
    npm: 8.5.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 104.0.5112.102
    Edge: Spartan (44.19041.1266.0), Chromium (104.0.1293.63)

Used Package Manager

npm

Logs

No response

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• The provided reproduction is a minimal reproducible example of the bug.