SSR build will always be run when specified builder.buildApp

[Justinidlerz]

Describe the bug

Reproduction

https://stackblitz.com/edit/vitejs-rolldown-vite-bxlhxyk3

Steps to reproduce

Add builder.buildApp into config

import { defineConfig } from 'vite';

export default defineConfig({
  build: {
    lib: {
      entry: './src/counter.js',
      name: 'counter',
    },
  },
  builder: {
    async buildApp() {
      console.log(123);
    },
  },
});

run vite build

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: 20.19.1 - /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:
    rolldown-vite:  7.2.2

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs and the Rolldown-related guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.