`environments.ssr.build.emitAssets: true` not working when `builder.sharedConfigBuild: true`

[hi-ogawa]

Describe the bug

With a following config:

export default defineConfig({
  environments: {
    client: {
      build: {
        outDir: 'dist/client',
        rollupOptions: {
          input: './src/client.ts',
        },
      },
    },
    ssr: {
      build: {
        outDir: 'dist/ssr',
        emitAssets: true,
        rollupOptions: {
          input: './src/ssr.ts',
        },
      },
    },
  },
  builder: {
    sharedPlugins: true,
    sharedConfigBuild: true,
    async buildApp(builder) {
      console.log(
        '[client/emitAssets]',
        builder.environments.client.config.build.emitAssets
      ); // ==> true
      await builder.build(builder.environments.client);
      console.log(
        '[ssr/emitAssets]',
        builder.environments.ssr.config.build.emitAssets
      ); // ==> false
      await builder.build(builder.environments.ssr);
    },
  },
});

SSR build doesn't generate assets.

$ vite build
[client/emitAssets] true
vite v7.1.5 building for production...
✓ 2 modules transformed.
dist/client/assets/client-BaiKPFAq.css  1.20 kB │ gzip: 0.62 kB
dist/client/assets/client-CDmogNEK.js   0.02 kB │ gzip: 0.04 kB
✓ built in 128ms
[ssr/emitAssets] false
vite v7.1.5 building SSR bundle for production...
✓ 2 modules transformed.
dist/ssr/ssr.js  0.02 kB
✓ built in 26ms

Side note: Rsc plugin actually uses the same pattern and emitting css on rsc environment is working fine. But I noticed something weird when testing build.cssMinify: false and found that I cannot disable css minification on rsc environment.

Reproduction

https://stackblitz.com/edit/github-go4wdecj?file=vite.config.ts

Steps to reproduce

• open stackblitz

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:
    vite: ^7.1.2 => 7.1.5

Used Package Manager

pnpm

Logs

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:
vite: ^7.1.2 => 7.1.5

Validations

• Follow our Code of Conduct
• 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.
• 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.

[hi-ogawa]

It looks like emitAssets and cssMinify issues are different. cssMinify isn't working per environment probably because css plugin is reading top level config only. emitAssets isn't working specifically for environments.ssr.build.emitAssets option, which might be due to some config compat merging.

EDIT: cssMinify issue is moved to #20789.