CSS iconfont unicode content converted with vite 4.3.*

[X-W-W]

Describe the bug

bundle and minify code with vite 4.3.*

original css code:
.icon-icon_cross2:before{content:"\ea0f"}
minified:
.icon-icon_cross2:before{content:""}

Using both esbuild and terser, all reproduced.

Casing problem:
Browser loads icon incorrect occasionally like this.

Temporarily Fix:
import cssnanoPlugin from 'cssnano';
build.cssMinify:false
css: {
postcss:{
plugins:[
cssnanoPlugin()
]
}
},

Reproduction

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

Steps to reproduce

npm run build
check dist/assets/index.css

then go to
vite.config.js
uncomment
// minify: false
run and check again
see the diffs

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: 16.20.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.4.2 - /usr/local/bin/npm
    pnpm: 8.6.3 - /usr/local/bin/pnpm
  npmPackages:
    vite: ^4.3.9 => 4.3.9

Used Package Manager

npm

Logs

No response

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.

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• vitejs-vite-xjsuvd (Open reproduction)

[sapphi-red]

This is expected.

In Vite 4.0, we changed the default charset to UTF-8 (#10753). But there was a bug that this was not applied to CSS (#12565); this fix landed in 4.3.0.
Since Vite 4, we expects users to setup the server configuration correctly (not to set other char set in Content-Type or <meta charset="">).

If you really want to convert the result to ASCII only, you can use esbuild.charset: 'ascii' option.