Vite 5.1.x does not watch on vite build with outDir: ''

[susnux]

Describe the bug

When using vite for building like vite --mode development build --watch, vite terminates (no failure) after building the files.
So it does not watch anymore for file changes.
I tested this with different vite versions:

• 5.0.12 was the last good one ✅
• 5.1.{0,1,2} all three are broken ❌

The problem seems to only appear when setting outDir: '' which is required for us as the folder structure of our projects is like:

• /src (input files)
• /js (output files)
• /css (output css files)
• /img (output images files)

Reproduction

https://stackblitz.com/edit/vitejs-vite-z4xoqc?file=vite.config.js

Steps to reproduce

Run npm i && npm run watch

System Info

System:
    OS: Linux 6.7 openSUSE Tumbleweed 20240207
    CPU: (12) x64 AMD Ryzen 5 5500U with Radeon Graphics
    Memory: 2.28 GB / 14.98 GB
    Container: Yes
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.10.0 - /usr/bin/node
    Yarn: 1.22.21 - /usr/bin/yarn
    npm: 10.2.3 - /usr/bin/npm
  Browsers:
    Chromium: 120.0.6099.224
  npmPackages:
    vite: ^5.1.3 => 5.1.3

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-z4xoqc (Open reproduction)