Dev server doesn't update overridden env var when doing an automatic reload.

[alexkreidler]

Describe the bug

I have a production API url and a local API URL I am trying to put into .env.local or .env.development. But after upgrading from vite 4.5.3 to 5.3.1, I noticed the dev server is not applying env vars correctly when doing an automatic reload.

Note that the frontend shows the correct value when killing the dev server and manually re-running from terminal

Reproduction

https://stackblitz.com/edit/vitejs-vite-y1ptn5?file=main.js,.env,.env.development&terminal=dev

Steps to reproduce

1. Put VITE_PUBLIC_API_URL=https://api.mysite.com in .env.
2. Add VITE_PUBLIC_API_URL=http:https://localhost:3100 in .env.local. After refreshing the frontend console.log(import.meta.env.VITE_PUBLIC_API_URL); shows the https://api.mysite.com value.
3. Do the same thing in .env.development, deleting .env.local, frontend still shows the old value

In StackBlitz you may have to delete .env.development, manually restart the server and then re-add it to reproduce.

System Info

System:
    OS: Linux 5.15 Ubuntu 22.04.4 LTS 22.04.4 LTS (Jammy Jellyfish)
    CPU: (16) x64 AMD Ryzen 7 3800X 8-Core Processor
    Memory: 11.82 GB / 15.56 GB
    Container: Yes
    Shell: 3.7.0 - /usr/bin/fish
  Binaries:
    Node: 18.14.0 - ~/.volta/tools/image/node/18.14.0/bin/node
    Yarn: 3.6.1 - ~/.volta/tools/image/yarn/1.22.19/bin/yarn
    npm: 9.3.1 - ~/.volta/tools/image/node/18.14.0/bin/npm
    pnpm: 8.6.5 - ~/.local/share/pnpm/pnpm
    bun: 0.5.8 - ~/.volta/bin/bun
    Watchman: 2023.12.04.00 - /home/linuxbrew/.linuxbrew/bin/watchman
  Browsers:
    Chrome: 123.0.6312.105
    Chromium: 126.0.6478.61

Used Package Manager

pnpm

Logs

3:41:26 AM [vite] .env.local changed, restarting server...
3:41:26 AM [vite] server restarted.
3:42:06 AM [vite] .env.development changed, restarting server...
3:42:06 AM [vite] server restarted.
3:42:16 AM [vite] .env changed, restarting server...

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-y1ptn5 (Open reproduction)