Describe the bug

Using an .env file to define environment variables, static values are passed on and available in Vue as expected. Exposing existing env vars to Vue, however, does not work and produces empty values.

I've exposed the env var using the syntax from this comment.

STR:

• open reproduction
• start dev server with command PORT=4000 npm run dev

Expected:
PORT should be available from main.js and output 4000.

Actual:
PORT is an empty string.

Reproduction

https://stackblitz.com/edit/vitejs-vite-bxj6nd?devtoolsheight=33&file=.env

System Info

System:
    OS: macOS 11.6.1
    CPU: (12) x64 Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
    Memory: 1.36 GB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 16.13.2 - ~/.nix-profile/bin/node
    npm: 8.1.2 - ~/.nix-profile/bin/npm
  Browsers:
    Brave Browser: 97.1.34.81
    Safari: 15.2

Used Package Manager

npm

Logs

...
vite:config   env: {
vite:config     VITE_PORT: '',
vite:config     BASE_URL: '/',
vite:config     MODE: 'development',
vite:config     DEV: true,
vite:config     PROD: false
vite:config   },
...

Validations

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• The provided reproduction is a minimal reproducible example of the bug.