Environment variables not hot-reloaded after editing `.env` files

[clemyan]

Reproduction

1. Go to https://stackblitz.com/edit/remix-run-remix-semm1n?file=.env.local
2. See X = "1" is rendered on screen
3. Edit .env.local to X = 2 and save (Also works on .env, but StackBlitz does not persist .env files so using .env.local for demo)
4. The Vite server reloads, but still renders X = "1"
5. Manually stop and restart the server (npm run dev)
6. When the server starts up again, X = "2" is rendered

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (16) x64 Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz
    Memory: 5.94 GB / 31.87 GB
  Binaries:
    Node: 20.17.0 - C:\Program Files\nodejs\node.EXE      
    Yarn: 4.5.0 - C:\Program Files\nodejs\yarn.CMD        
    npm: 10.8.2 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (127.0.2651.74)
    Internet Explorer: 11.0.19041.4355
  npmPackages:
    @remix-run/dev: ^2.12.1 => 2.12.1 
    @remix-run/node: ^2.12.1 => 2.12.1 
    @remix-run/react: ^2.12.1 => 2.12.1 
    @remix-run/serve: ^2.12.1 => 2.12.1 
    vite: ^5.1.0 => 5.4.0

Used Package Manager

npm

Expected Behavior

In development (remix vite:dev), after editing .env files, the app re-renders or reloads with the new environment variables

Actual Behavior

The app sees the old variables, even after full page reloads.

[laishere]

Just tested. It seems for the variables already exist, they won't be reloaded.
However, when we set a new variable, it is loaded correctly.

After checking how vite handles .env, I found it's an expected behavior from package dotenv-expand.

1. Vite:
   https://github.com/vitejs/vite/blob/768a50f7ac668dbf876feef557d8c0f8ff32b8ff/packages/vite/src/node/env.ts#L55
2. dotenv-expand:
   https://github.com/motdotla/dotenv-expand/blob/ff7e2efd0d9925c7da82c167ae77d22a6c76e878/lib/main.js#L70-L71