env variables not expanded in .env file

[FezVrasta]

Describe the bug

We recently migrated from Create React App to Vite and we are encountering issues with the way dotenv and dotenv-expand is configured.

Our .env file used to look like this:

REACT_APP_DEPLOY_ENV=$DEPLOY_ENV

This allowed our app to read the global DEPLOY_ENV variable as REACT_APP_DEPLOY_ENV.

We changed it to:

VITE_DEPLOY_ENV=$DEPLOY_ENV

But the VITE_ prefixed variable is never defined.

I don't think this is intended, as dotenv-expand should have access to the environment variables in order to work, but right now it doesn't seem to work.

Note that this example doesn't work either:

VITE_NOT_WORKING=$VITE_WORKING

In this last example import.meta.env.VITE_WORKING will work but import.meta.env.VITE_NOT_WORKING will be empty.

Reproduction

https://stackblitz.com/edit/vitejs-vite-6jvttl?file=main.js

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (4) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    vite: ^3.1.0 => 3.1.0 

Used Package Manager

npm

Logs

No response

Validations

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

[sapphi-red]

Duplicate of #6626

[FezVrasta]

Oh right, thanks!