The server-only environment variable can not be loaded if concurrentFeatures: true

[kjj6198]

What version of Next.js are you using?

latest (12.0.2)

What version of Node.js are you using?

14.16.0

What browser are you using?

Edge

What operating system are you using?

macOS

How are you deploying your application?

next dev

Describe the Bug

I'm using next.js environment variables example as an example. When I upgrade react to 18 (alpha) and enable the concurrentFeatures: true, the environment variables become undefined.

However, public variable can be read.

Expected Behavior

The blog post and docs seems not describing this behavior, so I expected the env variables should be loaded correctly.

To Reproduce

Repo can be found here.

1. define env variable in .env
2. enable concurrentFeatures: true
3. restart the dev server and observe the console output

[huozhi]

Looks like it's fixed in #31261, it works in latest next.js now could you please try again? 🙏

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.