Next.js: next fails to properly kill server when found change in next.config.js

[yhaskell]

Bug report

Describe the bug

When user changes next.config.js, next runner notices changes, and tells about that:

> Ready on http://localhost:3000

> Found a change in next.config.js, restarting the server...

Then it recompiles everything successfully, but after that fails out of next with error:

Port 3000 is already in use.
Use `npm run start -- -p <some other port>`.
error Command failed with exit code 1.

In output of ps I still see node running with next-dev.

To Reproduce

1. Create empty project with next.js
2. Add next.config.js (correct one)
3. npx next
4. Change next.config.js
5. See next failing and next-dev still running in background

Expected behavior

Server restarts and proceeds to work

System information

• OS: Mac OS X 10.14
• Browser: n/a
• Version of Next.js: next.js v7.0.2
• Node version: 10.12.0

[yhaskell]

P.S. Tried on Debian 9.5, does not reproduce.

[timneutkens]

This was probably fixed already 👍

[kmiyashiro]

I'm also seeing this on Mac OS 10.14, next.js 7.0.2, node 11.5

[fnpen]

I'm also seeing this on Mac OS 10.14, next.js 7.0.2, node 11.5

"next": "^7.0.2", - Each time. The Same :-(

[andrewmartin]

Same setup as @fnpen, seeing this issue.

[timneutkens]

Feel free to create a PR to fix this.

[teleginzhenya]

Node v11.1.0
Next v8.0.0-canary.17

Works fine 👍

 DONE  Compiled successfully in 1346ms                                                                      2:44:58 PM

> Ready on http://localhost:3000

> Found a change in next.config.js, restarting the server...
✔ success server compiled in 128ms
✔ success client compiled in 847ms


 DONE  Compiled successfully in 1448ms

[vdiaz1130]

I can confirm this is an issue.

Already up-to port 3003... If you leave it long enough it would refresh and start up again but you will not be able to kill the process with ctrl + c. Hitting ctrl + c seems like it kills the process but you will need to specify a new port.

However, in spite of the 'port is already in use error', after a few seconds, it will start up on the specified port.

[timneutkens]

We've changed the way the process works, it's currently out on the canary channel. We give a warning saying to restart the server as we can't restart automatically since it's now a single process. This also ties into the custom server which already didn't have this behavior.

https://github.com/zeit/next.js/blob/canary/packages/next/bin/next.ts#L83-L92