Laravel Sail: Your Composer dependencies require a PHP version “>= 8.0.0”. You are running 7.4.x

I was trying to create a new Laravel project when this error appeared in my terminal. The PHP process inside the container keeps restarting because of this error.

How to reproduce?

$ curl -s "https://laravel.build/example-app?with=mysql,redis,mailhog" | bash
...
$ cd example-app
example-app$ ./vendor/bin/sail up

example-app.test-1  | usermod: no changes
example-app.test-1  | 2021-10-29 13:37:29,645 INFO Set uid to user 0 succeeded
example-app.test-1  | 2021-10-29 13:37:29,646 INFO supervisord started with pid 9
example-app.test-1  | 2021-10-29 13:37:30,649 INFO spawned: 'php' with pid 11
example-app.test-1  | Composer detected issues in your platform:
example-app.test-1  | 
example-app.test-1  | Your Composer dependencies require a PHP version ">= 8.0.0". You are running 7.4.20.2021-10-29 13:37:31,672 INFO success: php entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
example-app.test-1  | 2021-10-29 13:37:31,672 INFO exited: php (exit status 104; not expected)
example-app.test-1  | 2021-10-29 13:37:32,675 INFO spawned: 'php' with pid 12
example-app.test-1  | Your Composer dependencies require a PHP version ">= 8.0.0". You are running 7.4.20.2021-10-29 13:37:33,695 INFO success: php entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
example-app.test-1  | 2021-10-29 13:37:33,696 INFO exited: php (exit status 104; not expected)
example-app.test-1  | 2021-10-29 13:37:34,699 INFO spawned: 'php' with pid 13
example-app.test-1  | Composer detected issues in your platform:
example-app.test-1  | 
example-app.test-1  | Your Composer dependencies require a PHP version ">= 8.0.0". You are running 7.4.20.2021-10-29 13:37:35,720 INFO success: php entered RUNNING state, process has stayed up for > than 1 seconds (startsecs)
example-app.test-1  | 2021-10-29 13:37:35,721 INFO exited: php (exit status 104; not expected)
example-app.test-1  | 2021-10-29 13:37:36,723 INFO spawned: 'php' with pid 14
... and many more

Solution

Open composer.json using your favorite text editor and apply the following changes:

"php": "^7.3|^8.0",

Make sure Sail is still running despite the error.

example-app$ ./vendor/bin/sail bash
(container)$ composer update
(container)$ php artisan # this should work now

p/s: when I tried to reproduce this bug again (by reverting the changes above), the error did not appear anymore, but I’m still gonna publish this article because I think it might help somebody in the future ¯\_(ツ)_/¯