Composer autoload error after adding package to new Laravel project

[michaelklopf]

Hey,

I setup a new Laravel 10 project, created some classes and wanted to test this with Pest. I required the package and get the following error, when running the ./vendor/bin/pest command:

Fatal error: Cannot declare class ComposerAutoloaderInit[uuid], 
because the name is already in use in [project_path]/vendor/composer/autoload_real.php on line 5.

I have seen this error a couple of times by now (in different projects) and it drives me crazy. I have found no solution how to solve that problem consistently. Usually you remove the vendor folder and the lock file and do a composer update. Probably because this is an error in the packages, but it didn't work here.

I wonder why no one else is hit by that. Can't find anything to help me debug that. PHPUnit is running fine btw.

The pest version in the lock file is v2.6.0. v2.5.0 has the same problem.