Class ‘MagentoSetupApplication’ not found, after executing “git reset –hard”

I executed git reset --hard, but now I get:

PHP Fatal error:  Uncaught Error: Class 'MagentoSetupApplication' not found in /home/xy/vendor/magento/framework/Console/Cli.php:79
Stack trace:
#0 /home/xy/bin/magento(22): MagentoFrameworkConsoleCli->__construct('Magento CLI')
#1 {main}
  thrown in /home/xy/vendor/magento/framework/Console/Cli.php on line 79

I executed composer update in hope that this fixes it, but it doesnt. How can I fix?

Answer

It turned out that git reset --hard destroyed my setup folder for unknown reasons and not even git pull fixed it.

So I had to copy the folder from another project. Now it works.