Laravelインストーラを使ってインストールした時にエラーが起きた場合の対処法です。

問題

$ laravel new project-name
Crafting application...
PHP Fatal error:  Uncaught Error: Call to undefined method Symfony\Component\Process\Process::fromShellCommandline() in /Users/ucan/.composer/vendor/laravel/installer/src/NewCommand.php:84
Stack trace:
#0 /Users/ucan/.composer/vendor/symfony/console/Command/Command.php(251): Laravel\Installer\Console\NewCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#1 /Users/ucan/.composer/vendor/symfony/console/Application.php(886): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#2 /Users/ucan/.composer/vendor/symfony/console/Application.php(262): Symfony\Component\Console\Application->doRunCommand(Object(Laravel\Installer\Console\NewCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#3 /Users/ucan/.composer/vendor/symfony/console/Application.php(145): Symfony\Component\Console\Application->doRun in /Users/ucan/.composer/vendor/laravel/installer/src/NewCommand.php on line 84

Fatal error: Uncaught Error: Call to undefined method Symfony\Component\Process\Process::fromShellCommandline() in /Users/ucan/.composer/vendor/laravel/installer/src/NewCommand.php:84
Stack trace:
#0 /Users/ucan/.composer/vendor/symfony/console/Command/Command.php(251): Laravel\Installer\Console\NewCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#1 /Users/ucan/.composer/vendor/symfony/console/Application.php(886): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#2 /Users/ucan/.composer/vendor/symfony/console/Application.php(262): Symfony\Component\Console\Application->doRunCommand(Object(Laravel\Installer\Console\NewCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#3 /Users/ucan/.composer/vendor/symfony/console/Application.php(145): Symfony\Component\Console\Application->doRun in /Users/ucan/.composer/vendor/laravel/installer/src/NewCommand.php on line 84

Laravelインストーラが古いので更新しましょう...😅

対策

$ composer global update

ディレクトリは作成されてるので削除してやり直しましょう。

$ rm -rf project-name
$ laravel new project-name
$ php artisan -V
Laravel Framework 7.10.3

バージョン表示できたらokです。

参考

https://laracasts.com/discuss/channels/laravel/laravel-new-app-not-working-after-upgrading-laravel-installer