ある日、composerコマンドを実行してLaravelプロジェクトを作ろうにも、エラーが出て作れない。

composer create-project --prefer-dist laravel/laravel testlaraveler1

を実行すると下記が得られる。

Creating a "laravel/laravel" project at "./testlaraveler1"
Info from https://repo.packagist.org: #StandWithUkraine
Installing laravel/laravel (v9.3.5)
  - Downloading laravel/laravel (v9.3.5)
  - Installing laravel/laravel (v9.3.5): Extracting archive
Created project in /home/akagi/Documents/programming/php/laravel_test03/testlaraveler1
> @php -r "file_exists('.env') || copy('.env.example', '.env');"
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - spatie/laravel-ignition[1.0.0, ..., 1.4.0] require ext-curl * -> it is missing from your system. Install or enable PHP's curl extension.
    - Root composer.json requires spatie/laravel-ignition ^1.0 -> satisfiable by spatie/laravel-ignition[1.0.0, ..., 1.4.0].

To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php/8.1/cli/php.ini
    - /etc/php/8.1/cli/conf.d/10-opcache.ini
    - /etc/php/8.1/cli/conf.d/10-pdo.ini
    - /etc/php/8.1/cli/conf.d/15-xml.ini
    - /etc/php/8.1/cli/conf.d/20-calendar.ini
    - /etc/php/8.1/cli/conf.d/20-ctype.ini
    - /etc/php/8.1/cli/conf.d/20-dom.ini
    - /etc/php/8.1/cli/conf.d/20-exif.ini
    - /etc/php/8.1/cli/conf.d/20-ffi.ini
    - /etc/php/8.1/cli/conf.d/20-fileinfo.ini
    - /etc/php/8.1/cli/conf.d/20-ftp.ini
    - /etc/php/8.1/cli/conf.d/20-gettext.ini
    - /etc/php/8.1/cli/conf.d/20-iconv.ini
    - /etc/php/8.1/cli/conf.d/20-phar.ini
    - /etc/php/8.1/cli/conf.d/20-posix.ini
    - /etc/php/8.1/cli/conf.d/20-readline.ini
    - /etc/php/8.1/cli/conf.d/20-shmop.ini
    - /etc/php/8.1/cli/conf.d/20-simplexml.ini
    - /etc/php/8.1/cli/conf.d/20-sockets.ini
    - /etc/php/8.1/cli/conf.d/20-sysvmsg.ini
    - /etc/php/8.1/cli/conf.d/20-sysvsem.ini
    - /etc/php/8.1/cli/conf.d/20-sysvshm.ini
    - /etc/php/8.1/cli/conf.d/20-tokenizer.ini
    - /etc/php/8.1/cli/conf.d/20-xmlreader.ini
    - /etc/php/8.1/cli/conf.d/20-xmlwriter.ini
    - /etc/php/8.1/cli/conf.d/20-xsl.ini
You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.
Alternatively, you can run Composer with `--ignore-platform-req=ext-curl` to temporarily ignore these required extensions.

ちなみにPHPは正常にインストールされている。

この状態を解決するには、php8.1-curlをインストールすれば良い。

sudo apt install php8.1-curl 

おそらく、PHPをバージョン8.1にする時、php8.1-curlのインストールがされていなかったようだ。下記サイトが役に立ったが、インストールするパッケージはphp8.1-curlで。

参照元:https://stackoverflow.com/questions/19335305/composer-install-error-requires-ext-curl-when-its-actually-enabled