なにが起こったか

Centos7に運用中のLaravelプロジェクトをクローンしてcomposer installしたらコケた。

$ composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for php-di/invoker 2.1.0 -> satisfiable by php-di/invoker[2.1.0].
    - php-di/invoker 2.1.0 requires php >=7.3 -> your PHP version (7.2.28) does not satisfy that requirement.
  Problem 2
    - Installation request for doctrine/dbal 2.11.1 -> satisfiable by doctrine/dbal[2.11.1].
    - doctrine/dbal 2.11.1 requires php ^7.3 -> your PHP version (7.2.28) does not satisfy that requirement.
  Problem 3
    - php-di/invoker 2.1.0 requires php >=7.3 -> your PHP version (7.2.28) does not satisfy that requirement.
    - mnapoli/silly 1.7.2 requires php-di/invoker ~2.0 -> satisfiable by php-di/invoker[2.1.0].
    - Installation request for mnapoli/silly 1.7.2 -> satisfiable by mnapoli/silly[1.7.2].

解決方法

エラーメッセージを見る限りPHPのバージョン問題だったので、PHPを7.2から7.4へアップデートした。
※正確にはPHP7.3以上を求められていた。

PHP7.4インストール

$ sudo yum install -y --enablerepo=remi-php74 php which
み込んだプラグイン:fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: ty1.mirror.newmediaexpress.com
 * epel: nrt.edge.kernel.org
 * extras: ty1.mirror.newmediaexpress.com
 * remi-php74: ftp.riken.jp
 * remi-safe: ftp.riken.jp
 * updates: ty1.mirror.newmediaexpress.com
...

PHPインストール確認

$ php -v
PHP 7.4.13 (cli) (built: Nov 24 2020 10:03:34) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v7.4.13, Copyright (c), by Zend Technologies
    with Xdebug v2.9.8, Copyright (c) 2002-2020, by Derick Rethans