Composer updateがエラーになる原因が知りたい。

Question

提示コードですがError code 部のエラーが出てcomposer updateを実行できません。参考サイトを参考にバージョンをアップデートして
バージョンを合わせたのですがこれは何が原因なのでしょうか？

参考サイト：　https://www.softel.co.jp/blogs/tech/archives/3826
参考サイト：　https://tutorialcrawler.com/ubuntu-debian/ubuntu20-04%E3%81%ABphp8%E3%82%92%E3%82%A4%E3%83%B3%E3%82%B9%E3%83%88%E3%83%BC%E3%83%AB%E3%81%99%E3%82%8B%E6%96%B9%E6%B3%95/

composer.json

{
    "config": 
    {
        "platform-check": false,
        "platform": {
            "php": "8.1.3"
        }
    },

    "require": 
    {
        "michelf/php-markdown": "1.9.1",
        "ramsey/uuid": "4.2.3",
        "laravel/laravel": "9.1.1"
    }
}

Error code

Your requirements could not be resolved to an installable set of packages.

php version

shigurechan@shigurechan-System-Product-Name:~/prg/html$ php -v
PHP 8.1.3 (cli) (built: Feb 21 2022 14:48:42) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.3, Copyright (c) Zend Technologies
    with Zend OPcache v8.1.3, Copyright (c), by Zend Technologies

Console

shigurechan@shigurechan-System-Product-Name:~/prg/html$ composer update
Composer is operating significantly slower than normal because you do not have the PHP curl extension enabled.
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - tijsverkoyen/css-to-inline-styles 2.2.2 requires php ^5.5 || ^7.0 -> your php version (8.1.3; overridden via config.platform, same as actual) does not satisfy that requirement.
    - tijsverkoyen/css-to-inline-styles[2.2.3, ..., 2.2.4] require ext-dom * -> it is missing from your system. Install or enable PHP's dom extension.
    - laravel/laravel v9.1.1 requires laravel/framework ^9.2 -> satisfiable by laravel/framework[v9.2.0, ..., v9.4.1].
    - laravel/framework[v9.2.0, ..., v9.4.1] require tijsverkoyen/css-to-inline-styles ^2.2.2 -> satisfiable by tijsverkoyen/css-to-inline-styles[2.2.2, 2.2.3, 2.2.4].
    - Root composer.json requires laravel/laravel 9.1.1 -> satisfiable by laravel/laravel[v9.1.1].

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/20-calendar.ini
    - /etc/php/8.1/cli/conf.d/20-ctype.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-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
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-dom` to temporarily ignore these required extensions.

Comments

[m.ts10806]

エラーに書いてあるので原因が何かと言われても、エラーを読めとしか

Answer 1

ここに書かれてる

tijsverkoyen/css-to-inline-styles 2.2.2 requires php ^5.5 || ^7.0 -> your php version (8.1.3; overridden via config.platform, same as actual) does not satisfy that requirement.

Comments

[退会済みユーザー]

すいませんこれは何をしろうという意味なのでしょうか？cssのバージョンがどうたら言われているのはわかりますが

[phper.k]

直訳すると
css-to-inline-styles 2.2.2 というライブラリは、PHP 5.5 または PHP7.0 が必要
あなたの PHP は 8.1.3 ですと書かれています。

[phper.k]

あと、
tijsverkoyen/css-to-inline-styles[2.2.3, ..., 2.2.4] require ext-dom * -> it is missing from your system. Install or enable PHP's dom extension.

これも問題ですね