With sudo or not when to execute "composer require" command? - composer-php

Question

Normally , it run across issue Do not run Composer as root/super user! See https://getcomposer.org/root for details when to execute sudo composer require somePackage.
Here is my record for installing swiftmailer.
Firstly to execute composer require somePackage without sudo.
debian9#machine:~$ composer require "swiftmailer/swiftmailer:^6.0"
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Installation failed, reverting ./composer.json to its original content.
[RuntimeException]
/home/debian9/vendor/doctrine/lexer does not exist and could not be created
.
require [--dev] [--prefer-source] [--prefer-dist] [--no-progress] [--no-update] [--no-scripts] [--update-no-dev] [--update-with-dependencies] [--ignore-platform-reqs] [--prefer-stable] [--prefer-lowest] [--sort-packages] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--] [<packages>]...
Let's try with sudo.
debian9#machine:~$ sudo composer require "swiftmailer/swiftmailer:^6.0"
Do not run Composer as root/super user! See https://getcomposer.org/root for details
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
- Installing doctrine/lexer (v1.0.1)
Downloading: 100%
- Installing egulias/email-validator (2.1.6)
Downloading: 100%
- Installing swiftmailer/swiftmailer (v6.1.3)
Downloading: 100%
egulias/email-validator suggests installing ext-intl (PHP Internationalization Libraries are required to use the SpoofChecking validation)
swiftmailer/swiftmailer suggests installing ext-intl (Needed to support internationalized email addresses)
swiftmailer/swiftmailer suggests installing true/punycode (Needed to support internationalized email addresses, if ext-intl is not installed)
Writing lock file
Generating autoload files
I am confused that without sudo ,swiftmailer can't be installed,with sudo ,an error occur Do not run Composer as root/super user!.

Answer 1

You've probably run Composer with sudo in the past. This has left some of the directories under vendor/ owned by root, preventing you from using Composer normally.
Change ownership on the entire vendor directory to your shell user, or delete the directory entirely. (You will need to do this as root.) Once you have done so, you should be able to use Composer normally.