PhpStorm: what are php-cs-fixer files and how to ignore them - phpstorm

Question

I keep getting "Multiple definitions exist for class..." warnings in PhpStorm, and upon inspection, I see these a bunch of these huge php-cs-fixer files (100K+ lines) with the comment "This file is part of PHP CS Fixer.".
I found that there are multiple copies of several other files named phploc, composer, php-scoper, etc., under vendor/library_name/tools/ in various libraries for some reason. They are all huge compiled files that PhpStorm detects.
I tried ignoring these files in PhpStorm one by one, and once re-indexing finishes, these files disappear, leading me to believe they're IDE-generated files. However, it makes no sense the IDE would generate them and in turn include them hinting code.
composer.json
{
"name": "magento/project-community-edition",
"description": "eCommerce Platform for Growth (Community Edition)",
"type": "project",
"license": [
"OSL-3.0",
"AFL-3.0"
],
"config": {
"preferred-install": "dist",
"sort-packages": true
},
"require": {
"magento/composer-root-update-plugin": "~1.0",
"magento/product-community-edition": "2.4.1"
},
"require-dev": {
"allure-framework/allure-phpunit": "~1.2.0",
"dealerdirect/phpcodesniffer-composer-installer": "^0.5.0",
"friendsofphp/php-cs-fixer": "~2.16.0",
"lusitanian/oauth": "~0.8.10",
"magento/magento-coding-standard": "*",
"magento/magento2-functional-testing-framework": "^3.0",
"pdepend/pdepend": "~2.7.1",
"phpcompatibility/php-compatibility": "^9.3",
"phpmd/phpmd": "^2.8.0",
"phpstan/phpstan": ">=0.12.3 <=0.12.23",
"phpunit/phpunit": "^9",
"sebastian/phpcpd": "~5.0.0",
"squizlabs/php_codesniffer": "~3.5.4"
},
"conflict": {
"gene/bluefoot": "*"
},
"autoload": {
"psr-4": {
"Magento\\Framework\\": "lib/internal/Magento/Framework/",
"Magento\\Setup\\": "setup/src/Magento/Setup/",
"Magento\\": "app/code/Magento/",
"Zend\\Mvc\\Controller\\": "setup/src/Zend/Mvc/Controller/"
},
"psr-0": {
"": [
"app/code/",
"generated/code/"
]
},
"files": [
"app/etc/NonComposerComponentRegistration.php",
"app/helper.php"
],
"exclude-from-classmap": [
"**/dev/**",
"**/update/**",
"**/Test/**"
]
},
"autoload-dev": {
"psr-4": {
"Magento\\Sniffs\\": "dev/tests/static/framework/Magento/Sniffs/",
"Magento\\Tools\\": "dev/tools/Magento/Tools/",
"Magento\\Tools\\Sanity\\": "dev/build/publication/sanity/Magento/Tools/Sanity/",
"Magento\\TestFramework\\Inspection\\": "dev/tests/static/framework/Magento/TestFramework/Inspection/",
"Magento\\TestFramework\\Utility\\": "dev/tests/static/framework/Magento/TestFramework/Utility/",
"Magento\\PhpStan\\": "dev/tests/static/framework/Magento/PhpStan/"
}
},
"version": "2.4.0",
"minimum-stability": "stable",
"repositories": [
{
"type": "composer",
"url": "https://repo.magento.com/"
}
],
"extra": {
"magento-force": "override"
}
}
PhpStorm ignored files (adding php-cs-fixer and phploc here somehow removed all/multiple copies from the vendor directories):

Answer 1

These files are in your vendor directory as you must have install your dependencies from sources, not distributions.
Let's use sebastian/code-unit as an example to see how it works:
the file obviously is in the repository: https://github.com/sebastianbergmann/code-unit/tree/1.0.8/tools
but excluded from being exported to distribution (the archive file you are actually downloading from GitHub when installing package): https://github.com/sebastianbergmann/code-unit/blob/1.0.8/.gitattributes#L6 - you can see that it's not present in file you download from https://github.com/sebastianbergmann/code-unit/releases/tag/1.0.8
So, you must have install your dependencies using composer install --prefer-source (or composer update --prefer-source as it's the other command with that option) and you want to use --prefer-dist or actually not using any of these flags as the latter is the default. You can find more information about it in official documentation: https://getcomposer.org/doc/03-cli.md#install-i
Remove your vendor directory and install dependencies once more without --prefer-source flag.
AFAIR there was also an issue when you did not have curl extension installed, then simply add this extension.