rector/bin/container.php

<?php

declare(strict_types=1);

use Rector\Console\Option\SetOptionResolver;
use Rector\DependencyInjection\RectorContainerFactory;
use Rector\Exception\Configuration\SetNotFoundException;
use Rector\Set\Set;
use Symfony\Component\Console\Input\ArgvInput;
use Symplify\PackageBuilder\Configuration\ConfigFileFinder;
use Symplify\PackageBuilder\Console\ShellCode;
use Symplify\PackageBuilder\Console\Style\SymfonyStyleFactory;

$configs = [];

// Detect configuration from --set
try {
    $input = new ArgvInput();
    $setOptionResolver = new SetOptionResolver();
    $configs[] = $setOptionResolver->detectFromInputAndDirectory($input, Set::SET_DIRECTORY);
} catch (SetNotFoundException $setNotFoundException) {
    $symfonyStyle = (new SymfonyStyleFactory())->create();
    $symfonyStyle->error($setNotFoundException->getMessage());
    exit(ShellCode::ERROR);
}

// And from --config or default one
ConfigFileFinder::detectFromInput('rector', new ArgvInput());
$configs[] = ConfigFileFinder::provide('rector', ['rector.yml', 'rector.yaml']);

// remove empty values
$configs = array_filter($configs);

// Build DI container
$rectorContainerFactory = new RectorContainerFactory();
return $rectorContainerFactory->createFromConfigs($configs);