woocommerce-paypal-payments/bootstrap.php

<?php
/**
 * Bootstraps the modular app.
 *
 * @package WooCommerce\PayPalCommerce
 */

use WooCommerce\PayPalCommerce\Vendor\Dhii\Container\CachingContainer;
use WooCommerce\PayPalCommerce\Vendor\Dhii\Container\CompositeCachingServiceProvider;
use WooCommerce\PayPalCommerce\Vendor\Dhii\Container\CompositeContainer;
use WooCommerce\PayPalCommerce\Vendor\Dhii\Container\DelegatingContainer;
use WooCommerce\PayPalCommerce\Vendor\Dhii\Container\ProxyContainer;
use WooCommerce\PayPalCommerce\Vendor\Dhii\Modular\Module\ModuleInterface;
use WooCommerce\PayPalCommerce\Vendor\Interop\Container\ServiceProviderInterface;
use WooCommerce\PayPalCommerce\Vendor\Psr\Container\ContainerInterface;

return function (
	string $root_dir,
	array $additional_containers = array(),
	array $additional_modules = array()
): ContainerInterface {
	/**
	 * Skip path check.
	 *
	 * @psalm-suppress UnresolvableInclude
	 */
	$modules = ( require "$root_dir/modules.php" )( $root_dir );

	$modules = array_merge( $modules, $additional_modules );

	/**
	 * Use this filter to add custom module or remove some of existing ones.
	 * Modules able to access container, add services and modify existing ones.
	 */
	$modules = apply_filters( 'woocommerce_paypal_payments_modules', $modules );

	$providers = array_map(
		function ( ModuleInterface $module ): ServiceProviderInterface {
			return $module->setup();
		},
		$modules
	);

	$provider        = new CompositeCachingServiceProvider( $providers );
	$proxy_container = new ProxyContainer();
	// TODO: caching does not work currently,
	// may want to consider fixing it later (pass proxy as parent to DelegatingContainer)
	// for now not fixed since we were using this behavior for long time and fixing it now may break things.
	$container = new DelegatingContainer( $provider );
	/**
	 * Skip iterable vs array check.
	 *
	 * @psalm-suppress PossiblyInvalidArgument
	 */
	$app_container = new CachingContainer(
		new CompositeContainer(
			array_merge(
				$additional_containers,
				array( $container )
			)
		)
	);
	$proxy_container->setInnerContainer( $app_container );

	foreach ( $modules as $module ) {
		/* @var $module ModuleInterface module */
		$module->run( $app_container );
	}

	return $app_container;
};