<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\DependencyInjection\Compiler;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;
/**
* Checks your services for circular references.
*
* References from method calls are ignored since we might be able to resolve
* these references depending on the order in which services are called.
*
* Circular reference from method calls will only be detected at run-time.
*
* @author Johannes M. Schmitt <schmittjoh@gmail.com>
*/
class CheckCircularReferencesPass implements CompilerPassInterface
{
private array $currentPath;
private array $checkedNodes;
private array $checkedLazyNodes;
/**
* Checks the ContainerBuilder object for circular references.
*/
public function process(ContainerBuilder $container): void
{
$graph = $container->getCompiler()->getServiceReferenceGraph();
$this->checkedNodes = [];
foreach ($graph->getNodes() as $id => $node) {
$this->currentPath = [$id];
$this->checkOutEdges($node->getOutEdges());
}
}
/**
* Checks for circular references.
*
* @param ServiceReferenceGraphEdge[] $edges An array of Edges
*
* @throws ServiceCircularReferenceException when a circular reference is found
*/
private function checkOutEdges(array $edges): void
{
foreach ($edges as $edge) {
$node = $edge->getDestNode();
$id = $node->getId();
if (!empty($this->checkedNodes[$id])) {
continue;
}
$isLeaf = (bool) $node->getValue();
$isConcrete = !$edge->isLazy() && !$edge->isWeak();
// Skip already checked lazy services if they are still lazy. Will not gain any new information.
if (!empty($this->checkedLazyNodes[$id]) && (!$isLeaf || !$isConcrete)) {
continue;
}
// Process concrete references, otherwise defer check circular references for lazy edges.
if (!$isLeaf || $isConcrete) {
$searchKey = array_search($id, $this->currentPath);
$this->currentPath[] = $id;
if (false !== $searchKey) {
throw new ServiceCircularReferenceException($id, \array_slice($this->currentPath, $searchKey));
}
$this->checkOutEdges($node->getOutEdges());
$this->checkedNodes[$id] = true;
unset($this->checkedLazyNodes[$id]);
} else {
$this->checkedLazyNodes[$id] = true;
}
array_pop($this->currentPath);
}
}
}