Doctrine\Common\DataFixtures\Sorter\TopologicalSorter::visit PHP Method

    private function visit(Vertex $definition)
    {
        $definition->state = Vertex::IN_PROGRESS;
        foreach ($definition->dependencyList as $dependency) {
            if (!isset($this->nodeList[$dependency])) {
                throw new \RuntimeException(sprintf('Fixture "%s" has a dependency of fixture "%s", but it not listed to be loaded.', get_class($definition->value), $dependency));
            }
            $childDefinition = $this->nodeList[$dependency];
            // allow self referencing classes
            if ($definition === $childDefinition) {
                continue;
            }
            switch ($childDefinition->state) {
                case Vertex::VISITED:
                    break;
                case Vertex::IN_PROGRESS:
                    if (!$this->allowCyclicDependencies) {
                        throw new CircularReferenceException(sprintf('Graph contains cyclic dependency between the classes "%s" and' . ' "%s". An example of this problem would be the following: ' . 'Class C has class B as its dependency. Then, class B has class A has its dependency. ' . 'Finally, class A has class C as its dependency.', $definition->value->getName(), $childDefinition->value->getName()));
                    }
                    break;
                case Vertex::NOT_VISITED:
                    $this->visit($childDefinition);
            }
        }
        $definition->state = Vertex::VISITED;
        $this->sortedNodeList[] = $definition->value;
    }