src/Composer/Repository/CompositeRepository.php
public function addRepository(RepositoryInterface $repository)
    {
        if ($repository instanceof self) {
            foreach ($repository->getRepositories() as $repo) {
                $this->addRepository($repo);
            }
        } else {
            $this->repositories[] = $repository;
        }
    }
public function addRepository(RepositoryInterface $repository)
    {
        if ($repository instanceof self) {
            foreach ($repository->getRepositories() as $repo) {
                $this->addRepository($repo);
            }
        } else {
            $this->repositories[] = $repository;
        }
    }
Add a repository.
@param RepositoryInterface $repository