src/Composer/Installer/InstallationManager.php
public function markAliasInstalled(RepositoryInterface $repo, MarkAliasInstalledOperation $operation)
    {
        $package = $operation->getPackage();

        if (!$repo->hasPackage($package)) {
            $repo->addPackage(clone $package);
        }
    }
public function markAliasInstalled(RepositoryInterface $repo, MarkAliasInstalledOperation $operation)
    {
        $package = $operation->getPackage();

        if (!$repo->hasPackage($package)) {
            $repo->addPackage(clone $package);
        }
    }
Executes markAliasInstalled operation.

@param RepositoryInterface         $repo      repository in which to check
@param MarkAliasInstalledOperation $operation operation instance