Ошибка установки XHP с композитором

Я пытаюсь установить XHP на OSX, используя composer. У меня есть каталог с composer.phar и composer.json. Мой файл composer.json выглядит так:

{
"require": {
"facebook/xhp-lib": "~2.2"}
}

Я также установил последнюю версию HHVM. Я пробовал бегать

hhvm composer.phar install --verbose

но получил следующую ошибку:

[ErrorException]
Undefined index: 0Exception trace:
() at phar://composer.phar/bin/../src/../vendor/symfony/process/Pipes/AbstractPipes.php:140
Composer\Util\ErrorHandler::handle() at phar://composer.phar/bin/../src/../vendor/symfony/process/Pipes/AbstractPipes.php:140
Symfony\Component\Process\Pipes\AbstractPipes->write() at phar://composer.phar/bin/../src/../vendor/symfony/process/Pipes/UnixPipes.php:98
Symfony\Component\Process\Pipes\UnixPipes->readAndWrite() at phar://composer.phar/bin/../src/../vendor/symfony/process/Process.php:1359
Symfony\Component\Process\Process->readPipes() at phar://composer.phar/bin/../src/../vendor/symfony/process/Process.php:1279
Symfony\Component\Process\Process->updateStatus() at phar://composer.phar/bin/../src/../vendor/symfony/process/Process.php:305
Symfony\Component\Process\Process->start() at phar://composer.phar/bin/../src/../vendor/symfony/process/Process.php:201
Symfony\Component\Process\Process->run() at phar://composer.phar/bin/../src/../src/Composer/Util/ProcessExecutor.php:68
Composer\Util\ProcessExecutor->execute() at phar://composer.phar/bin/../src/../src/Composer/Package/Version/VersionGuesser.php:88
Composer\Package\Version\VersionGuesser->guessGitVersion() at phar://composer.phar/bin/../src/../src/Composer/Package/Version/VersionGuesser.php:67
Composer\Package\Version\VersionGuesser->guessVersion() at phar://composer.phar/bin/../src/../src/Composer/Package/Loader/RootPackageLoader.php:76
Composer\Package\Loader\RootPackageLoader->load() at phar://composer.phar/bin/../src/../src/Composer/Factory.php:332
Composer\Factory->createComposer() at phar://composer.phar/bin/../src/../src/Composer/Factory.php:552
Composer\Factory::create() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:308
Composer\Console\Application->getComposer() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:420
Composer\Console\Application->getPluginCommands() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:131
Composer\Console\Application->doRun() at phar://composer.phar/bin/../src/../vendor/symfony/console/Application.php:123
Symfony\Component\Console\Application->run() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:102
Composer\Console\Application->run() at phar://composer.phar/bin/composer:43
include() at /Users/chrisapa/Sites/project1/composer.phar:24

Я не уверен, что делать отсюда.