Exception trace:
  at phar:///usr/local/bin/composer/src/Composer/Util/ProcessExecutor.php:149
 Composer\Util\ProcessExecutor->executeAsync() at phar:///usr/local/bin/composer/src/Composer/Package/Version/VersionGuesser.php:324
 Composer\Package\Version\VersionGuesser->guessFeatureVersion() at phar:///usr/local/bin/composer/src/Composer/Package/Version/VersionGuesser.php:181
 Composer\Package\Version\VersionGuesser->guessGitVersion() at phar:///usr/local/bin/composer/src/Composer/Package/Version/VersionGuesser.php:77
 Composer\Package\Version\VersionGuesser->guessVersion() at phar:///usr/local/bin/composer/src/Composer/Repository/PathRepository.php:215
 Composer\Repository\PathRepository->initialize() at phar:///usr/local/bin/composer/src/Composer/Repository/ArrayRepository.php:311
 Composer\Repository\ArrayRepository->getPackages() at phar:///usr/local/bin/composer/src/Composer/Repository/ArrayRepository.php:62
 Composer\Repository\ArrayRepository->loadPackages() at phar:///usr/local/bin/composer/src/Composer/DependencyResolver/PoolBuilder.php:381
 Composer\DependencyResolver\PoolBuilder->loadPackagesMarkedForLoading() at phar:///usr/local/bin/composer/src/Composer/DependencyResolver/PoolBuilder.php:234
 Composer\DependencyResolver\PoolBuilder->buildPool() at phar:///usr/local/bin/composer/src/Composer/Repository/RepositorySet.php:260
 Composer\Repository\RepositorySet->createPool() at phar:///usr/local/bin/composer/src/Composer/Installer.php:436
 Composer\Installer->doUpdate() at phar:///usr/local/bin/composer/src/Composer/Installer.php:279
 Composer\Installer->run() at phar:///usr/local/bin/composer/src/Composer/Command/UpdateCommand.php:241
 Composer\Command\UpdateCommand->execute() at phar:///usr/local/bin/composer/vendor/symfony/console/Command/Command.php:298
 Symfony\Component\Console\Command\Command->run() at phar:///usr/local/bin/composer/vendor/symfony/console/Application.php:1015
 Symfony\Component\Console\Application->doRunCommand() at phar:///usr/local/bin/composer/vendor/symfony/console/Application.php:299
 Symfony\Component\Console\Application->doRun() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:334
 Composer\Console\Application->doRun() at phar:///usr/local/bin/composer/vendor/symfony/console/Application.php:171
 Symfony\Component\Console\Application->run() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:130
 Composer\Console\Application->run() at phar:///usr/local/bin/composer/bin/composer:88
 require() at /usr/local/bin/composer:29