ErrorException Undefined index: 0 - hhvm and composer - php

Question

I'm trying to run:
hhvm $(brew --prefix)/bin/composer.phar
With:
HipHop VM 3.14.3 (rel)
Compiler: 1471660550_N
Repo schema: 90201df99a45497953c42400d58fb97663717b4a
But I get:
Any ideas? Can't really move forward from here. I think it might be similar to: Error installing XHP with composer
Running:
hhvm composer.phar --verbose
I get:
Exception 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:94
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:333
Composer\Factory->createComposer() at phar://composer.phar/bin/../src/../src/Composer/Factory.php:554
Composer\Factory::create() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:318
Composer\Console\Application->getComposer() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:430
Composer\Console\Application->getPluginCommands() at phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:135
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:104
Composer\Console\Application->run() at phar://composer.phar/bin/composer:43
include() at /Users/alexpchin/work_wordpress/pad-wordpress/composer.phar:24
Update
If I add a version "version": "1.2.0", to the composer.json file - I get:
Loading composer repositories with package information
Updating dependencies (including require-dev)
Core dumped: Segmentation fault: 11
Stack trace in /tmp/stacktrace.2219.log
[1] 2219 segmentation fault hhvm $(brew --prefix)/bin/composer.phar update
This is the stacktrace:
PHP Stacktrace:
#0 json_decode() called at [phar://composer.phar/bin/../src/../src/Composer/Repository/ComposerRepository.php:556]
#1 Composer\Repository\ComposerRepository->loadProviderListings() called at [phar://composer.phar/bin/../src/../src/Composer/Repository/ComposerRepository.php:289]
#2 Composer\Repository\ComposerRepository->whatProvides() called at [phar://composer.phar/bin/../src/../src/Composer/DependencyResolver/Pool.php:204]
#3 Composer\DependencyResolver\Pool->computeWhatProvides() called at [phar://composer.phar/bin/../src/../src/Composer/DependencyResolver/Pool.php:193]
#4 Composer\DependencyResolver\Pool->whatProvides() called at [phar://composer.phar/bin/../src/../src/Composer/DependencyResolver/RuleSetGenerator.php:168]
#5 Composer\DependencyResolver\RuleSetGenerator->whitelistFromPackage() called at [phar://composer.phar/bin/../src/../src/Composer/DependencyResolver/RuleSetGenerator.php:322]
#6 Composer\DependencyResolver\RuleSetGenerator->getRulesFor() called at [phar://composer.phar/bin/../src/../src/Composer/DependencyResolver/Solver.php:214]
#7 Composer\DependencyResolver\Solver->solve() called at [phar://composer.phar/bin/../src/../src/Composer/Installer.php:461]
#8 Composer\Installer->doInstall() called at [phar://composer.phar/bin/../src/../src/Composer/Installer.php:216]
#9 Composer\Installer->run() called at [phar://composer.phar/bin/../src/../src/Composer/Command/InstallCommand.php:135]
#10 Composer\Command\InstallCommand->execute() called at [phar://composer.phar/bin/../src/../vendor/symfony/console/Command/Command.php:259]
#11 Symfony\Component\Console\Command\Command->run() called at [phar://composer.phar/bin/../src/../vendor/symfony/console/Application.php:844]
#12 Symfony\Component\Console\Application->doRunCommand() called at [phar://composer.phar/bin/../src/../vendor/symfony/console/Application.php:192]
#13 Symfony\Component\Console\Application->doRun() called at [phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:231]
#14 Composer\Console\Application->doRun() called at [phar://composer.phar/bin/../src/../vendor/symfony/console/Application.php:123]
#15 Symfony\Component\Console\Application->run() called at [phar://composer.phar/bin/../src/../src/Composer/Console/Application.php:104]
#16 Composer\Console\Application->run() called at [phar://composer.phar/bin/composer:43]
#17 include() called at [/usr/local/bin/composer.phar:24]