Error while trying to upgrade magento through composer

Question

I am trying to update magento/product-community-edition 2.0.5 to version 2.1.0. To do that I replaced version in composer.json and tried to run composer update -vvv. Unfortunately, script is failing due to an error:

[UnexpectedValueException]                                                                                 
  Package magento/composer's source key should be specified as {"type": ..., "url": ..., "reference": ...},  
  {"type":"git","url":"https:\/\/github.com\/magento\/composer.git","reference":null} given. 

I am attaching full exception trace below. Any ideas?

Steps I made:

1. I tried to run it from vagrant, as well as from my mac console.
2. I updated composer to newest alpha.

Any help will be highly appreciated as I am pulling my hairs from my head for over an hour.

Reading ./composer.json
Loading config file ./composer.json
Checked CA file /etc/ssl/certs/ca-certificates.crt: valid
Reading /home/vagrant/.config/composer/composer.json
Loading config file /home/vagrant/.config/composer/composer.json
Reading /home/vagrant/Code/tandh/magento/public_html/vendor/composer/installed.json


  [UnexpectedValueException]                                                                                 
  Package magento/composer's source key should be specified as {"type": ..., "url": ..., "reference": ...},  
  {"type":"git","url":"https:\/\/github.com\/magento\/composer.git","reference":null} given.                 


Exception trace:
 () at phar:///usr/local/bin/composer/src/Composer/Package/Loader/ArrayLoader.php:83
 Composer\Package\Loader\ArrayLoader->load() at phar:///usr/local/bin/composer/src/Composer/Repository/FilesystemRepository.php:63
 Composer\Repository\FilesystemRepository->initialize() at phar:///usr/local/bin/composer/src/Composer/Repository/ArrayRepository.php:181
 Composer\Repository\ArrayRepository->getPackages() at phar:///usr/local/bin/composer/src/Composer/Plugin/PluginManager.php:250
 Composer\Plugin\PluginManager->loadRepository() at phar:///usr/local/bin/composer/src/Composer/Plugin/PluginManager.php:76
 Composer\Plugin\PluginManager->loadInstalledPlugins() at phar:///usr/local/bin/composer/src/Composer/Factory.php:361
 Composer\Factory->createComposer() at phar:///usr/local/bin/composer/src/Composer/Factory.php:552
 Composer\Factory::create() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:308
 Composer\Console\Application->getComposer() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:420
 Composer\Console\Application->getPluginCommands() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:131
 Composer\Console\Application->doRun() at phar:///usr/local/bin/composer/vendor/symfony/console/Application.php:123
 Symfony\Component\Console\Application->run() at phar:///usr/local/bin/composer/src/Composer/Console/Application.php:102
 Composer\Console\Application->run() at phar:///usr/local/bin/composer/bin/composer:43
 require() at /usr/local/bin/composer:24

Answer 1

If you are going from 2.0.5 to 2.1.0 have you applied patch "MDVA-532" which is described as "Patch MDVA-532 fixes an issue with the Magento composer-installer component that causes upgrades to fail."

More details here: http://devdocs.magento.com/guides/v2.0/release-notes/tech_bull_21-upgrade.html

If no joy with that - maybe post your composer.json here.