MAGETWO-37710: Setup wizard fails in readiness check when magento is deployed by composer create-project

- fixed missed COMPOSER_HOME directory

Author: Ivan Gavryshko

lib/internal/Magento/Framework/App/Filesystem/DirectoryList.php

@@ -110,6 +110,11 @@ class DirectoryList extends \Magento\Framework\Filesystem\DirectoryList
      */
     const UPLOAD = 'upload';
 
+    /**
+     * Directory to store composer related files (config, cache etc.) in case if composer runs by Magento Application
+     */
+    const COMPOSER_HOME = 'composer_home';
+
     /**
      * A suffix for temporary materialization directory where pre-processed files will be written (if necessary)
      */
@@ -145,6 +150,7 @@ public static function getDefaultConfig()
             self::TMP_MATERIALIZATION_DIR => [parent::PATH => 'var/view_preprocessed'],
             self::TEMPLATE_MINIFICATION_DIR => [parent::PATH => 'var/view_preprocessed/html'],
             self::SETUP => [parent::PATH => 'setup/src'],
+            self::COMPOSER_HOME => [parent::PATH => 'var/composer_home'],
         ];
         return parent::getDefaultConfig() + $result;
     }

setup/src/Magento/Setup/Model/ComposerInformation.php

@@ -50,6 +50,8 @@ public function __construct(
             throw new \Exception('Composer file not found: ' . $composerJson);
         }
 
+        putenv('COMPOSER_HOME='.$filesystem->getDirectoryRead(DirectoryList::COMPOSER_HOME)->getAbsolutePath());
+
         // Create Composer
         $this->composer = ComposerFactory::create($io, $composerJson);
         $this->locker = $this->composer->getLocker();