title: Upgrading from symfony 2.1.7 to symfony 2.1.8
body: <p>I ran composer update command and it updated from symfony 2.1.7 to symfony 2.1.8. This is where my problem started. Now when I try to run any symfony console command, I get error as below:</p>
  
  <pre><code> Fatal error: Class 'Symfony\Component\Console\Input\ArgvInput' not found in C:\xampp\htdocs\myproject\app\console on line 16
  </code></pre>
  
  <p>When I run my project in browser I get this error:</p>
  
  <pre><code>Fatal error: Class 'Symfony\Component\ClassLoader\DebugClassLoader' not found in C:\xampp\htdocs\myproject\app\bootstrap.php.cache on line 542
  </code></pre>
  
  <p>Previously it was working all fine.</p>
  
  <p>How do I fix this ?</p>
  
  <p>Here is my composer.json:</p>
  
  <pre><code>{
  "name": "symfony/framework-standard-edition",
  "description": "The \"Symfony Standard Edition\" distribution",
  "autoload": {
      "psr-0": { "": "src/" }
  },
  "require": {
      "php": "&gt;=5.3.3",
      "symfony/symfony": "2.1.7",
      "imagine/Imagine": "&gt;=0.2.8",
      "liip/imagine-bundle": "*@dev",
      "knplabs/knp-paginator-bundle": "dev-master",
      "cbsi/doctrine2-nestedset": "dev-master",
      "exercise/htmlpurifier-bundle": "dev-master",
      "doctrine/orm": "&gt;=2.2.3,&lt;2.4-dev",
      "doctrine/doctrine-bundle": "1.0.*",
      "twig/extensions": "1.0.*@dev",
      "symfony/assetic-bundle": "2.1.*",
      "symfony/swiftmailer-bundle": "2.1.*",
      "symfony/monolog-bundle": "2.1.*",
      "sensio/distribution-bundle": "2.1.*",
      "sensio/framework-extra-bundle": "2.1.*",
      "sensio/generator-bundle": "2.1.*",
      "jms/security-extra-bundle": "1.2.*",
      "jms/di-extra-bundle": "1.1.*",
      "kriswallsmith/assetic": "1.1.*@dev"
  },
  "scripts": {
      "post-install-cmd": [
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
      ],
      "post-update-cmd": [
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
          "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
      ]
  },
  "extra": {
      "symfony-app-dir": "app",
      "symfony-web-dir": "web"
  }
  }
  </code></pre>