Throwing errors if composer json does not contain all options

[skors]

Hi,

if the composer json in the required is not complete, an error is thrown:

PHP Notice:  Undefined property: stdClass::$zip in phar:///opt/tools/phpmetrics/extensions/composer-extension.phar/ComposerExtension.php on line 52
PHP Stack trace:
PHP   1. {main}() /usr/local/bin/phpmetrics:0
PHP   2. Symfony\Component\Console\Application->run() /usr/local/bin/phpmetrics:17
PHP   3. Symfony\Component\Console\Application->doRun() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:117
PHP   4. Symfony\Component\Console\Application->doRunCommand() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:186
PHP   5. Symfony\Component\Console\Command\Command->run() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:815
PHP   6. Hal\Application\Command\RunMetricsCommand->execute() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Command/Command.php:256
PHP   7. Hal\Application\Extension\ExtensionService->receive() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Command/RunMetricsCommand.php:156
PHP   8. ComposerExtension\ComposerExtension->receive() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Extension/ExtensionService.php:51

and another example

PHP Warning:  implode(): Invalid arguments passed in phar:///opt/tools/phpmetrics/extensions/composer-extension.phar/HtmlRenderer.php on line 81
PHP Stack trace:
PHP   1. {main}() /usr/local/bin/phpmetrics:0
PHP   2. Symfony\Component\Console\Application->run() /usr/local/bin/phpmetrics:17
PHP   3. Symfony\Component\Console\Application->doRun() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:117
PHP   4. Symfony\Component\Console\Application->doRunCommand() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:186
PHP   5. Symfony\Component\Console\Command\Command->run() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Application.php:815
PHP   6. Hal\Application\Command\RunMetricsCommand->execute() phar:///usr/local/bin/phpmetrics/vendor/symfony/console/Command/Command.php:256
PHP   7. Hal\Application\Command\Job\Queue->execute() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Command/RunMetricsCommand.php:163
PHP   8. Hal\Application\Command\Job\ReportWriter->execute() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Command/Job/Queue.php:51
PHP   9. Hal\Application\Formater\Summary\Html->terminate() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Command/Job/ReportWriter.php:75
PHP  10. Twig_Environment->render() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Formater/Summary/Html.php:91
PHP  11. Twig_Template->render() phar:///usr/local/bin/phpmetrics/vendor/twig/twig/lib/Twig/Environment.php:347
PHP  12. Twig_Template->display() phar:///usr/local/bin/phpmetrics/vendor/twig/twig/lib/Twig/Template.php:366
PHP  13. Twig_Template->displayWithErrorHandling() phar:///usr/local/bin/phpmetrics/vendor/twig/twig/lib/Twig/Template.php:355
PHP  14. __TwigTemplate_b26c8aec323d934747ab94470b20e7a36f5ff4f8a249a9ef862a1ddf72d09b30->doDisplay() phar:///usr/local/bin/phpmetrics/vendor/twig/twig/lib/Twig/Template.php:387
PHP  15. Hal\Application\Formater\Twig\FormatingExtension->extensionsContent() phar:///usr/local/bin/phpmetrics/vendor/twig/twig/lib/Twig/Environment.php(403) : eval()'d code:539
PHP  16. ComposerExtension\HtmlRenderer->renderHtml() phar:///usr/local/bin/phpmetrics/src/Hal/Application/Formater/Twig/FormatingExtension.php:118
PHP  17. implode() phar:///opt/tools/phpmetrics/extensions/composer-extension.phar/HtmlRenderer.php:81

I think it would be better to just output an information of the missing information rather then throwing a warning or notice.