Debug helpers for Symfony2/Twig

config_dev.yml

services:
    twig.extension.debug:
        class: Twig_Extension_Debug
        tags:
            - { name: twig.extension }

    twig.extension.infinite_debug:
        class: Infinite\Helper\Twig\Debug
        tags:
            - { name: twig.extension }

Debug.php

<?php

namespace Infinite\Helper\Twig;

use Doctrine\Common\Util\Debug as DoctrineDebug;

class Debug extends \Twig_Extension
{
    /**
     * Returns a list of global functions to add to the existing list.
     *
     * @return array An array of global functions
     */
    public function getFunctions()
    {
        // dump is safe if var_dump is overriden by xdebug
        $isDumpOutputHtmlSafe = extension_loaded('xdebug') &&
            (
                false === get_cfg_var('xdebug.overload_var_dump') ||
                get_cfg_var('xdebug.overload_var_dump')
            ) &&
            get_cfg_var('html_errors');

        return array(
            'doctrine_dump' => new \Twig_Function_Method($this, 'dump', array(
                'is_safe' => $isDumpOutputHtmlSafe ? array('html') : array(),
                'needs_context' => true,
                'needs_environment' => true
            )),
            'dd' => new \Twig_Function_Method($this, 'dump', array(
                'is_safe' => $isDumpOutputHtmlSafe ? array('html') : array(),
                'needs_context' => true,
                'needs_environment' => true
            ))
        );
    }

    public function dump(\Twig_Environment $env, $context)
    {
        // Taken from twig_var_dump();
        if (!$env->isDebug()) {
            return '';
        }

        ob_start();

        $count = func_num_args();
        if (2 === $count) {
            $vars = array();
            foreach ($context as $key => $value) {
                if (!$value instanceof \Twig_Template) {
                    $vars[$key] = $value;
                }
            }

            DoctrineDebug::dump($vars, 3);
        } else {
            $depth = ($count > 3 and is_integer(func_get_arg($count - 1))) ? func_get_arg($count - 1) : 3;
            for ($i = 2; $i < $count; $i++) {
                DoctrineDebug::dump(func_get_arg($i), $depth);
            }
        }

        return ob_get_clean();
    }

    /**
     * Returns the name of the extension.
     *
     * @return string The extension name
     */
    public function getName()
    {
        return 'infinite_debug';
    }
}

when using Twig 1.5 (which comes by default with Symfony2 now), you should use the new Twig_Extension_Debug class instead