Cover of the book Symfony 5: The Fast Track

Symfony 5: The Fast Track is the best book to learn modern Symfony development, from zero to production. +300 pages showcasing Symfony with Docker, APIs, queues & async tasks, Webpack, SPAs, etc.


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How to optimize your development Environment for debugging

2.2 version

How to optimize your development Environment for debugging

When you work on a Symfony project on your local machine, you should use the dev environment (app_dev.php front controller). This environment configuration is optimized for two main purposes:

  • Give the developer accurate feedback whenever something goes wrong (web debug toolbar, nice exception pages, profiler, …);
  • Be as similar as possible as the production environment to avoid problems when deploying the project.

Disabling the Bootstrap File and Class Caching

And to make the production environment as fast as possible, Symfony creates big PHP files in your cache containing the aggregation of PHP classes your project needs for every request. However, this behavior can confuse your IDE or your debugger. This recipe shows you how you can tweak this caching mechanism to make it friendlier when you need to debug code that involves Symfony classes.

The app_dev.php front controller reads as follows by default:

// ...

$loader = require_once __DIR__.'/../app/bootstrap.php.cache';
require_once __DIR__.'/../app/AppKernel.php';

$kernel = new AppKernel('dev', true);
$request = Request::createFromGlobals();

To make your debugger happier, disable all PHP class caches by removing the call to loadClassCache() and by replacing the require statements like below:

// ...

// $loader = require_once __DIR__.'/../app/bootstrap.php.cache';
$loader = require_once __DIR__.'/../app/autoload.php';
require_once __DIR__.'/../app/AppKernel.php';

use Symfony\Component\HttpFoundation\Request;

$kernel = new AppKernel('dev', true);
// $kernel->loadClassCache();
$request = Request::createFromGlobals();


If you disable the PHP caches, don’t forget to revert after your debugging session.

Some IDEs do not like the fact that some classes are stored in different locations. To avoid problems, you can either tell your IDE to ignore the PHP cache files, or you can change the extension used by Symfony for these files:

$kernel->loadClassCache('classes', '.php.cache');

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.