Why register annotations is required during the installation process

[murilolobato]

Reading the installation instructions on symfony.com and in the own repo docs (which is referenced by the symfony webpage) it says to add the following code to app/autoload.php:

use Doctrine\ODM\MongoDB\Mapping\Driver\AnnotationDriver;
AnnotationDriver::registerAnnotationClasses();

I've just discovered that my application is running without this code about two years. Is this call still necessary? What this does?

[malarzm]

This is pre-composer way of including ODM annotations, you can do perfectly fine without it, especially using Symfony. The AnnotationDriver::registerAnnotationClasses(); call was deprecated and will be removed in ODM 2.0.

[malarzm]

Ah, feel free to re-open if you have any suggestions :)