symfony/symfony-docs — pull request #4202 by xabbuh (2014-09-05 10:22:58+00:00)
Title: [Reference][Constraints] caution on `null` values in Expression constraint

| Q | A
| ------------- | ---
| Doc fix? | yes
| New docs? | no
| Applies to | 2.4, 2.5
| Fixed tickets | part of #4191

This adds a warning to the reference of the Expression constraint explaining that `null` values won't be validated in Symfony 2.4 and Symfony 2.5.