Some edge-cases with Symfony Validator might force you to create a constraint dynamically during the validation. This article will show you how to do it and how to solve error mapping for such constraints.
In some more complicated cases you need to do some validations only if some condition is met. This article covers the tricks you should use including a new feature in Symfony 3.2.
With Symfony/Validator there is no obvious way to implement validations like comparing a value to another property on the same object. There are several articles about this topic already but literally all of them are completely outdated. In this article I'll cover the correct way to solve this.