I use Symfony 2 with Twig and my question is pretty straightforward:
In a view I want to extend one of the layouts based on a variable. If the variable is fals
You cannot extends multiple template, that's why you've got the error, if you want to so, you need to push them in an array like below.
{% extends ['MyAppCustomBundle::Layout/layout.html.twig', 'FOSUserBundle::layout.html.twig'] %}
But you will need to use Twig version 1.2 to do it. twig documentation