How do you check if an object exists in the Twig templating engine in Symfony2?

Quickly did a lookup, hope this is works for you :p

defined

defined checks if a variable is defined in the current context. This is very useful if you use the strict_variables option:

{# defined works with variable names #}
{% if foo is defined %}
    ...
{% endif %}

{# and attributes on variables names #}
{% if foo.bar is defined %}
    ...
{% endif %}