Why does twig template throw unknown "dump" function when using if statement for 'dev' environment?

Question

I have a twig template using Symfony3 like the follwing:

{% if app.environment == 'dev' %}
    {{ dump(students) }}
{% endif %}

But in the 'prod' environment it throws this error, shown in the var/logs/prod.log file:

[2016-05-18 21:28:28] request.CRITICAL: Uncaught PHP Exception Twig_Error_Syntax: "Unknown "dump" function in "search/search_pet_results.html.twig" at line 13." at /var/www/html/petition/vendor/twig/twig/lib/Twig/ExpressionParser.php line 573 {"exception":"[object] (Twig_Error_Syntax(code: 0): Unknown \"dump\" function in \"search/search_pet_results.html.twig\" at line 13. at /var/www/html/petition/vendor/twig/twig/lib/Twig/ExpressionParser.php:573)"} []

Any suggestions for my twig template? Don't know what to try, because this is "supposed" to work.

Answer 1

The dump function is not available by default, as described in the doc here . You must set the debug flag to true in order to enable on the environment. The flag is located in the config.yml files, under the twig section. Usually the value is taken from the kernel value.

So probably your config.yml is same as follow:

config.yml

# Twig Configuration
twig:
    debug:            "%kernel.debug%"

Try modify as follow in order to enable in all the environment:

config.yml

# Twig Configuration
twig:
    debug:            true

Hope this help