Empty dump() output in Symfony CLI

For some reason, it looks like what you are trying to do is actually dependency injecting a specific handler into VarDumper

So the condition null === self::$handler is always false in the below reproduced snippet of that class code, and, thus, the dumper you expect for 'cli' === PHP_SAPI is not set.

public static function dump($var){    if (null === self::$handler) {    /**       ^--- this one       **/        $cloner = new VarCloner();        $dumper = 'cli' === PHP_SAPI ? new CliDumper() : new HtmlDumper();        self::$handler = function ($var) use ($cloner, $dumper) {            $dumper->dump($cloner->cloneVar($var));        };    }    return call_user_func(self::$handler, $var);}

source: Symfony/Component/VarDumper/VarDumper.php

Now, knowing this, your solution is as easy as just setting the handler of VarDumper back to null

Working code:

# bin/app_dev_cli.php<?phpuse Symfony\Component\VarDumper\VarDumper;require __DIR__.'/../app/autoload.php';$kernel = new AppKernel('dev', true);$kernel->boot();/** This line (plus the use statement on top) does what you want **/VarDumper::setHandler(null);// Useful global vars$container = $kernel->getContainer();$doctrine = $container->get('doctrine');$em = $doctrine->getManager();

When run:

$ php -aInteractive shellphp > require 'bin/app_dev_cli.php';# bin/app_dev_cli.php php > dump('hi'); "hi"