Empty dump() output in Symfony CLI

Question

I'm building a simple Symfony-shell script to test my Symfony app on interactive mode:

# bin/app_dev_cli.php

require __DIR__.'/../app/autoload.php';

$kernel = new AppKernel('dev', true);
// Initialize bundles and container
$kernel->boot();

// Useful global vars
$container = $kernel->getContainer();
$doctrine = $container->get('doctrine');
$em = $doctrine->getManager();

Later, opening PHP interactive mode and including the previous script I can do some tasks quickly:

/path/to/symfony/project$ php -a
Interactive mode enabled

# Booting the Symfony-shell app
php > require 'bin/app_dev_cli.php';

# Check if one service has been registered successfully
php > dump( $container->has('some_service') );

# Test some service
php > dump( $container->get('some_service')->run($param) );

# Manage some entities and DB data flow
php > $apple = new AppBundle\Entity\Fruit('Apple');
php > $em->persist($apple);
php > $em->flush();

php > dump( $em->getRepository('AppBundle\Entity\Fluit')->findAll() );

# etc.

The problem here is that the dump() function shows nothing. I was expecting a colored command line output, however I tried this with echo or var_dump() and it works, but for objects mainly the output is dense and unreadable. In this direction the VarDumper Component documentation says:

By default, the output format and destination are selected based on your current PHP SAPI [...] * On the command line (CLI SAPI), the output is written on STDOUT. [...]

That's not working for me by default and I'm sure that PHP_SAPI is cli. Besides, I found a workaround setting debug.dump_destination to php://stderr, BUT:

# php interactive mode:
php > dump("test");
hp shell code on line 1: // <---- show the code line always
"test"

I don't like this output and neither change the config for this purpose only.

Any thoughts what happens with the dump() function and why it shows nothing? Thanks.

Answer 1

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
<?php
use 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 -a
Interactive shell

php > require 'bin/app_dev_cli.php';
# bin/app_dev_cli.php 
php > dump('hi'); 
"hi"