mattsnowboard/composer.json

## composer.json
{
    "require": {
        "php": ">=5.4.11",
        "silex/silex": "~1.0",
        "silex/web-profiler": "~1.0",
        "symfony/browser-kit": "~2.3",
        "symfony/class-loader": "~2.3",
        "symfony/console": "~2.3",
        "symfony/config": "~2.3",
        "symfony/css-selector": "~2.3",
        "symfony/dom-crawler": "~2.3",
        "symfony/filesystem": "~2.3",
        "symfony/finder": "~2.3",
        "symfony/form": "~2.3",
        "symfony/locale": "~2.3",
        "symfony/process": "~2.3",
        "symfony/serializer": "~2.3",
        "symfony/translation": "~2.3",
        "symfony/validator": "~2.3",
        "symfony/twig-bridge": "~2.3",
        "twig/twig": ">=1.8,<2.0-dev",
    },
    "autoload": {
        "psr-0": { "": "src/" }
    }
}

## index_test.php
<?php

use Symfony\Component\ClassLoader\DebugClassLoader;
use Symfony\Component\HttpKernel\Debug\ErrorHandler;
use Symfony\Component\HttpKernel\Debug\ExceptionHandler;

require_once __DIR__.'/../vendor/autoload.php';

error_reporting(-1);
DebugClassLoader::enable();
ErrorHandler::register();
if ('cli' !== php_sapi_name()) {
    ExceptionHandler::register();
}

$env = 'dev';
$app = require __DIR__.'/../src/testapp.php';
$app->run();

## test.html.twig
<html>
    <head>
        <title>Test</title>
    </head>
    <body>
{{ form_start(form) }}

    {{ form_row(form.description) }}

    <h3>Tags</h3>
    <ul class="tasks" data-prototype="{{ form_widget(form.tasks.vars.prototype)|e }}">
        {# iterate over each existing tag and render its only field: name #}
        {% for task in form.tasks %}
            <li>{{ form_row(task.name) }}</li>
        {% endfor %}
    </ul>

    {{ form_widget(form.submit) }}
{{ form_end(form) }}

    <script>window.jQuery || document.write('<script src="/js/vendor/jquery-1.10.1.min.js"><\/script>')</script>
    <script>
        // Get the ul that holds the collection of tags
        var collectionHolder = $('ul.tasks');

        // setup an "add a tag" link
        var $addTaskLink = $('<a href="#" class="add_task_link">Add a task</a>');
        var $newLinkLi = $('<li></li>').append($addTaskLink);

        function addTaskForm(collectionHolder, $newLinkLi) {
            // Get the data-prototype explained earlier
            var prototype = collectionHolder.data('prototype');

            // get the new index
            var index = collectionHolder.data('index');

            // Replace '__name__' in the prototype's HTML to
            // instead be a number based on how many items we have
            var newForm = prototype.replace(/__name__/g, index);

            // increase the index with one for the next item
            collectionHolder.data('index', index + 1);

            // Display the form in the page in an li, before the "Add a tag" link li
            var $newFormLi = $('<li></li>').append(newForm);
            $newLinkLi.before($newFormLi);
        }

        jQuery(document).ready(function() {
            // add the "add a tag" anchor and li to the tags ul
            collectionHolder.append($newLinkLi);

            // count the current form inputs we have (e.g. 2), use that as the new
            // index when inserting a new item (e.g. 2)
            collectionHolder.data('index', collectionHolder.find(':input').length);

            $addTaskLink.on('click', function(e) {
                // prevent the link from creating a "#" on the URL
                e.preventDefault();

                // add a new tag form (see next code block)
                addTaskForm(collectionHolder, $newLinkLi);
            });
        });
    </script>

    </body>
</html>

## testapp.php
<?php

use Silex\Application;
use Silex\Provider\FormServiceProvider;
use Silex\Provider\ServiceControllerServiceProvider;
use Silex\Provider\SessionServiceProvider;
use Silex\Provider\SwiftmailerServiceProvider;
use Silex\Provider\TranslationServiceProvider;
use Silex\Provider\TwigServiceProvider;
use Silex\Provider\UrlGeneratorServiceProvider;
use Silex\Provider\ValidatorServiceProvider;

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

$app = new Application();

$app['debug'] = true;

$app->register(new FormServiceProvider());
$app->register(new ServiceControllerServiceProvider());
$app->register(new SessionServiceProvider());
$app->register(new SwiftmailerServiceProvider());
$app->register(new TranslationServiceProvider(), array(
    'locale_fallback' => 'en',
));

$app->register(new UrlGeneratorServiceProvider());
$app->register(new ValidatorServiceProvider());

// TWIG
$app->register(new TwigServiceProvider(), array(
    'twig.path'    => array(__DIR__.'/views'),
));

//
// MODEL
//

class Task
{
    protected $name;

    public function getName()
    {
        return $this->name;
    }

    public function setName($name)
    {
        $this->name = $name;
        return $this;
    }
}

class Project
{
    protected $description;

    protected $tasks;

    public function __construct()
    {
        $this->tasks = array();
    }

    public function getDescription()
    {
        return $this->description;
    }

    public function setDescription($description)
    {
        $this->description = $description;
        return $this;
    }

    public function getTasks()
    {
        return $this->tasks;
    }
    public function addTask(Task $task)
    {
        if (!is_null($task) && !in_array($task, $this->tasks)) {
            $this->tasks[] = $task;
        }
        return $this;
    }
    public function removeTask(Task $task)
    {
        if (!is_null($task)) {
            $this->tasks = array_diff($this->tasks, array($task));
        }
        return $this;
    }
}

//
// FORM
//

class TaskType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('name', 'text', array(
            'required' => false
        ));
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => '\Task',
        ));
    }

    public function getName()
    {
        return 'task';
    }
}

class ProjectType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('description', 'text', array())
            ->add('tasks', 'collection', array(
                'type' => new TaskType(),
                'allow_add'    => true,
                'by_reference' => false,
                'allow_delete' => true, // This causes the issue
                'required' => false
            ))
            ->add('submit', 'submit')
        ;
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => '\Project',
        ));
    }

    public function getName()
    {
        return 'project';
    }
}

//
// Controller
//

$app->match('/', function (Request $request) use ($app) {
    $project = new Project();

    // dummy code - this is here just so that the Task has some tags
    // otherwise, this isn't an interesting example
    $task1 = new Task();
    $task1->setName('A Task');
    $project->addTask($task1);
    // end dummy code

    $form = $app['form.factory']->create(new ProjectType(), $project);

    $form->handleRequest($request);

    if ($form->isValid()) {
        $data = $form->getData();
        $debug = print_r($data, true);
        echo $debug;
    }

    return $app['twig']->render('test.html.twig', array(
        'form' => $form->createView(),
    ));
})
->method('GET|POST')
;

return $app;
	{
	"require": {
	"php": ">=5.4.11",
	"silex/silex": "~1.0",
	"silex/web-profiler": "~1.0",
	"symfony/browser-kit": "~2.3",
	"symfony/class-loader": "~2.3",
	"symfony/console": "~2.3",
	"symfony/config": "~2.3",
	"symfony/css-selector": "~2.3",
	"symfony/dom-crawler": "~2.3",
	"symfony/filesystem": "~2.3",
	"symfony/finder": "~2.3",
	"symfony/form": "~2.3",
	"symfony/locale": "~2.3",
	"symfony/process": "~2.3",
	"symfony/serializer": "~2.3",
	"symfony/translation": "~2.3",
	"symfony/validator": "~2.3",
	"symfony/twig-bridge": "~2.3",
	"twig/twig": ">=1.8,<2.0-dev",
	},
	"autoload": {
	"psr-0": { "": "src/" }
	}
	}
	<?php

	use Symfony\Component\ClassLoader\DebugClassLoader;
	use Symfony\Component\HttpKernel\Debug\ErrorHandler;
	use Symfony\Component\HttpKernel\Debug\ExceptionHandler;

	require_once __DIR__.'/../vendor/autoload.php';

	error_reporting(-1);
	DebugClassLoader::enable();
	ErrorHandler::register();
	if ('cli' !== php_sapi_name()) {
	ExceptionHandler::register();
	}

	$env = 'dev';
	$app = require __DIR__.'/../src/testapp.php';
	$app->run();
	<html>
	<head>
	<title>Test</title>
	</head>
	<body>
	{{ form_start(form) }}

	{{ form_row(form.description) }}

	<h3>Tags</h3>
	<ul class="tasks" data-prototype="{{ form_widget(form.tasks.vars.prototype)\|e }}">
	{# iterate over each existing tag and render its only field: name #}
	{% for task in form.tasks %}
	<li>{{ form_row(task.name) }}</li>
	{% endfor %}
	</ul>

	{{ form_widget(form.submit) }}
	{{ form_end(form) }}

	<script>window.jQuery \|\| document.write('<script src="/js/vendor/jquery-1.10.1.min.js"><\/script>')</script>
	<script>
	// Get the ul that holds the collection of tags
	var collectionHolder = $('ul.tasks');

	// setup an "add a tag" link
	var $addTaskLink = $('<a href="#" class="add_task_link">Add a task</a>');
	var $newLinkLi = $('<li></li>').append($addTaskLink);

	function addTaskForm(collectionHolder, $newLinkLi) {
	// Get the data-prototype explained earlier
	var prototype = collectionHolder.data('prototype');

	// get the new index
	var index = collectionHolder.data('index');

	// Replace '__name__' in the prototype's HTML to
	// instead be a number based on how many items we have
	var newForm = prototype.replace(/__name__/g, index);

	// increase the index with one for the next item
	collectionHolder.data('index', index + 1);

	// Display the form in the page in an li, before the "Add a tag" link li
	var $newFormLi = $('<li></li>').append(newForm);
	$newLinkLi.before($newFormLi);
	}

	jQuery(document).ready(function() {
	// add the "add a tag" anchor and li to the tags ul
	collectionHolder.append($newLinkLi);

	// count the current form inputs we have (e.g. 2), use that as the new
	// index when inserting a new item (e.g. 2)
	collectionHolder.data('index', collectionHolder.find(':input').length);

	$addTaskLink.on('click', function(e) {
	// prevent the link from creating a "#" on the URL
	e.preventDefault();

	// add a new tag form (see next code block)
	addTaskForm(collectionHolder, $newLinkLi);
	});
	});
	</script>

	</body>
	</html>
	<?php

	use Silex\Application;
	use Silex\Provider\FormServiceProvider;
	use Silex\Provider\ServiceControllerServiceProvider;
	use Silex\Provider\SessionServiceProvider;
	use Silex\Provider\SwiftmailerServiceProvider;
	use Silex\Provider\TranslationServiceProvider;
	use Silex\Provider\TwigServiceProvider;
	use Silex\Provider\UrlGeneratorServiceProvider;
	use Silex\Provider\ValidatorServiceProvider;

	use Symfony\Component\HttpFoundation\Request;
	use Symfony\Component\Form\AbstractType;
	use Symfony\Component\Form\FormBuilderInterface;
	use Symfony\Component\OptionsResolver\OptionsResolverInterface;

	$app = new Application();

	$app['debug'] = true;

	$app->register(new FormServiceProvider());
	$app->register(new ServiceControllerServiceProvider());
	$app->register(new SessionServiceProvider());
	$app->register(new SwiftmailerServiceProvider());
	$app->register(new TranslationServiceProvider(), array(
	'locale_fallback' => 'en',
	));

	$app->register(new UrlGeneratorServiceProvider());
	$app->register(new ValidatorServiceProvider());

	// TWIG
	$app->register(new TwigServiceProvider(), array(
	'twig.path' => array(__DIR__.'/views'),
	));

	//
	// MODEL
	//

	class Task
	{
	protected $name;

	public function getName()
	{
	return $this->name;
	}

	public function setName($name)
	{
	$this->name = $name;
	return $this;
	}
	}

	class Project
	{
	protected $description;

	protected $tasks;

	public function __construct()
	{
	$this->tasks = array();
	}

	public function getDescription()
	{
	return $this->description;
	}

	public function setDescription($description)
	{
	$this->description = $description;
	return $this;
	}

	public function getTasks()
	{
	return $this->tasks;
	}
	public function addTask(Task $task)
	{
	if (!is_null($task) && !in_array($task, $this->tasks)) {
	$this->tasks[] = $task;
	}
	return $this;
	}
	public function removeTask(Task $task)
	{
	if (!is_null($task)) {
	$this->tasks = array_diff($this->tasks, array($task));
	}
	return $this;
	}
	}

	//
	// FORM
	//

	class TaskType extends AbstractType
	{
	public function buildForm(FormBuilderInterface $builder, array $options)
	{
	$builder->add('name', 'text', array(
	'required' => false
	));
	}

	public function setDefaultOptions(OptionsResolverInterface $resolver)
	{
	$resolver->setDefaults(array(
	'data_class' => '\Task',
	));
	}

	public function getName()
	{
	return 'task';
	}
	}

	class ProjectType extends AbstractType
	{
	public function buildForm(FormBuilderInterface $builder, array $options)
	{
	$builder->add('description', 'text', array())
	->add('tasks', 'collection', array(
	'type' => new TaskType(),
	'allow_add' => true,
	'by_reference' => false,
	'allow_delete' => true, // This causes the issue
	'required' => false
	))
	->add('submit', 'submit')
	;
	}

	public function setDefaultOptions(OptionsResolverInterface $resolver)
	{
	$resolver->setDefaults(array(
	'data_class' => '\Project',
	));
	}

	public function getName()
	{
	return 'project';
	}
	}

	//
	// Controller
	//

	$app->match('/', function (Request $request) use ($app) {
	$project = new Project();

	// dummy code - this is here just so that the Task has some tags
	// otherwise, this isn't an interesting example
	$task1 = new Task();
	$task1->setName('A Task');
	$project->addTask($task1);
	// end dummy code

	$form = $app['form.factory']->create(new ProjectType(), $project);

	$form->handleRequest($request);

	if ($form->isValid()) {
	$data = $form->getData();
	$debug = print_r($data, true);
	echo $debug;
	}

	return $app['twig']->render('test.html.twig', array(
	'form' => $form->createView(),
	));
	})
	->method('GET\|POST')
	;

	return $app;