UPGRADE FROM 2.1 to 2.2

HttpFoundation

The MongoDbSessionHandler default field names and timestamp type have changed.

The sess_ prefix was removed from default field names. The session ID is now stored in the _id field by default. The session date is now stored as a MongoDate instead of MongoTimestamp, which also makes it possible to use TTL collections in MongoDB 2.2+ instead of relying on the gc() method.
The Stopwatch functionality was moved from HttpKernel\Debug to its own component
The _method request parameter support has been disabled by default (call Request::enableHttpMethodParameterOverride() to enable it).

Deprecations

The Request::splitHttpAcceptHeader() is deprecated and will be removed in 2.3.

You should now use the AcceptHeader class which give you fluent methods to parse request accept-* headers. Some examples:

$accept = AcceptHeader::fromString($request->headers->get('Accept'));
if ($accept->has('text/html') {
    $item = $accept->get('html');
    $charset = $item->getAttribute('charset', 'utf-8');
    $quality = $item->getQuality();
}

// accepts items are sorted by descending quality
$accepts = AcceptHeader::fromString($request->headers->get('Accept'))->all();

Form

The PasswordType is now not trimmed by default.

Routing

RouteCollection does not behave like a tree structure anymore but as a flat array of Routes. So when using PHP to build the RouteCollection, you must make sure to add routes to the sub-collection before adding it to the parent collection (this is not relevant when using YAML or XML for Route definitions).

Before:

$rootCollection = new RouteCollection();
$subCollection = new RouteCollection();
$rootCollection->addCollection($subCollection);
$subCollection->add('foo', new Route('/foo'));

After:

$rootCollection = new RouteCollection();
$subCollection = new RouteCollection();
$subCollection->add('foo', new Route('/foo'));
$rootCollection->addCollection($subCollection);

Also one must call addCollection from the bottom to the top hierarchy. So the correct sequence is the following (and not the reverse):

$childCollection->->addCollection($grandchildCollection);
$rootCollection->addCollection($childCollection);

The methods RouteCollection::getParent() and RouteCollection::getRoot() have been deprecated and will be removed in Symfony 2.3.

Validator

Interfaces were created for the classes ConstraintViolation, ConstraintViolationList, GlobalExecutionContext and ExecutionContext. If you type hinted against any of these classes, you are recommended to type hint against their interfaces now.

Before:

use Symfony\Component\Validator\ExecutionContext;

public function validateCustomLogic(ExecutionContext $context)

After:

use Symfony\Component\Validator\ExecutionContextInterface;

public function validateCustomLogic(ExecutionContextInterface $context)

For all implementations of ConstraintValidatorInterface, this change is mandatory for the initialize method:

Before:

use Symfony\Component\Validator\ConstraintValidatorInterface;
use Symfony\Component\Validator\ExecutionContext;

class MyValidator implements ConstraintValidatorInterface
{
    public function initialize(ExecutionContext $context)
    {
        // ...
    }
}

After:

use Symfony\Component\Validator\ConstraintValidatorInterface;
use Symfony\Component\Validator\ExecutionContextInterface;

class MyValidator implements ConstraintValidatorInterface
{
    public function initialize(ExecutionContextInterface $context)
    {
        // ...
    }
}

Deprecations

The interface ClassMetadataFactoryInterface was deprecated and will be removed in Symfony 2.3. You should implement MetadataFactoryInterface instead, which changes the name of the method getClassMetadata to getMetadataFor and accepts arbitrary values (e.g. class names, objects, numbers etc.). In your implementation, you should throw a NoSuchMetadataException if you don't support metadata for the given value.

Before:

use Symfony\Component\Validator\Mapping\ClassMetadataFactoryInterface;

class MyMetadataFactory implements ClassMetadataFactoryInterface
{
    public function getClassMetadata($class)
    {
        // ...
    }
}

After:

use Symfony\Component\Validator\MetadataFactoryInterface;
use Symfony\Component\Validator\Exception\NoSuchMetadataException;

class MyMetadataFactory implements MetadataFactoryInterface
{
    public function getMetadataFor($value)
    {
        if (is_object($value)) {
            $value = get_class($value);
        }

        if (!is_string($value) || (!class_exists($value) && !interface_exists($value))) {
            throw new NoSuchMetadataException(...);
        }

        // ...
    }
}

The return value of ValidatorInterface::getMetadataFactory() was also changed to return MetadataFactoryInterface. Make sure to replace calls to getClassMetadata by getMetadataFor on the return value of this method.

Before:

$metadataFactory = $validator->getMetadataFactory();
$metadata = $metadataFactory->getClassMetadata('Vendor\MyClass');

After:

$metadataFactory = $validator->getMetadataFactory();
$metadata = $metadataFactory->getMetadataFor('Vendor\MyClass');

The class GraphWalker and the accessor ExecutionContext::getGraphWalker() were deprecated and will be removed in Symfony 2.3. You should use the methods ExecutionContextInterface::validate() and ExecutionContextInterface::validateValue() instead.

Before:

use Symfony\Component\Validator\ExecutionContext;

public function validateCustomLogic(ExecutionContext $context)
{
    if (/* ... */) {
        $path = $context->getPropertyPath();
        $group = $context->getGroup();

        if (!empty($path)) {
            $path .= '.';
        }

        $context->getGraphWalker()->walkReference($someObject, $group, $path . 'myProperty', false);
    }
}

After:

use Symfony\Component\Validator\ExecutionContextInterface;

public function validateCustomLogic(ExecutionContextInterface $context)
{
    if (/* ... */) {
        $context->validate($someObject, 'myProperty');
    }
}

The method ExecutionContext::addViolationAtSubPath() was deprecated and will be removed in Symfony 2.3. You should use addViolationAt() instead.

Before:

use Symfony\Component\Validator\ExecutionContext;

public function validateCustomLogic(ExecutionContext $context)
{
    if (/* ... */) {
        $context->addViolationAtSubPath('myProperty', 'This value is invalid');
    }
}

After:

use Symfony\Component\Validator\ExecutionContextInterface;

public function validateCustomLogic(ExecutionContextInterface $context)
{
    if (/* ... */) {
        $context->addViolationAt('myProperty', 'This value is invalid');
    }
}

The methods ExecutionContext::getCurrentClass(), ExecutionContext::getCurrentProperty() and ExecutionContext::getCurrentValue() were deprecated and will be removed in Symfony 2.3. Use the methods getClassName(), getPropertyName() and getValue() instead.

Before:

use Symfony\Component\Validator\ExecutionContext;

public function validateCustomLogic(ExecutionContext $context)
{
    $class = $context->getCurrentClass();
    $property = $context->getCurrentProperty();
    $value = $context->getCurrentValue();

    // ...
}

After:

use Symfony\Component\Validator\ExecutionContextInterface;

public function validateCustomLogic(ExecutionContextInterface $context)
{
    $class = $context->getClassName();
    $property = $context->getPropertyName();
    $value = $context->getValue();

    // ...
}