UPGRADE FROM 3.1 to 3.2

FrameworkBundle

The doctrine/annotations dependency has been removed; require it via composer require doctrine/annotations if you are using annotations in your project
The symfony/security-core and symfony/security-csrf dependencies have been removed; require them via composer require symfony/security-core symfony/security-csrf if you depend on them and don't already depend on symfony/symfony
The symfony/templating dependency has been removed; require it via composer require symfony/templating if you depend on it and don't already depend on symfony/symfony
The symfony/translation dependency has been removed; require it via composer require symfony/translation if you depend on it and don't already depend on symfony/symfony
The symfony/asset dependency has been removed; require it via composer require symfony/asset if you depend on it and don't already depend on symfony/symfony
The Resources/public/images/* files have been removed.
The Resources/public/css/*.css files have been removed (they are now inlined in TwigBundle).
The Controller::getUser() method has been deprecated and will be removed in Symfony 4.0; typehint the security user object in the action instead.

Console

Setting unknown style options is deprecated and will throw an exception in Symfony 4.0.

DependencyInjection

Calling get() on a ContainerBuilder instance before compiling the container is deprecated and will throw an exception in Symfony 4.0.

Form

Calling isValid() on a Form instance before submitting it is deprecated and will throw an exception in Symfony 4.0.

Before:
```
if ($form->isValid()) {
    // ...
}
```
After:
```
if ($form->isSubmitted() && $form->isValid()) {
    // ...
}
```

FrameworkBundle

The service serializer.mapping.cache.doctrine.apc is deprecated. APCu should now be automatically used when available.

HttpKernel

DataCollector::varToString() is deprecated and will be removed in Symfony 4.0. Use the cloneVar() method instead.

HttpFoundation

Extending the following methods of Response is deprecated (these methods will be final in 4.0):
- setDate/getDate
- setExpires/getExpires
- setLastModified/getLastModified
- setProtocolVersion/getProtocolVersion
- setStatusCode/getStatusCode
- setCharset/getCharset
- setPrivate/setPublic
- getAge
- getMaxAge/setMaxAge
- setSharedMaxAge
- getTtl/setTtl
- setClientTtl
- getEtag/setEtag
- hasVary/getVary/setVary
- isInvalid/isSuccessful/isRedirection/isClientError/isServerError
- isOk/isForbidden/isNotFound/isRedirect/isEmpty

Validator

Tests\Constraints\AbstractConstraintValidatorTest has been deprecated in favor of Test\ConstraintValidatorTestCase.

Before:

// ...
use Symfony\Component\Validator\Tests\Constraints\AbstractConstraintValidatorTest;

class MyCustomValidatorTest extends AbstractConstraintValidatorTest
{
    // ...
}

After:

// ...
use Symfony\Component\Validator\Test\ConstraintValidatorTestCase;

class MyCustomValidatorTest extends ConstraintValidatorTestCase
{
    // ...
}

Setting the strict option of the Choice Constraint to false has been deprecated and the option will be changed to true as of 4.0.

// ...
use Symfony\Component\Validator\Constraints as Assert;

class MyEntity
{
    /**
     * @Assert\Choice(choices={"MR", "MRS"}, strict=true)
     */
    private $salutation;
}

Yaml

Support for silently ignoring duplicate mapping keys in YAML has been deprecated and will lead to a ParseException in Symfony 4.0.
Mappings with a colon (:) that is not followed by a whitespace are deprecated and will lead to a ParseException in Symfony 4.0 (e.g. foo:bar must be foo: bar).

Uh oh!