FriendsOfSymfony/FOSRestBundle — pull request #291 by borisguery (2012-09-04 13:53:08+00:00)
Title: Set $default to NULL to avoid array with empty value when an array parameter is not set in the Query

Use case:

Let's say we have an action with the following annotation:

```php
/**
* @QueryParam(name="filters", array=true)
*/
public function getFooAction($filters)
{
var_dump($filters);
}
````

Requesting `GET /foo` results in:

```php
array(1) {
[0]=>
string(0) ""
}
````

While it should should be:
```
array(0) { }
```

It is because by default, the `Param` as a `$default = ''` which actually represents an empty string. It should be `null` instead.