Doctrine 2 self-referencing entity won't return the parent id - doctrine-orm

Question

I've set up a self-referencing entity per the manual here:
http://www.google.com/url?sa=D&q=http://www.doctrine-project.org/docs/orm/2.0/en/reference/association-mapping.html%23one-to-many-self-referencing
My class is Page (instead of Category, like in the docs). In my entity
class I have a toArray() method that I've implemented that will give
me back the values of my member variables. For those fields that are
associations, I've made sure to grab the associated class object then
grab the id. I'm doing this to populate a form. Here is the code from
my toArray() method in my Page entity as well as my PageService
function to grab a Page object and my Page Controller code that calls
toArray() to populate my form.
http://pastie.org/1686419
As I say in the code comments, when the toArray() method is called in
the Page Controller, all values get populated except for parent id.
page_type is also a ManyToOne association and it gets populated no
problem. Explicitly grabbing the parent id from the Page object
outside of the toArray() method (in the Page Controller) does return
the parent id value. (See code.)
As a side note, I'm using __get() and __set() in my Page entity instead of full blown getters/setters.

Answer 1

I think it is because you are getting caught out by proxies. When you have an association in Doctrine 2, the related objects are not returned directly as objects, but as subclasses which do not fill their properties until a method is called (because of lazy loading to save database queries).
Since you are calling the property directly (with $this->parent->id) without invoking any method the object properties are all empty.
This page http://www.doctrine-project.org/docs/orm/2.0/en/tutorials/getting-started-xml-edition.html#a-first-prototype has a warning about this type of thing in the warning box. Although yours isn't a public property, you are accessing as though it were because that object is of the same class and the same problem is occuring.

Answer 2

Not sure of exactly what is causing your described behavior, but you're probably better anyway to have your toArray() method call getters/setters rather than having toArray() operate directly on the class properties. This will give you consistency so that if you implement custom getters for certain properties, you'll always get back the same result from toArray() and the getter.
A rough example:
<?php
/** #Entity */
class MyEntity {
// ....
/** #Column */
protected $foo;
public function setFoo($val)
{
$this->foo = $val;
}
public function getFoo()
{
return 'hello ' . $this->foo;
}
public function toArray()
{
$fields = array('foo');
$values = array();
foreach($fields as $field) {
$method = 'get' . ucfirst($field);
if (is_callable(array($this, $method)) {
$fields[$field] = $this->$method();
} else {
$fields[$field] = $this->$field;
}
}
return $fields;
}
}
Now you get the same result:
<?php
$e = new MyEntity;
$e->setFoo('world');
$e->getFoo(); // returns 'hello world'
$e->toArray(); // returns array('foo' => 'hello world')