Doctrine 2 - Access level problems when using Class Table Inheritance

Question

I'm trying to implent the Class Table Inheritance Doctrine 2 offers in my Symfony 2 project. Let's say a have a Pizza class, Burito class and a MacAndCheese class which all inherit from a Food class.

The Food class has the following settings:

<?php

namespace Kitchen;

use Doctrine\ORM\Mapping as ORM;

/** 
 * @ORM\Entity
 * @ORM\Table(name="food")
 * @ORM\InheritanceType("JOINED")
 * @ORM\DiscriminatorColumn(name="dish", type="string")
 * @ORM\DiscriminatorMap({"pizza" = "Pizza", "burito" = "Burito", "mac" => "MacAndCheese"})
 */
class Food {

/**
 * @ORM\Id
 * @ORM\Column(type="integer")
 * @ORM\GeneratedValue(strategy="AUTO")
 */
protected $id;

And the inherited classes have these settings (Pizza for example):

<?php

namespace Kitchen;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="food_pizza")
 */
class Pizza extends Food {

When running doctrine:schema:update --force from the Symfony 2 app/console I get an error about the access level of $id in the children of Food (Pizza for example), stating it must be protected or weaker. I haven't declared $id anywhere in the Pizza, since I reckoned it would be inherited from Food.

So I tried to declare $id, but that gives me an error, cause I can't redeclare $id. I figure I need some kind of reference to $id from Food in Pizza, but the Doctrine 2 documentation didn't really give me a clear answer on what this would look like.

Hopefully you understand what I mean and can help me.

Answer 1

Apparently I should have investigated the code generated by doctrine:generate:entities a bit more. When I started my IDE this morning and seeing the code again, I noticed that it had 'copied' all of the inherited fields (like $id in Food, in the example above) to the children (Pizza, in the example above).

For some reason it decided to make these fields private. I manually changed the access level to protected in all of the classes and I tried to run doctrine:schema:update --force again: it worked!

So, as in many cases, the solution was a good night's rest! ;)

If someone comes up with a better solution and / or explanation for this problem, please do post it. I'd be more than happy to change the accepted answer.