Fix composite key serialization

[ddeboer]

Currently, calling unserialize() with some data previously returned from serialize() produces:

Array to string conversion

/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php:2913

This is caused by serialize() incorrectly serializing entities with primary keys (on doctrine/orm 2.4.):

"ref1":["Entity\\MyEntity",{"user":{"__initializer__":{},"__cloner__":{},"__isInitialized__":false},"somethingElse":{"__initializer__":null,"__cloner__":null,"__isInitialized__":true}}]

This seems to be caused by the identifier lookup for $simpleReferences not working properly. For each object constituting the composite key, it returns the object itself instead of its id. E.g.:

array(2) {
  [0] =>
  string(38) "Entity\MyEntity"
  [1] => 
    'user' =>
    class Proxies\__CG__\Entity\User#4711 (25) {
        // ...
    },
    'somethingElse' =>
    class Proxies\__CG__\Entity\SomethingElse#1234 (25) {
        // ...
    }

By adding a getReference() the identifier lookup works correctly. It now looks at $this->identities first, which holds the correct composite identities. Of course, the extra call does have a slight performance impact:

array(2) {
  [0] =>
  string(38) "Entity\MyEntity"
  [1] =>
  array(3) {
    'user' =>
    int(4)
    'somethingElse' =>
    int(1)
  }
}

[ddeboer]

This may be a (partial) fix for #135.

[lavoiesl]

Can you provide tests for that?

[lavoiesl]

@ddeboer, also, please rebase your commits.

[lavoiesl]

@ddeboer, I would like to be able to release this PR in 1.1 by tomorrow, do you think you would be able to care of it?

[ddeboer]

Rebased. Now working out how I can test this.

Btw, the original issue description is not wholly accurate any more after using the solution from #135.

[ddeboer]

Was unused.

[ddeboer]

Done.

[lavoiesl]

Awesome! Thank you.

[lavoiesl]

Sorry if I’m misunderstanding something, but wouldn’t this create ID collisions? Why not use implode('|', $proxyId)?

[ddeboer]

In most cases, where the related entity has a single (not composite) primary key, count($proxyId) === 1.

Imploding the keys is an option, but unfortunately won’t help much. When the references are unserialized, references are retrieved from the entity manager. However, Doctrine does not support something like:

$roleRef = $em->getReference(self::TEST_ENTITY_USER_ROLE, [
    'role' => 1,
    'user' => [    // Doctrine doesn’t like this nested composite key
        'id' => 1,
        'code' => '007'
    ]
]);

[lavoiesl]

After having carefully considered this PR and asked other guys on the Doctrine team, we won’t be accepting it as is. Before releasing support for composite keys, it will need to support all cases and/or have tests for all those.

I will reschedule this PR for 1.2 and will come back when I have a better understanding.

Thanks again.

[ddeboer]

I too prefer full support for nested composite keys, but as this requires changes in Doctrine itself I think starting simple, with support for unnested primary keys, is the way to go. Why does the solution have to tackle all cases at once? Why not work on a solution iteratively?